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-rw-r--r--Documentation/ABI/testing/sysfs-devices-power79
-rw-r--r--Documentation/ABI/testing/sysfs-power13
-rw-r--r--Documentation/DocBook/v4l/io.xml3
-rw-r--r--Documentation/DocBook/v4l/vidioc-qbuf.xml40
-rw-r--r--Documentation/DocBook/v4l/vidioc-querybuf.xml7
-rw-r--r--Documentation/DocBook/v4l/vidioc-reqbufs.xml36
-rw-r--r--Documentation/RCU/00-INDEX10
-rw-r--r--Documentation/RCU/RTFP.txt61
-rw-r--r--Documentation/RCU/checklist.txt208
-rw-r--r--Documentation/RCU/lockdep.txt67
-rw-r--r--Documentation/RCU/rcu.txt48
-rw-r--r--Documentation/RCU/stallwarn.txt58
-rw-r--r--Documentation/RCU/torture.txt12
-rw-r--r--Documentation/RCU/whatisRCU.txt16
-rw-r--r--Documentation/cachetlb.txt24
-rw-r--r--Documentation/dontdiff1
-rw-r--r--Documentation/dvb/get_dvb_firmware23
-rw-r--r--Documentation/feature-removal-schedule.txt26
-rw-r--r--Documentation/filesystems/dentry-locking.txt3
-rw-r--r--Documentation/kernel-parameters.txt26
-rw-r--r--Documentation/lguest/lguest.c1
-rw-r--r--Documentation/pcmcia/locking.txt118
-rw-r--r--Documentation/powerpc/dts-bindings/fsl/mpc5121-psc.txt70
-rw-r--r--Documentation/powerpc/dts-bindings/fsl/spi.txt7
-rw-r--r--Documentation/powerpc/ptrace.txt134
-rw-r--r--Documentation/s390/CommonIO6
-rw-r--r--Documentation/s390/driver-model.txt4
-rw-r--r--Documentation/scsi/ChangeLog.megaraid_sas16
-rw-r--r--Documentation/trace/ftrace-design.txt5
-rw-r--r--Documentation/trace/kprobetrace.txt57
-rw-r--r--Documentation/video4linux/CARDLIST.cx238851
-rw-r--r--Documentation/video4linux/CARDLIST.saa71341
-rw-r--r--Documentation/video4linux/CARDLIST.tuner1
-rw-r--r--Documentation/video4linux/README.tlg230047
-rw-r--r--Documentation/video4linux/gspca.txt25
-rw-r--r--Documentation/video4linux/v4l2-framework.txt106
-rw-r--r--Documentation/video4linux/videobuf360
-rw-r--r--Documentation/x86/x86_64/boot-options.txt20
38 files changed, 1389 insertions, 351 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power
new file mode 100644
index 000000000000..6123c523bfd7
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-power
@@ -0,0 +1,79 @@
1What: /sys/devices/.../power/
2Date: January 2009
3Contact: Rafael J. Wysocki <rjw@sisk.pl>
4Description:
5 The /sys/devices/.../power directory contains attributes
6 allowing the user space to check and modify some power
7 management related properties of given device.
8
9What: /sys/devices/.../power/wakeup
10Date: January 2009
11Contact: Rafael J. Wysocki <rjw@sisk.pl>
12Description:
13 The /sys/devices/.../power/wakeup attribute allows the user
14 space to check if the device is enabled to wake up the system
15 from sleep states, such as the memory sleep state (suspend to
16 RAM) and hibernation (suspend to disk), and to enable or disable
17 it to do that as desired.
18
19 Some devices support "wakeup" events, which are hardware signals
20 used to activate the system from a sleep state. Such devices
21 have one of the following two values for the sysfs power/wakeup
22 file:
23
24 + "enabled\n" to issue the events;
25 + "disabled\n" not to do so;
26
27 In that cases the user space can change the setting represented
28 by the contents of this file by writing either "enabled", or
29 "disabled" to it.
30
31 For the devices that are not capable of generating system wakeup
32 events this file contains "\n". In that cases the user space
33 cannot modify the contents of this file and the device cannot be
34 enabled to wake up the system.
35
36What: /sys/devices/.../power/control
37Date: January 2009
38Contact: Rafael J. Wysocki <rjw@sisk.pl>
39Description:
40 The /sys/devices/.../power/control attribute allows the user
41 space to control the run-time power management of the device.
42
43 All devices have one of the following two values for the
44 power/control file:
45
46 + "auto\n" to allow the device to be power managed at run time;
47 + "on\n" to prevent the device from being power managed;
48
49 The default for all devices is "auto", which means that they may
50 be subject to automatic power management, depending on their
51 drivers. Changing this attribute to "on" prevents the driver
52 from power managing the device at run time. Doing that while
53 the device is suspended causes it to be woken up.
54
55What: /sys/devices/.../power/async
56Date: January 2009
57Contact: Rafael J. Wysocki <rjw@sisk.pl>
58Description:
59 The /sys/devices/.../async attribute allows the user space to
60 enable or diasble the device's suspend and resume callbacks to
61 be executed asynchronously (ie. in separate threads, in parallel
62 with the main suspend/resume thread) during system-wide power
63 transitions (eg. suspend to RAM, hibernation).
64
65 All devices have one of the following two values for the
66 power/async file:
67
68 + "enabled\n" to permit the asynchronous suspend/resume;
69 + "disabled\n" to forbid it;
70
71 The value of this attribute may be changed by writing either
72 "enabled", or "disabled" to it.
73
74 It generally is unsafe to permit the asynchronous suspend/resume
75 of a device unless it is certain that all of the PM dependencies
76 of the device are known to the PM core. However, for some
77 devices this attribute is set to "enabled" by bus type code or
78 device drivers and in that cases it should be safe to leave the
79 default value.
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index dcff4d0623ad..d6a801f45b48 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -101,3 +101,16 @@ Description:
101 101
102 CAUTION: Using it will cause your machine's real-time (CMOS) 102 CAUTION: Using it will cause your machine's real-time (CMOS)
103 clock to be set to a random invalid time after a resume. 103 clock to be set to a random invalid time after a resume.
104
105What: /sys/power/pm_async
106Date: January 2009
107Contact: Rafael J. Wysocki <rjw@sisk.pl>
108Description:
109 The /sys/power/pm_async file controls the switch allowing the
110 user space to enable or disable asynchronous suspend and resume
111 of devices. If enabled, this feature will cause some device
112 drivers' suspend and resume callbacks to be executed in parallel
113 with each other and with the main suspend thread. It is enabled
114 if this file contains "1", which is the default. It may be
115 disabled by writing "0" to this file, in which case all devices
116 will be suspended and resumed synchronously.
diff --git a/Documentation/DocBook/v4l/io.xml b/Documentation/DocBook/v4l/io.xml
index f92f24323b2a..e870330cbf77 100644
--- a/Documentation/DocBook/v4l/io.xml
+++ b/Documentation/DocBook/v4l/io.xml
@@ -589,7 +589,8 @@ number of a video input as in &v4l2-input; field
589 <entry></entry> 589 <entry></entry>
590 <entry>A place holder for future extensions and custom 590 <entry>A place holder for future extensions and custom
591(driver defined) buffer types 591(driver defined) buffer types
592<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher.</entry> 592<constant>V4L2_BUF_TYPE_PRIVATE</constant> and higher. Applications
593should set this to 0.</entry>
593 </row> 594 </row>
594 </tbody> 595 </tbody>
595 </tgroup> 596 </tgroup>
diff --git a/Documentation/DocBook/v4l/vidioc-qbuf.xml b/Documentation/DocBook/v4l/vidioc-qbuf.xml
index 187081778154..b843bd7b3897 100644
--- a/Documentation/DocBook/v4l/vidioc-qbuf.xml
+++ b/Documentation/DocBook/v4l/vidioc-qbuf.xml
@@ -54,12 +54,10 @@ to enqueue an empty (capturing) or filled (output) buffer in the
54driver's incoming queue. The semantics depend on the selected I/O 54driver's incoming queue. The semantics depend on the selected I/O
55method.</para> 55method.</para>
56 56
57 <para>To enqueue a <link linkend="mmap">memory mapped</link> 57 <para>To enqueue a buffer applications set the <structfield>type</structfield>
58buffer applications set the <structfield>type</structfield> field of a 58field of a &v4l2-buffer; to the same buffer type as was previously used
59&v4l2-buffer; to the same buffer type as previously &v4l2-format; 59with &v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers;
60<structfield>type</structfield> and &v4l2-requestbuffers; 60<structfield>type</structfield>. Applications must also set the
61<structfield>type</structfield>, the <structfield>memory</structfield>
62field to <constant>V4L2_MEMORY_MMAP</constant> and the
63<structfield>index</structfield> field. Valid index numbers range from 61<structfield>index</structfield> field. Valid index numbers range from
64zero to the number of buffers allocated with &VIDIOC-REQBUFS; 62zero to the number of buffers allocated with &VIDIOC-REQBUFS;
65(&v4l2-requestbuffers; <structfield>count</structfield>) minus one. The 63(&v4l2-requestbuffers; <structfield>count</structfield>) minus one. The
@@ -70,8 +68,19 @@ intended for output (<structfield>type</structfield> is
70<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also 68<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also
71initialize the <structfield>bytesused</structfield>, 69initialize the <structfield>bytesused</structfield>,
72<structfield>field</structfield> and 70<structfield>field</structfield> and
73<structfield>timestamp</structfield> fields. See <xref 71<structfield>timestamp</structfield> fields, see <xref
74 linkend="buffer" /> for details. When 72linkend="buffer" /> for details.
73Applications must also set <structfield>flags</structfield> to 0. If a driver
74supports capturing from specific video inputs and you want to specify a video
75input, then <structfield>flags</structfield> should be set to
76<constant>V4L2_BUF_FLAG_INPUT</constant> and the field
77<structfield>input</structfield> must be initialized to the desired input.
78The <structfield>reserved</structfield> field must be set to 0.
79</para>
80
81 <para>To enqueue a <link linkend="mmap">memory mapped</link>
82buffer applications set the <structfield>memory</structfield>
83field to <constant>V4L2_MEMORY_MMAP</constant>. When
75<constant>VIDIOC_QBUF</constant> is called with a pointer to this 84<constant>VIDIOC_QBUF</constant> is called with a pointer to this
76structure the driver sets the 85structure the driver sets the
77<constant>V4L2_BUF_FLAG_MAPPED</constant> and 86<constant>V4L2_BUF_FLAG_MAPPED</constant> and
@@ -81,14 +90,10 @@ structure the driver sets the
81&EINVAL;.</para> 90&EINVAL;.</para>
82 91
83 <para>To enqueue a <link linkend="userp">user pointer</link> 92 <para>To enqueue a <link linkend="userp">user pointer</link>
84buffer applications set the <structfield>type</structfield> field of a 93buffer applications set the <structfield>memory</structfield>
85&v4l2-buffer; to the same buffer type as previously &v4l2-format; 94field to <constant>V4L2_MEMORY_USERPTR</constant>, the
86<structfield>type</structfield> and &v4l2-requestbuffers;
87<structfield>type</structfield>, the <structfield>memory</structfield>
88field to <constant>V4L2_MEMORY_USERPTR</constant> and the
89<structfield>m.userptr</structfield> field to the address of the 95<structfield>m.userptr</structfield> field to the address of the
90buffer and <structfield>length</structfield> to its size. When the 96buffer and <structfield>length</structfield> to its size.
91buffer is intended for output additional fields must be set as above.
92When <constant>VIDIOC_QBUF</constant> is called with a pointer to this 97When <constant>VIDIOC_QBUF</constant> is called with a pointer to this
93structure the driver sets the <constant>V4L2_BUF_FLAG_QUEUED</constant> 98structure the driver sets the <constant>V4L2_BUF_FLAG_QUEUED</constant>
94flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and 99flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and
@@ -96,13 +101,14 @@ flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and
96<structfield>flags</structfield> field, or it returns an error code. 101<structfield>flags</structfield> field, or it returns an error code.
97This ioctl locks the memory pages of the buffer in physical memory, 102This ioctl locks the memory pages of the buffer in physical memory,
98they cannot be swapped out to disk. Buffers remain locked until 103they cannot be swapped out to disk. Buffers remain locked until
99dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl are 104dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is
100called, or until the device is closed.</para> 105called, or until the device is closed.</para>
101 106
102 <para>Applications call the <constant>VIDIOC_DQBUF</constant> 107 <para>Applications call the <constant>VIDIOC_DQBUF</constant>
103ioctl to dequeue a filled (capturing) or displayed (output) buffer 108ioctl to dequeue a filled (capturing) or displayed (output) buffer
104from the driver's outgoing queue. They just set the 109from the driver's outgoing queue. They just set the
105<structfield>type</structfield> and <structfield>memory</structfield> 110<structfield>type</structfield>, <structfield>memory</structfield>
111and <structfield>reserved</structfield>
106fields of a &v4l2-buffer; as above, when <constant>VIDIOC_DQBUF</constant> 112fields of a &v4l2-buffer; as above, when <constant>VIDIOC_DQBUF</constant>
107is called with a pointer to this structure the driver fills the 113is called with a pointer to this structure the driver fills the
108remaining fields or returns an error code.</para> 114remaining fields or returns an error code.</para>
diff --git a/Documentation/DocBook/v4l/vidioc-querybuf.xml b/Documentation/DocBook/v4l/vidioc-querybuf.xml
index d834993e6191..e649805a4908 100644
--- a/Documentation/DocBook/v4l/vidioc-querybuf.xml
+++ b/Documentation/DocBook/v4l/vidioc-querybuf.xml
@@ -54,12 +54,13 @@ buffer at any time after buffers have been allocated with the
54&VIDIOC-REQBUFS; ioctl.</para> 54&VIDIOC-REQBUFS; ioctl.</para>
55 55
56 <para>Applications set the <structfield>type</structfield> field 56 <para>Applications set the <structfield>type</structfield> field
57 of a &v4l2-buffer; to the same buffer type as previously 57 of a &v4l2-buffer; to the same buffer type as was previously used with
58&v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers; 58&v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers;
59<structfield>type</structfield>, and the <structfield>index</structfield> 59<structfield>type</structfield>, and the <structfield>index</structfield>
60 field. Valid index numbers range from zero 60 field. Valid index numbers range from zero
61to the number of buffers allocated with &VIDIOC-REQBUFS; 61to the number of buffers allocated with &VIDIOC-REQBUFS;
62 (&v4l2-requestbuffers; <structfield>count</structfield>) minus one. 62 (&v4l2-requestbuffers; <structfield>count</structfield>) minus one.
63The <structfield>reserved</structfield> field should to set to 0.
63After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to 64After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to
64 this structure drivers return an error code or fill the rest of 65 this structure drivers return an error code or fill the rest of
65the structure.</para> 66the structure.</para>
@@ -68,8 +69,8 @@ the structure.</para>
68<constant>V4L2_BUF_FLAG_MAPPED</constant>, 69<constant>V4L2_BUF_FLAG_MAPPED</constant>,
69<constant>V4L2_BUF_FLAG_QUEUED</constant> and 70<constant>V4L2_BUF_FLAG_QUEUED</constant> and
70<constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The 71<constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The
71<structfield>memory</structfield> field will be set to 72<structfield>memory</structfield> field will be set to the current
72<constant>V4L2_MEMORY_MMAP</constant>, the <structfield>m.offset</structfield> 73I/O method, the <structfield>m.offset</structfield>
73contains the offset of the buffer from the start of the device memory, 74contains the offset of the buffer from the start of the device memory,
74the <structfield>length</structfield> field its size. The driver may 75the <structfield>length</structfield> field its size. The driver may
75or may not set the remaining fields and flags, they are meaningless in 76or may not set the remaining fields and flags, they are meaningless in
diff --git a/Documentation/DocBook/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/v4l/vidioc-reqbufs.xml
index bab38084454f..1c0816372074 100644
--- a/Documentation/DocBook/v4l/vidioc-reqbufs.xml
+++ b/Documentation/DocBook/v4l/vidioc-reqbufs.xml
@@ -54,23 +54,23 @@ I/O. Memory mapped buffers are located in device memory and must be
54allocated with this ioctl before they can be mapped into the 54allocated with this ioctl before they can be mapped into the
55application's address space. User buffers are allocated by 55application's address space. User buffers are allocated by
56applications themselves, and this ioctl is merely used to switch the 56applications themselves, and this ioctl is merely used to switch the
57driver into user pointer I/O mode.</para> 57driver into user pointer I/O mode and to setup some internal structures.</para>
58 58
59 <para>To allocate device buffers applications initialize three 59 <para>To allocate device buffers applications initialize all
60fields of a <structname>v4l2_requestbuffers</structname> structure. 60fields of the <structname>v4l2_requestbuffers</structname> structure.
61They set the <structfield>type</structfield> field to the respective 61They set the <structfield>type</structfield> field to the respective
62stream or buffer type, the <structfield>count</structfield> field to 62stream or buffer type, the <structfield>count</structfield> field to
63the desired number of buffers, and <structfield>memory</structfield> 63the desired number of buffers, <structfield>memory</structfield>
64must be set to <constant>V4L2_MEMORY_MMAP</constant>. When the ioctl 64must be set to the requested I/O method and the reserved array
65is called with a pointer to this structure the driver attempts to 65must be zeroed. When the ioctl
66allocate the requested number of buffers and stores the actual number 66is called with a pointer to this structure the driver will attempt to allocate
67the requested number of buffers and it stores the actual number
67allocated in the <structfield>count</structfield> field. It can be 68allocated in the <structfield>count</structfield> field. It can be
68smaller than the number requested, even zero, when the driver runs out 69smaller than the number requested, even zero, when the driver runs out
69of free memory. A larger number is possible when the driver requires 70of free memory. A larger number is also possible when the driver requires
70more buffers to function correctly.<footnote> 71more buffers to function correctly. For example video output requires at least two buffers,
71 <para>For example video output requires at least two buffers,
72one displayed and one filled by the application.</para> 72one displayed and one filled by the application.</para>
73 </footnote> When memory mapping I/O is not supported the ioctl 73 <para>When the I/O method is not supported the ioctl
74returns an &EINVAL;.</para> 74returns an &EINVAL;.</para>
75 75
76 <para>Applications can call <constant>VIDIOC_REQBUFS</constant> 76 <para>Applications can call <constant>VIDIOC_REQBUFS</constant>
@@ -81,14 +81,6 @@ in progress, an implicit &VIDIOC-STREAMOFF;. <!-- mhs: I see no
81reason why munmap()ping one or even all buffers must imply 81reason why munmap()ping one or even all buffers must imply
82streamoff.--></para> 82streamoff.--></para>
83 83
84 <para>To negotiate user pointer I/O, applications initialize only
85the <structfield>type</structfield> field and set
86<structfield>memory</structfield> to
87<constant>V4L2_MEMORY_USERPTR</constant>. When the ioctl is called
88with a pointer to this structure the driver prepares for user pointer
89I/O, when this I/O method is not supported the ioctl returns an
90&EINVAL;.</para>
91
92 <table pgwide="1" frame="none" id="v4l2-requestbuffers"> 84 <table pgwide="1" frame="none" id="v4l2-requestbuffers">
93 <title>struct <structname>v4l2_requestbuffers</structname></title> 85 <title>struct <structname>v4l2_requestbuffers</structname></title>
94 <tgroup cols="3"> 86 <tgroup cols="3">
@@ -97,9 +89,7 @@ I/O, when this I/O method is not supported the ioctl returns an
97 <row> 89 <row>
98 <entry>__u32</entry> 90 <entry>__u32</entry>
99 <entry><structfield>count</structfield></entry> 91 <entry><structfield>count</structfield></entry>
100 <entry>The number of buffers requested or granted. This 92 <entry>The number of buffers requested or granted.</entry>
101field is only used when <structfield>memory</structfield> is set to
102<constant>V4L2_MEMORY_MMAP</constant>.</entry>
103 </row> 93 </row>
104 <row> 94 <row>
105 <entry>&v4l2-buf-type;</entry> 95 <entry>&v4l2-buf-type;</entry>
@@ -120,7 +110,7 @@ as the &v4l2-format; <structfield>type</structfield> field. See <xref
120 <entry><structfield>reserved</structfield>[2]</entry> 110 <entry><structfield>reserved</structfield>[2]</entry>
121 <entry>A place holder for future extensions and custom 111 <entry>A place holder for future extensions and custom
122(driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and 112(driver defined) buffer types <constant>V4L2_BUF_TYPE_PRIVATE</constant> and
123higher.</entry> 113higher. This array should be zeroed by applications.</entry>
124 </row> 114 </row>
125 </tbody> 115 </tbody>
126 </tgroup> 116 </tgroup>
diff --git a/Documentation/RCU/00-INDEX b/Documentation/RCU/00-INDEX
index 9bb62f7b89c3..71b6f500ddb9 100644
--- a/Documentation/RCU/00-INDEX
+++ b/Documentation/RCU/00-INDEX
@@ -6,16 +6,22 @@ checklist.txt
6 - Review Checklist for RCU Patches 6 - Review Checklist for RCU Patches
7listRCU.txt 7listRCU.txt
8 - Using RCU to Protect Read-Mostly Linked Lists 8 - Using RCU to Protect Read-Mostly Linked Lists
9lockdep.txt
10 - RCU and lockdep checking
9NMI-RCU.txt 11NMI-RCU.txt
10 - Using RCU to Protect Dynamic NMI Handlers 12 - Using RCU to Protect Dynamic NMI Handlers
13rcubarrier.txt
14 - RCU and Unloadable Modules
15rculist_nulls.txt
16 - RCU list primitives for use with SLAB_DESTROY_BY_RCU
11rcuref.txt 17rcuref.txt
12 - Reference-count design for elements of lists/arrays protected by RCU 18 - Reference-count design for elements of lists/arrays protected by RCU
13rcu.txt 19rcu.txt
14 - RCU Concepts 20 - RCU Concepts
15rcubarrier.txt
16 - Unloading modules that use RCU callbacks
17RTFP.txt 21RTFP.txt
18 - List of RCU papers (bibliography) going back to 1980. 22 - List of RCU papers (bibliography) going back to 1980.
23stallwarn.txt
24 - RCU CPU stall warnings (CONFIG_RCU_CPU_STALL_DETECTOR)
19torture.txt 25torture.txt
20 - RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST) 26 - RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
21trace.txt 27trace.txt
diff --git a/Documentation/RCU/RTFP.txt b/Documentation/RCU/RTFP.txt
index d2b85237c76e..5aea459e3dd6 100644
--- a/Documentation/RCU/RTFP.txt
+++ b/Documentation/RCU/RTFP.txt
@@ -25,10 +25,10 @@ to be referencing the data structure. However, this mechanism was not
25optimized for modern computer systems, which is not surprising given 25optimized for modern computer systems, which is not surprising given
26that these overheads were not so expensive in the mid-80s. Nonetheless, 26that these overheads were not so expensive in the mid-80s. Nonetheless,
27passive serialization appears to be the first deferred-destruction 27passive serialization appears to be the first deferred-destruction
28mechanism to be used in production. Furthermore, the relevant patent has 28mechanism to be used in production. Furthermore, the relevant patent
29lapsed, so this approach may be used in non-GPL software, if desired. 29has lapsed, so this approach may be used in non-GPL software, if desired.
30(In contrast, use of RCU is permitted only in software licensed under 30(In contrast, implementation of RCU is permitted only in software licensed
31GPL. Sorry!!!) 31under either GPL or LGPL. Sorry!!!)
32 32
33In 1990, Pugh [Pugh90] noted that explicitly tracking which threads 33In 1990, Pugh [Pugh90] noted that explicitly tracking which threads
34were reading a given data structure permitted deferred free to operate 34were reading a given data structure permitted deferred free to operate
@@ -150,6 +150,18 @@ preemptible RCU [PaulEMcKenney2007PreemptibleRCU], and the three-part
150LWN "What is RCU?" series [PaulEMcKenney2007WhatIsRCUFundamentally, 150LWN "What is RCU?" series [PaulEMcKenney2007WhatIsRCUFundamentally,
151PaulEMcKenney2008WhatIsRCUUsage, and PaulEMcKenney2008WhatIsRCUAPI]. 151PaulEMcKenney2008WhatIsRCUUsage, and PaulEMcKenney2008WhatIsRCUAPI].
152 152
1532008 saw a journal paper on real-time RCU [DinakarGuniguntala2008IBMSysJ],
154a history of how Linux changed RCU more than RCU changed Linux
155[PaulEMcKenney2008RCUOSR], and a design overview of hierarchical RCU
156[PaulEMcKenney2008HierarchicalRCU].
157
1582009 introduced user-level RCU algorithms [PaulEMcKenney2009MaliciousURCU],
159which Mathieu Desnoyers is now maintaining [MathieuDesnoyers2009URCU]
160[MathieuDesnoyersPhD]. TINY_RCU [PaulEMcKenney2009BloatWatchRCU] made
161its appearance, as did expedited RCU [PaulEMcKenney2009expeditedRCU].
162The problem of resizeable RCU-protected hash tables may now be on a path
163to a solution [JoshTriplett2009RPHash].
164
153Bibtex Entries 165Bibtex Entries
154 166
155@article{Kung80 167@article{Kung80
@@ -730,6 +742,11 @@ Revised:
730" 742"
731} 743}
732 744
745#
746# "What is RCU?" LWN series.
747#
748########################################################################
749
733@article{DinakarGuniguntala2008IBMSysJ 750@article{DinakarGuniguntala2008IBMSysJ
734,author="D. Guniguntala and P. E. McKenney and J. Triplett and J. Walpole" 751,author="D. Guniguntala and P. E. McKenney and J. Triplett and J. Walpole"
735,title="The read-copy-update mechanism for supporting real-time applications on shared-memory multiprocessor systems with {Linux}" 752,title="The read-copy-update mechanism for supporting real-time applications on shared-memory multiprocessor systems with {Linux}"
@@ -820,3 +837,39 @@ Revised:
820 Uniprocessor assumptions allow simplified RCU implementation. 837 Uniprocessor assumptions allow simplified RCU implementation.
821" 838"
822} 839}
840
841@unpublished{PaulEMcKenney2009expeditedRCU
842,Author="Paul E. McKenney"
843,Title="[{PATCH} -tip 0/3] expedited 'big hammer' {RCU} grace periods"
844,month="June"
845,day="25"
846,year="2009"
847,note="Available:
848\url{http://lkml.org/lkml/2009/6/25/306}
849[Viewed August 16, 2009]"
850,annotation="
851 First posting of expedited RCU to be accepted into -tip.
852"
853}
854
855@unpublished{JoshTriplett2009RPHash
856,Author="Josh Triplett"
857,Title="Scalable concurrent hash tables via relativistic programming"
858,month="September"
859,year="2009"
860,note="Linux Plumbers Conference presentation"
861,annotation="
862 RP fun with hash tables.
863"
864}
865
866@phdthesis{MathieuDesnoyersPhD
867, title = "Low-Impact Operating System Tracing"
868, author = "Mathieu Desnoyers"
869, school = "Ecole Polytechnique de Montr\'{e}al"
870, month = "December"
871, year = 2009
872,note="Available:
873\url{http://www.lttng.org/pub/thesis/desnoyers-dissertation-2009-12.pdf}
874[Viewed December 9, 2009]"
875}
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 51525a30e8b4..cbc180f90194 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -8,13 +8,12 @@ would cause. This list is based on experiences reviewing such patches
8over a rather long period of time, but improvements are always welcome! 8over a rather long period of time, but improvements are always welcome!
9 9
100. Is RCU being applied to a read-mostly situation? If the data 100. Is RCU being applied to a read-mostly situation? If the data
11 structure is updated more than about 10% of the time, then 11 structure is updated more than about 10% of the time, then you
12 you should strongly consider some other approach, unless 12 should strongly consider some other approach, unless detailed
13 detailed performance measurements show that RCU is nonetheless 13 performance measurements show that RCU is nonetheless the right
14 the right tool for the job. Yes, you might think of RCU 14 tool for the job. Yes, RCU does reduce read-side overhead by
15 as simply cutting overhead off of the readers and imposing it 15 increasing write-side overhead, which is exactly why normal uses
16 on the writers. That is exactly why normal uses of RCU will 16 of RCU will do much more reading than updating.
17 do much more reading than updating.
18 17
19 Another exception is where performance is not an issue, and RCU 18 Another exception is where performance is not an issue, and RCU
20 provides a simpler implementation. An example of this situation 19 provides a simpler implementation. An example of this situation
@@ -35,13 +34,13 @@ over a rather long period of time, but improvements are always welcome!
35 34
36 If you choose #b, be prepared to describe how you have handled 35 If you choose #b, be prepared to describe how you have handled
37 memory barriers on weakly ordered machines (pretty much all of 36 memory barriers on weakly ordered machines (pretty much all of
38 them -- even x86 allows reads to be reordered), and be prepared 37 them -- even x86 allows later loads to be reordered to precede
39 to explain why this added complexity is worthwhile. If you 38 earlier stores), and be prepared to explain why this added
40 choose #c, be prepared to explain how this single task does not 39 complexity is worthwhile. If you choose #c, be prepared to
41 become a major bottleneck on big multiprocessor machines (for 40 explain how this single task does not become a major bottleneck on
42 example, if the task is updating information relating to itself 41 big multiprocessor machines (for example, if the task is updating
43 that other tasks can read, there by definition can be no 42 information relating to itself that other tasks can read, there
44 bottleneck). 43 by definition can be no bottleneck).
45 44
462. Do the RCU read-side critical sections make proper use of 452. Do the RCU read-side critical sections make proper use of
47 rcu_read_lock() and friends? These primitives are needed 46 rcu_read_lock() and friends? These primitives are needed
@@ -51,8 +50,10 @@ over a rather long period of time, but improvements are always welcome!
51 actuarial risk of your kernel. 50 actuarial risk of your kernel.
52 51
53 As a rough rule of thumb, any dereference of an RCU-protected 52 As a rough rule of thumb, any dereference of an RCU-protected
54 pointer must be covered by rcu_read_lock() or rcu_read_lock_bh() 53 pointer must be covered by rcu_read_lock(), rcu_read_lock_bh(),
55 or by the appropriate update-side lock. 54 rcu_read_lock_sched(), or by the appropriate update-side lock.
55 Disabling of preemption can serve as rcu_read_lock_sched(), but
56 is less readable.
56 57
573. Does the update code tolerate concurrent accesses? 583. Does the update code tolerate concurrent accesses?
58 59
@@ -62,25 +63,27 @@ over a rather long period of time, but improvements are always welcome!
62 of ways to handle this concurrency, depending on the situation: 63 of ways to handle this concurrency, depending on the situation:
63 64
64 a. Use the RCU variants of the list and hlist update 65 a. Use the RCU variants of the list and hlist update
65 primitives to add, remove, and replace elements on an 66 primitives to add, remove, and replace elements on
66 RCU-protected list. Alternatively, use the RCU-protected 67 an RCU-protected list. Alternatively, use the other
67 trees that have been added to the Linux kernel. 68 RCU-protected data structures that have been added to
69 the Linux kernel.
68 70
69 This is almost always the best approach. 71 This is almost always the best approach.
70 72
71 b. Proceed as in (a) above, but also maintain per-element 73 b. Proceed as in (a) above, but also maintain per-element
72 locks (that are acquired by both readers and writers) 74 locks (that are acquired by both readers and writers)
73 that guard per-element state. Of course, fields that 75 that guard per-element state. Of course, fields that
74 the readers refrain from accessing can be guarded by the 76 the readers refrain from accessing can be guarded by
75 update-side lock. 77 some other lock acquired only by updaters, if desired.
76 78
77 This works quite well, also. 79 This works quite well, also.
78 80
79 c. Make updates appear atomic to readers. For example, 81 c. Make updates appear atomic to readers. For example,
80 pointer updates to properly aligned fields will appear 82 pointer updates to properly aligned fields will
81 atomic, as will individual atomic primitives. Operations 83 appear atomic, as will individual atomic primitives.
82 performed under a lock and sequences of multiple atomic 84 Sequences of perations performed under a lock will -not-
83 primitives will -not- appear to be atomic. 85 appear to be atomic to RCU readers, nor will sequences
86 of multiple atomic primitives.
84 87
85 This can work, but is starting to get a bit tricky. 88 This can work, but is starting to get a bit tricky.
86 89
@@ -98,9 +101,9 @@ over a rather long period of time, but improvements are always welcome!
98 a new structure containing updated values. 101 a new structure containing updated values.
99 102
1004. Weakly ordered CPUs pose special challenges. Almost all CPUs 1034. Weakly ordered CPUs pose special challenges. Almost all CPUs
101 are weakly ordered -- even i386 CPUs allow reads to be reordered. 104 are weakly ordered -- even x86 CPUs allow later loads to be
102 RCU code must take all of the following measures to prevent 105 reordered to precede earlier stores. RCU code must take all of
103 memory-corruption problems: 106 the following measures to prevent memory-corruption problems:
104 107
105 a. Readers must maintain proper ordering of their memory 108 a. Readers must maintain proper ordering of their memory
106 accesses. The rcu_dereference() primitive ensures that 109 accesses. The rcu_dereference() primitive ensures that
@@ -113,14 +116,25 @@ over a rather long period of time, but improvements are always welcome!
113 The rcu_dereference() primitive is also an excellent 116 The rcu_dereference() primitive is also an excellent
114 documentation aid, letting the person reading the code 117 documentation aid, letting the person reading the code
115 know exactly which pointers are protected by RCU. 118 know exactly which pointers are protected by RCU.
116 119 Please note that compilers can also reorder code, and
117 The rcu_dereference() primitive is used by the various 120 they are becoming increasingly aggressive about doing
118 "_rcu()" list-traversal primitives, such as the 121 just that. The rcu_dereference() primitive therefore
119 list_for_each_entry_rcu(). Note that it is perfectly 122 also prevents destructive compiler optimizations.
120 legal (if redundant) for update-side code to use 123
121 rcu_dereference() and the "_rcu()" list-traversal 124 The rcu_dereference() primitive is used by the
122 primitives. This is particularly useful in code 125 various "_rcu()" list-traversal primitives, such
123 that is common to readers and updaters. 126 as the list_for_each_entry_rcu(). Note that it is
127 perfectly legal (if redundant) for update-side code to
128 use rcu_dereference() and the "_rcu()" list-traversal
129 primitives. This is particularly useful in code that
130 is common to readers and updaters. However, lockdep
131 will complain if you access rcu_dereference() outside
132 of an RCU read-side critical section. See lockdep.txt
133 to learn what to do about this.
134
135 Of course, neither rcu_dereference() nor the "_rcu()"
136 list-traversal primitives can substitute for a good
137 concurrency design coordinating among multiple updaters.
124 138
125 b. If the list macros are being used, the list_add_tail_rcu() 139 b. If the list macros are being used, the list_add_tail_rcu()
126 and list_add_rcu() primitives must be used in order 140 and list_add_rcu() primitives must be used in order
@@ -135,11 +149,14 @@ over a rather long period of time, but improvements are always welcome!
135 readers. Similarly, if the hlist macros are being used, 149 readers. Similarly, if the hlist macros are being used,
136 the hlist_del_rcu() primitive is required. 150 the hlist_del_rcu() primitive is required.
137 151
138 The list_replace_rcu() primitive may be used to 152 The list_replace_rcu() and hlist_replace_rcu() primitives
139 replace an old structure with a new one in an 153 may be used to replace an old structure with a new one
140 RCU-protected list. 154 in their respective types of RCU-protected lists.
155
156 d. Rules similar to (4b) and (4c) apply to the "hlist_nulls"
157 type of RCU-protected linked lists.
141 158
142 d. Updates must ensure that initialization of a given 159 e. Updates must ensure that initialization of a given
143 structure happens before pointers to that structure are 160 structure happens before pointers to that structure are
144 publicized. Use the rcu_assign_pointer() primitive 161 publicized. Use the rcu_assign_pointer() primitive
145 when publicizing a pointer to a structure that can 162 when publicizing a pointer to a structure that can
@@ -151,16 +168,31 @@ over a rather long period of time, but improvements are always welcome!
151 it cannot block. 168 it cannot block.
152 169
1536. Since synchronize_rcu() can block, it cannot be called from 1706. Since synchronize_rcu() can block, it cannot be called from
154 any sort of irq context. Ditto for synchronize_sched() and 171 any sort of irq context. The same rule applies for
155 synchronize_srcu(). 172 synchronize_rcu_bh(), synchronize_sched(), synchronize_srcu(),
156 173 synchronize_rcu_expedited(), synchronize_rcu_bh_expedited(),
1577. If the updater uses call_rcu(), then the corresponding readers 174 synchronize_sched_expedite(), and synchronize_srcu_expedited().
158 must use rcu_read_lock() and rcu_read_unlock(). If the updater 175
159 uses call_rcu_bh(), then the corresponding readers must use 176 The expedited forms of these primitives have the same semantics
160 rcu_read_lock_bh() and rcu_read_unlock_bh(). If the updater 177 as the non-expedited forms, but expediting is both expensive
161 uses call_rcu_sched(), then the corresponding readers must 178 and unfriendly to real-time workloads. Use of the expedited
162 disable preemption. Mixing things up will result in confusion 179 primitives should be restricted to rare configuration-change
163 and broken kernels. 180 operations that would not normally be undertaken while a real-time
181 workload is running.
182
1837. If the updater uses call_rcu() or synchronize_rcu(), then the
184 corresponding readers must use rcu_read_lock() and
185 rcu_read_unlock(). If the updater uses call_rcu_bh() or
186 synchronize_rcu_bh(), then the corresponding readers must
187 use rcu_read_lock_bh() and rcu_read_unlock_bh(). If the
188 updater uses call_rcu_sched() or synchronize_sched(), then
189 the corresponding readers must disable preemption, possibly
190 by calling rcu_read_lock_sched() and rcu_read_unlock_sched().
191 If the updater uses synchronize_srcu(), the the corresponding
192 readers must use srcu_read_lock() and srcu_read_unlock(),
193 and with the same srcu_struct. The rules for the expedited
194 primitives are the same as for their non-expedited counterparts.
195 Mixing things up will result in confusion and broken kernels.
164 196
165 One exception to this rule: rcu_read_lock() and rcu_read_unlock() 197 One exception to this rule: rcu_read_lock() and rcu_read_unlock()
166 may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh() 198 may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh()
@@ -212,6 +244,8 @@ over a rather long period of time, but improvements are always welcome!
212 e. Periodically invoke synchronize_rcu(), permitting a limited 244 e. Periodically invoke synchronize_rcu(), permitting a limited
213 number of updates per grace period. 245 number of updates per grace period.
214 246
247 The same cautions apply to call_rcu_bh() and call_rcu_sched().
248
2159. All RCU list-traversal primitives, which include 2499. All RCU list-traversal primitives, which include
216 rcu_dereference(), list_for_each_entry_rcu(), 250 rcu_dereference(), list_for_each_entry_rcu(),
217 list_for_each_continue_rcu(), and list_for_each_safe_rcu(), 251 list_for_each_continue_rcu(), and list_for_each_safe_rcu(),
@@ -219,7 +253,9 @@ over a rather long period of time, but improvements are always welcome!
219 must be protected by appropriate update-side locks. RCU 253 must be protected by appropriate update-side locks. RCU
220 read-side critical sections are delimited by rcu_read_lock() 254 read-side critical sections are delimited by rcu_read_lock()
221 and rcu_read_unlock(), or by similar primitives such as 255 and rcu_read_unlock(), or by similar primitives such as
222 rcu_read_lock_bh() and rcu_read_unlock_bh(). 256 rcu_read_lock_bh() and rcu_read_unlock_bh(), in which case
257 the matching rcu_dereference() primitive must be used in order
258 to keep lockdep happy, in this case, rcu_dereference_bh().
223 259
224 The reason that it is permissible to use RCU list-traversal 260 The reason that it is permissible to use RCU list-traversal
225 primitives when the update-side lock is held is that doing so 261 primitives when the update-side lock is held is that doing so
@@ -229,7 +265,8 @@ over a rather long period of time, but improvements are always welcome!
22910. Conversely, if you are in an RCU read-side critical section, 26510. Conversely, if you are in an RCU read-side critical section,
230 and you don't hold the appropriate update-side lock, you -must- 266 and you don't hold the appropriate update-side lock, you -must-
231 use the "_rcu()" variants of the list macros. Failing to do so 267 use the "_rcu()" variants of the list macros. Failing to do so
232 will break Alpha and confuse people reading your code. 268 will break Alpha, cause aggressive compilers to generate bad code,
269 and confuse people trying to read your code.
233 270
23411. Note that synchronize_rcu() -only- guarantees to wait until 27111. Note that synchronize_rcu() -only- guarantees to wait until
235 all currently executing rcu_read_lock()-protected RCU read-side 272 all currently executing rcu_read_lock()-protected RCU read-side
@@ -239,15 +276,21 @@ over a rather long period of time, but improvements are always welcome!
239 rcu_read_lock()-protected read-side critical sections, do -not- 276 rcu_read_lock()-protected read-side critical sections, do -not-
240 use synchronize_rcu(). 277 use synchronize_rcu().
241 278
242 If you want to wait for some of these other things, you might 279 Similarly, disabling preemption is not an acceptable substitute
243 instead need to use synchronize_irq() or synchronize_sched(). 280 for rcu_read_lock(). Code that attempts to use preemption
281 disabling where it should be using rcu_read_lock() will break
282 in real-time kernel builds.
283
284 If you want to wait for interrupt handlers, NMI handlers, and
285 code under the influence of preempt_disable(), you instead
286 need to use synchronize_irq() or synchronize_sched().
244 287
24512. Any lock acquired by an RCU callback must be acquired elsewhere 28812. Any lock acquired by an RCU callback must be acquired elsewhere
246 with softirq disabled, e.g., via spin_lock_irqsave(), 289 with softirq disabled, e.g., via spin_lock_irqsave(),
247 spin_lock_bh(), etc. Failing to disable irq on a given 290 spin_lock_bh(), etc. Failing to disable irq on a given
248 acquisition of that lock will result in deadlock as soon as the 291 acquisition of that lock will result in deadlock as soon as
249 RCU callback happens to interrupt that acquisition's critical 292 the RCU softirq handler happens to run your RCU callback while
250 section. 293 interrupting that acquisition's critical section.
251 294
25213. RCU callbacks can be and are executed in parallel. In many cases, 29513. RCU callbacks can be and are executed in parallel. In many cases,
253 the callback code simply wrappers around kfree(), so that this 296 the callback code simply wrappers around kfree(), so that this
@@ -265,29 +308,30 @@ over a rather long period of time, but improvements are always welcome!
265 not the case, a self-spawning RCU callback would prevent the 308 not the case, a self-spawning RCU callback would prevent the
266 victim CPU from ever going offline.) 309 victim CPU from ever going offline.)
267 310
26814. SRCU (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu()) 31114. SRCU (srcu_read_lock(), srcu_read_unlock(), srcu_dereference(),
269 may only be invoked from process context. Unlike other forms of 312 synchronize_srcu(), and synchronize_srcu_expedited()) may only
270 RCU, it -is- permissible to block in an SRCU read-side critical 313 be invoked from process context. Unlike other forms of RCU, it
271 section (demarked by srcu_read_lock() and srcu_read_unlock()), 314 -is- permissible to block in an SRCU read-side critical section
272 hence the "SRCU": "sleepable RCU". Please note that if you 315 (demarked by srcu_read_lock() and srcu_read_unlock()), hence the
273 don't need to sleep in read-side critical sections, you should 316 "SRCU": "sleepable RCU". Please note that if you don't need
274 be using RCU rather than SRCU, because RCU is almost always 317 to sleep in read-side critical sections, you should be using
275 faster and easier to use than is SRCU. 318 RCU rather than SRCU, because RCU is almost always faster and
319 easier to use than is SRCU.
276 320
277 Also unlike other forms of RCU, explicit initialization 321 Also unlike other forms of RCU, explicit initialization
278 and cleanup is required via init_srcu_struct() and 322 and cleanup is required via init_srcu_struct() and
279 cleanup_srcu_struct(). These are passed a "struct srcu_struct" 323 cleanup_srcu_struct(). These are passed a "struct srcu_struct"
280 that defines the scope of a given SRCU domain. Once initialized, 324 that defines the scope of a given SRCU domain. Once initialized,
281 the srcu_struct is passed to srcu_read_lock(), srcu_read_unlock() 325 the srcu_struct is passed to srcu_read_lock(), srcu_read_unlock()
282 and synchronize_srcu(). A given synchronize_srcu() waits only 326 synchronize_srcu(), and synchronize_srcu_expedited(). A given
283 for SRCU read-side critical sections governed by srcu_read_lock() 327 synchronize_srcu() waits only for SRCU read-side critical
284 and srcu_read_unlock() calls that have been passd the same 328 sections governed by srcu_read_lock() and srcu_read_unlock()
285 srcu_struct. This property is what makes sleeping read-side 329 calls that have been passed the same srcu_struct. This property
286 critical sections tolerable -- a given subsystem delays only 330 is what makes sleeping read-side critical sections tolerable --
287 its own updates, not those of other subsystems using SRCU. 331 a given subsystem delays only its own updates, not those of other
288 Therefore, SRCU is less prone to OOM the system than RCU would 332 subsystems using SRCU. Therefore, SRCU is less prone to OOM the
289 be if RCU's read-side critical sections were permitted to 333 system than RCU would be if RCU's read-side critical sections
290 sleep. 334 were permitted to sleep.
291 335
292 The ability to sleep in read-side critical sections does not 336 The ability to sleep in read-side critical sections does not
293 come for free. First, corresponding srcu_read_lock() and 337 come for free. First, corresponding srcu_read_lock() and
@@ -311,12 +355,12 @@ over a rather long period of time, but improvements are always welcome!
311 destructive operation, and -only- -then- invoke call_rcu(), 355 destructive operation, and -only- -then- invoke call_rcu(),
312 synchronize_rcu(), or friends. 356 synchronize_rcu(), or friends.
313 357
314 Because these primitives only wait for pre-existing readers, 358 Because these primitives only wait for pre-existing readers, it
315 it is the caller's responsibility to guarantee safety to 359 is the caller's responsibility to guarantee that any subsequent
316 any subsequent readers. 360 readers will execute safely.
317 361
31816. The various RCU read-side primitives do -not- contain memory 36216. The various RCU read-side primitives do -not- necessarily contain
319 barriers. The CPU (and in some cases, the compiler) is free 363 memory barriers. You should therefore plan for the CPU
320 to reorder code into and out of RCU read-side critical sections. 364 and the compiler to freely reorder code into and out of RCU
321 It is the responsibility of the RCU update-side primitives to 365 read-side critical sections. It is the responsibility of the
322 deal with this. 366 RCU update-side primitives to deal with this.
diff --git a/Documentation/RCU/lockdep.txt b/Documentation/RCU/lockdep.txt
new file mode 100644
index 000000000000..fe24b58627bd
--- /dev/null
+++ b/Documentation/RCU/lockdep.txt
@@ -0,0 +1,67 @@
1RCU and lockdep checking
2
3All flavors of RCU have lockdep checking available, so that lockdep is
4aware of when each task enters and leaves any flavor of RCU read-side
5critical section. Each flavor of RCU is tracked separately (but note
6that this is not the case in 2.6.32 and earlier). This allows lockdep's
7tracking to include RCU state, which can sometimes help when debugging
8deadlocks and the like.
9
10In addition, RCU provides the following primitives that check lockdep's
11state:
12
13 rcu_read_lock_held() for normal RCU.
14 rcu_read_lock_bh_held() for RCU-bh.
15 rcu_read_lock_sched_held() for RCU-sched.
16 srcu_read_lock_held() for SRCU.
17
18These functions are conservative, and will therefore return 1 if they
19aren't certain (for example, if CONFIG_DEBUG_LOCK_ALLOC is not set).
20This prevents things like WARN_ON(!rcu_read_lock_held()) from giving false
21positives when lockdep is disabled.
22
23In addition, a separate kernel config parameter CONFIG_PROVE_RCU enables
24checking of rcu_dereference() primitives:
25
26 rcu_dereference(p):
27 Check for RCU read-side critical section.
28 rcu_dereference_bh(p):
29 Check for RCU-bh read-side critical section.
30 rcu_dereference_sched(p):
31 Check for RCU-sched read-side critical section.
32 srcu_dereference(p, sp):
33 Check for SRCU read-side critical section.
34 rcu_dereference_check(p, c):
35 Use explicit check expression "c".
36 rcu_dereference_raw(p)
37 Don't check. (Use sparingly, if at all.)
38
39The rcu_dereference_check() check expression can be any boolean
40expression, but would normally include one of the rcu_read_lock_held()
41family of functions and a lockdep expression. However, any boolean
42expression can be used. For a moderately ornate example, consider
43the following:
44
45 file = rcu_dereference_check(fdt->fd[fd],
46 rcu_read_lock_held() ||
47 lockdep_is_held(&files->file_lock) ||
48 atomic_read(&files->count) == 1);
49
50This expression picks up the pointer "fdt->fd[fd]" in an RCU-safe manner,
51and, if CONFIG_PROVE_RCU is configured, verifies that this expression
52is used in:
53
541. An RCU read-side critical section, or
552. with files->file_lock held, or
563. on an unshared files_struct.
57
58In case (1), the pointer is picked up in an RCU-safe manner for vanilla
59RCU read-side critical sections, in case (2) the ->file_lock prevents
60any change from taking place, and finally, in case (3) the current task
61is the only task accessing the file_struct, again preventing any change
62from taking place.
63
64There are currently only "universal" versions of the rcu_assign_pointer()
65and RCU list-/tree-traversal primitives, which do not (yet) check for
66being in an RCU read-side critical section. In the future, separate
67versions of these primitives might be created.
diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt
index 2a23523ce471..31852705b586 100644
--- a/Documentation/RCU/rcu.txt
+++ b/Documentation/RCU/rcu.txt
@@ -75,6 +75,8 @@ o I hear that RCU is patented? What is with that?
75 search for the string "Patent" in RTFP.txt to find them. 75 search for the string "Patent" in RTFP.txt to find them.
76 Of these, one was allowed to lapse by the assignee, and the 76 Of these, one was allowed to lapse by the assignee, and the
77 others have been contributed to the Linux kernel under GPL. 77 others have been contributed to the Linux kernel under GPL.
78 There are now also LGPL implementations of user-level RCU
79 available (http://lttng.org/?q=node/18).
78 80
79o I hear that RCU needs work in order to support realtime kernels? 81o I hear that RCU needs work in order to support realtime kernels?
80 82
@@ -91,48 +93,4 @@ o Where can I find more information on RCU?
91 93
92o What are all these files in this directory? 94o What are all these files in this directory?
93 95
94 96 See 00-INDEX for the list.
95 NMI-RCU.txt
96
97 Describes how to use RCU to implement dynamic
98 NMI handlers, which can be revectored on the fly,
99 without rebooting.
100
101 RTFP.txt
102
103 List of RCU-related publications and web sites.
104
105 UP.txt
106
107 Discussion of RCU usage in UP kernels.
108
109 arrayRCU.txt
110
111 Describes how to use RCU to protect arrays, with
112 resizeable arrays whose elements reference other
113 data structures being of the most interest.
114
115 checklist.txt
116
117 Lists things to check for when inspecting code that
118 uses RCU.
119
120 listRCU.txt
121
122 Describes how to use RCU to protect linked lists.
123 This is the simplest and most common use of RCU
124 in the Linux kernel.
125
126 rcu.txt
127
128 You are reading it!
129
130 rcuref.txt
131
132 Describes how to combine use of reference counts
133 with RCU.
134
135 whatisRCU.txt
136
137 Overview of how the RCU implementation works. Along
138 the way, presents a conceptual view of RCU.
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
new file mode 100644
index 000000000000..1423d2570d78
--- /dev/null
+++ b/Documentation/RCU/stallwarn.txt
@@ -0,0 +1,58 @@
1Using RCU's CPU Stall Detector
2
3The CONFIG_RCU_CPU_STALL_DETECTOR kernel config parameter enables
4RCU's CPU stall detector, which detects conditions that unduly delay
5RCU grace periods. The stall detector's idea of what constitutes
6"unduly delayed" is controlled by a pair of C preprocessor macros:
7
8RCU_SECONDS_TILL_STALL_CHECK
9
10 This macro defines the period of time that RCU will wait from
11 the beginning of a grace period until it issues an RCU CPU
12 stall warning. It is normally ten seconds.
13
14RCU_SECONDS_TILL_STALL_RECHECK
15
16 This macro defines the period of time that RCU will wait after
17 issuing a stall warning until it issues another stall warning.
18 It is normally set to thirty seconds.
19
20RCU_STALL_RAT_DELAY
21
22 The CPU stall detector tries to make the offending CPU rat on itself,
23 as this often gives better-quality stack traces. However, if
24 the offending CPU does not detect its own stall in the number
25 of jiffies specified by RCU_STALL_RAT_DELAY, then other CPUs will
26 complain. This is normally set to two jiffies.
27
28The following problems can result in an RCU CPU stall warning:
29
30o A CPU looping in an RCU read-side critical section.
31
32o A CPU looping with interrupts disabled.
33
34o A CPU looping with preemption disabled.
35
36o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel
37 without invoking schedule().
38
39o A bug in the RCU implementation.
40
41o A hardware failure. This is quite unlikely, but has occurred
42 at least once in a former life. A CPU failed in a running system,
43 becoming unresponsive, but not causing an immediate crash.
44 This resulted in a series of RCU CPU stall warnings, eventually
45 leading the realization that the CPU had failed.
46
47The RCU, RCU-sched, and RCU-bh implementations have CPU stall warning.
48SRCU does not do so directly, but its calls to synchronize_sched() will
49result in RCU-sched detecting any CPU stalls that might be occurring.
50
51To diagnose the cause of the stall, inspect the stack traces. The offending
52function will usually be near the top of the stack. If you have a series
53of stall warnings from a single extended stall, comparing the stack traces
54can often help determine where the stall is occurring, which will usually
55be in the function nearest the top of the stack that stays the same from
56trace to trace.
57
58RCU bugs can often be debugged with the help of CONFIG_RCU_TRACE.
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 9dba3bb90e60..0e50bc2aa1e2 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -30,6 +30,18 @@ MODULE PARAMETERS
30 30
31This module has the following parameters: 31This module has the following parameters:
32 32
33fqs_duration Duration (in microseconds) of artificially induced bursts
34 of force_quiescent_state() invocations. In RCU
35 implementations having force_quiescent_state(), these
36 bursts help force races between forcing a given grace
37 period and that grace period ending on its own.
38
39fqs_holdoff Holdoff time (in microseconds) between consecutive calls
40 to force_quiescent_state() within a burst.
41
42fqs_stutter Wait time (in seconds) between consecutive bursts
43 of calls to force_quiescent_state().
44
33irqreaders Says to invoke RCU readers from irq level. This is currently 45irqreaders Says to invoke RCU readers from irq level. This is currently
34 done via timers. Defaults to "1" for variants of RCU that 46 done via timers. Defaults to "1" for variants of RCU that
35 permit this. (Or, more accurately, variants of RCU that do 47 permit this. (Or, more accurately, variants of RCU that do
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index d542ca243b80..1dc00ee97163 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -323,14 +323,17 @@ used as follows:
323 Defer Protect 323 Defer Protect
324 324
325a. synchronize_rcu() rcu_read_lock() / rcu_read_unlock() 325a. synchronize_rcu() rcu_read_lock() / rcu_read_unlock()
326 call_rcu() 326 call_rcu() rcu_dereference()
327 327
328b. call_rcu_bh() rcu_read_lock_bh() / rcu_read_unlock_bh() 328b. call_rcu_bh() rcu_read_lock_bh() / rcu_read_unlock_bh()
329 rcu_dereference_bh()
329 330
330c. synchronize_sched() preempt_disable() / preempt_enable() 331c. synchronize_sched() rcu_read_lock_sched() / rcu_read_unlock_sched()
332 preempt_disable() / preempt_enable()
331 local_irq_save() / local_irq_restore() 333 local_irq_save() / local_irq_restore()
332 hardirq enter / hardirq exit 334 hardirq enter / hardirq exit
333 NMI enter / NMI exit 335 NMI enter / NMI exit
336 rcu_dereference_sched()
334 337
335These three mechanisms are used as follows: 338These three mechanisms are used as follows:
336 339
@@ -780,9 +783,8 @@ Linux-kernel source code, but it helps to have a full list of the
780APIs, since there does not appear to be a way to categorize them 783APIs, since there does not appear to be a way to categorize them
781in docbook. Here is the list, by category. 784in docbook. Here is the list, by category.
782 785
783RCU pointer/list traversal: 786RCU list traversal:
784 787
785 rcu_dereference
786 list_for_each_entry_rcu 788 list_for_each_entry_rcu
787 hlist_for_each_entry_rcu 789 hlist_for_each_entry_rcu
788 hlist_nulls_for_each_entry_rcu 790 hlist_nulls_for_each_entry_rcu
@@ -808,7 +810,7 @@ RCU: Critical sections Grace period Barrier
808 810
809 rcu_read_lock synchronize_net rcu_barrier 811 rcu_read_lock synchronize_net rcu_barrier
810 rcu_read_unlock synchronize_rcu 812 rcu_read_unlock synchronize_rcu
811 synchronize_rcu_expedited 813 rcu_dereference synchronize_rcu_expedited
812 call_rcu 814 call_rcu
813 815
814 816
@@ -816,7 +818,7 @@ bh: Critical sections Grace period Barrier
816 818
817 rcu_read_lock_bh call_rcu_bh rcu_barrier_bh 819 rcu_read_lock_bh call_rcu_bh rcu_barrier_bh
818 rcu_read_unlock_bh synchronize_rcu_bh 820 rcu_read_unlock_bh synchronize_rcu_bh
819 synchronize_rcu_bh_expedited 821 rcu_dereference_bh synchronize_rcu_bh_expedited
820 822
821 823
822sched: Critical sections Grace period Barrier 824sched: Critical sections Grace period Barrier
@@ -825,12 +827,14 @@ sched: Critical sections Grace period Barrier
825 rcu_read_unlock_sched call_rcu_sched 827 rcu_read_unlock_sched call_rcu_sched
826 [preempt_disable] synchronize_sched_expedited 828 [preempt_disable] synchronize_sched_expedited
827 [and friends] 829 [and friends]
830 rcu_dereference_sched
828 831
829 832
830SRCU: Critical sections Grace period Barrier 833SRCU: Critical sections Grace period Barrier
831 834
832 srcu_read_lock synchronize_srcu N/A 835 srcu_read_lock synchronize_srcu N/A
833 srcu_read_unlock synchronize_srcu_expedited 836 srcu_read_unlock synchronize_srcu_expedited
837 srcu_dereference
834 838
835SRCU: Initialization/cleanup 839SRCU: Initialization/cleanup
836 init_srcu_struct 840 init_srcu_struct
diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt
index da42ab414c48..b231414bb8bc 100644
--- a/Documentation/cachetlb.txt
+++ b/Documentation/cachetlb.txt
@@ -377,3 +377,27 @@ maps this page at its virtual address.
377 All the functionality of flush_icache_page can be implemented in 377 All the functionality of flush_icache_page can be implemented in
378 flush_dcache_page and update_mmu_cache. In 2.7 the hope is to 378 flush_dcache_page and update_mmu_cache. In 2.7 the hope is to
379 remove this interface completely. 379 remove this interface completely.
380
381The final category of APIs is for I/O to deliberately aliased address
382ranges inside the kernel. Such aliases are set up by use of the
383vmap/vmalloc API. Since kernel I/O goes via physical pages, the I/O
384subsystem assumes that the user mapping and kernel offset mapping are
385the only aliases. This isn't true for vmap aliases, so anything in
386the kernel trying to do I/O to vmap areas must manually manage
387coherency. It must do this by flushing the vmap range before doing
388I/O and invalidating it after the I/O returns.
389
390 void flush_kernel_vmap_range(void *vaddr, int size)
391 flushes the kernel cache for a given virtual address range in
392 the vmap area. This is to make sure that any data the kernel
393 modified in the vmap range is made visible to the physical
394 page. The design is to make this area safe to perform I/O on.
395 Note that this API does *not* also flush the offset map alias
396 of the area.
397
398 void invalidate_kernel_vmap_range(void *vaddr, int size) invalidates
399 the cache for a given virtual address range in the vmap area
400 which prevents the processor from making the cache stale by
401 speculatively reading data while the I/O was occurring to the
402 physical pages. This is only necessary for data reads into the
403 vmap area.
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 3ad6acead949..d9bcffd59433 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -69,7 +69,6 @@ av_permissions.h
69bbootsect 69bbootsect
70bin2c 70bin2c
71binkernel.spec 71binkernel.spec
72binoffset
73bootsect 72bootsect
74bounds.h 73bounds.h
75bsetup 74bsetup
diff --git a/Documentation/dvb/get_dvb_firmware b/Documentation/dvb/get_dvb_firmware
index 14b7b5a3bcb9..239cbdbf4d12 100644
--- a/Documentation/dvb/get_dvb_firmware
+++ b/Documentation/dvb/get_dvb_firmware
@@ -26,7 +26,7 @@ use IO::Handle;
26 "dec3000s", "vp7041", "dibusb", "nxt2002", "nxt2004", 26 "dec3000s", "vp7041", "dibusb", "nxt2002", "nxt2004",
27 "or51211", "or51132_qam", "or51132_vsb", "bluebird", 27 "or51211", "or51132_qam", "or51132_vsb", "bluebird",
28 "opera1", "cx231xx", "cx18", "cx23885", "pvrusb2", "mpc718", 28 "opera1", "cx231xx", "cx18", "cx23885", "pvrusb2", "mpc718",
29 "af9015"); 29 "af9015", "ngene");
30 30
31# Check args 31# Check args
32syntax() if (scalar(@ARGV) != 1); 32syntax() if (scalar(@ARGV) != 1);
@@ -39,7 +39,7 @@ for ($i=0; $i < scalar(@components); $i++) {
39 die $@ if $@; 39 die $@ if $@;
40 print STDERR <<EOF; 40 print STDERR <<EOF;
41Firmware(s) $outfile extracted successfully. 41Firmware(s) $outfile extracted successfully.
42Now copy it(they) to either /usr/lib/hotplug/firmware or /lib/firmware 42Now copy it(them) to either /usr/lib/hotplug/firmware or /lib/firmware
43(depending on configuration of firmware hotplug). 43(depending on configuration of firmware hotplug).
44EOF 44EOF
45 exit(0); 45 exit(0);
@@ -549,6 +549,24 @@ sub af9015 {
549 close INFILE; 549 close INFILE;
550} 550}
551 551
552sub ngene {
553 my $url = "http://www.digitaldevices.de/download/";
554 my $file1 = "ngene_15.fw";
555 my $hash1 = "d798d5a757121174f0dbc5f2833c0c85";
556 my $file2 = "ngene_17.fw";
557 my $hash2 = "26b687136e127b8ac24b81e0eeafc20b";
558
559 checkstandard();
560
561 wgetfile($file1, $url . $file1);
562 verify($file1, $hash1);
563
564 wgetfile($file2, $url . $file2);
565 verify($file2, $hash2);
566
567 "$file1, $file2";
568}
569
552# --------------------------------------------------------------- 570# ---------------------------------------------------------------
553# Utilities 571# Utilities
554 572
@@ -667,6 +685,7 @@ sub delzero{
667sub syntax() { 685sub syntax() {
668 print STDERR "syntax: get_dvb_firmware <component>\n"; 686 print STDERR "syntax: get_dvb_firmware <component>\n";
669 print STDERR "Supported components:\n"; 687 print STDERR "Supported components:\n";
688 @components = sort @components;
670 for($i=0; $i < scalar(@components); $i++) { 689 for($i=0; $i < scalar(@components); $i++) {
671 print STDERR "\t" . $components[$i] . "\n"; 690 print STDERR "\t" . $components[$i] . "\n";
672 } 691 }
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 0a46833c1b76..ea401495528d 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -6,21 +6,6 @@ be removed from this file.
6 6
7--------------------------- 7---------------------------
8 8
9What: USER_SCHED
10When: 2.6.34
11
12Why: USER_SCHED was implemented as a proof of concept for group scheduling.
13 The effect of USER_SCHED can already be achieved from userspace with
14 the help of libcgroup. The removal of USER_SCHED will also simplify
15 the scheduler code with the removal of one major ifdef. There are also
16 issues USER_SCHED has with USER_NS. A decision was taken not to fix
17 those and instead remove USER_SCHED. Also new group scheduling
18 features will not be implemented for USER_SCHED.
19
20Who: Dhaval Giani <dhaval@linux.vnet.ibm.com>
21
22---------------------------
23
24What: PRISM54 9What: PRISM54
25When: 2.6.34 10When: 2.6.34
26 11
@@ -64,6 +49,17 @@ Who: Robin Getz <rgetz@blackfin.uclinux.org> & Matt Mackall <mpm@selenic.com>
64 49
65--------------------------- 50---------------------------
66 51
52What: Deprecated snapshot ioctls
53When: 2.6.36
54
55Why: The ioctls in kernel/power/user.c were marked as deprecated long time
56 ago. Now they notify users about that so that they need to replace
57 their userspace. After some more time, remove them completely.
58
59Who: Jiri Slaby <jirislaby@gmail.com>
60
61---------------------------
62
67What: The ieee80211_regdom module parameter 63What: The ieee80211_regdom module parameter
68When: March 2010 / desktop catchup 64When: March 2010 / desktop catchup
69 65
diff --git a/Documentation/filesystems/dentry-locking.txt b/Documentation/filesystems/dentry-locking.txt
index 4c0c575a4012..79334ed5daa7 100644
--- a/Documentation/filesystems/dentry-locking.txt
+++ b/Documentation/filesystems/dentry-locking.txt
@@ -62,7 +62,8 @@ changes are :
622. Insertion of a dentry into the hash table is done using 622. Insertion of a dentry into the hash table is done using
63 hlist_add_head_rcu() which take care of ordering the writes - the 63 hlist_add_head_rcu() which take care of ordering the writes - the
64 writes to the dentry must be visible before the dentry is 64 writes to the dentry must be visible before the dentry is
65 inserted. This works in conjunction with hlist_for_each_rcu() while 65 inserted. This works in conjunction with hlist_for_each_rcu(),
66 which has since been replaced by hlist_for_each_entry_rcu(), while
66 walking the hash chain. The only requirement is that all 67 walking the hash chain. The only requirement is that all
67 initialization to the dentry must be done before 68 initialization to the dentry must be done before
68 hlist_add_head_rcu() since we don't have dcache_lock protection 69 hlist_add_head_rcu() since we don't have dcache_lock protection
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e7848a0d99eb..8c666d80f0e7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1738,6 +1738,9 @@ and is between 256 and 4096 characters. It is defined in the file
1738 nomfgpt [X86-32] Disable Multi-Function General Purpose 1738 nomfgpt [X86-32] Disable Multi-Function General Purpose
1739 Timer usage (for AMD Geode machines). 1739 Timer usage (for AMD Geode machines).
1740 1740
1741 nopat [X86] Disable PAT (page attribute table extension of
1742 pagetables) support.
1743
1741 norandmaps Don't use address space randomization. Equivalent to 1744 norandmaps Don't use address space randomization. Equivalent to
1742 echo 0 > /proc/sys/kernel/randomize_va_space 1745 echo 0 > /proc/sys/kernel/randomize_va_space
1743 1746
@@ -1948,8 +1951,12 @@ and is between 256 and 4096 characters. It is defined in the file
1948 IRQ routing is enabled. 1951 IRQ routing is enabled.
1949 noacpi [X86] Do not use ACPI for IRQ routing 1952 noacpi [X86] Do not use ACPI for IRQ routing
1950 or for PCI scanning. 1953 or for PCI scanning.
1951 use_crs [X86] Use _CRS for PCI resource 1954 use_crs [X86] Use PCI host bridge window information
1952 allocation. 1955 from ACPI. On BIOSes from 2008 or later, this
1956 is enabled by default. If you need to use this,
1957 please report a bug.
1958 nocrs [X86] Ignore PCI host bridge windows from ACPI.
1959 If you need to use this, please report a bug.
1953 routeirq Do IRQ routing for all PCI devices. 1960 routeirq Do IRQ routing for all PCI devices.
1954 This is normally done in pci_enable_device(), 1961 This is normally done in pci_enable_device(),
1955 so this option is a temporary workaround 1962 so this option is a temporary workaround
@@ -1998,6 +2005,14 @@ and is between 256 and 4096 characters. It is defined in the file
1998 force Enable ASPM even on devices that claim not to support it. 2005 force Enable ASPM even on devices that claim not to support it.
1999 WARNING: Forcing ASPM on may cause system lockups. 2006 WARNING: Forcing ASPM on may cause system lockups.
2000 2007
2008 pcie_pme= [PCIE,PM] Native PCIe PME signaling options:
2009 off Do not use native PCIe PME signaling.
2010 force Use native PCIe PME signaling even if the BIOS refuses
2011 to allow the kernel to control the relevant PCIe config
2012 registers.
2013 nomsi Do not use MSI for native PCIe PME signaling (this makes
2014 all PCIe root ports use INTx for everything).
2015
2001 pcmv= [HW,PCMCIA] BadgePAD 4 2016 pcmv= [HW,PCMCIA] BadgePAD 4
2002 2017
2003 pd. [PARIDE] 2018 pd. [PARIDE]
@@ -2703,6 +2718,13 @@ and is between 256 and 4096 characters. It is defined in the file
2703 medium is write-protected). 2718 medium is write-protected).
2704 Example: quirks=0419:aaf5:rl,0421:0433:rc 2719 Example: quirks=0419:aaf5:rl,0421:0433:rc
2705 2720
2721 userpte=
2722 [X86] Flags controlling user PTE allocations.
2723
2724 nohigh = do not allocate PTE pages in
2725 HIGHMEM regardless of setting
2726 of CONFIG_HIGHPTE.
2727
2706 vdso= [X86,SH] 2728 vdso= [X86,SH]
2707 vdso=2: enable compat VDSO (default with COMPAT_VDSO) 2729 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2708 vdso=1: enable VDSO (default) 2730 vdso=1: enable VDSO (default)
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 42208511b5c0..3119f5db75bd 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -34,7 +34,6 @@
34#include <sys/uio.h> 34#include <sys/uio.h>
35#include <termios.h> 35#include <termios.h>
36#include <getopt.h> 36#include <getopt.h>
37#include <zlib.h>
38#include <assert.h> 37#include <assert.h>
39#include <sched.h> 38#include <sched.h>
40#include <limits.h> 39#include <limits.h>
diff --git a/Documentation/pcmcia/locking.txt b/Documentation/pcmcia/locking.txt
new file mode 100644
index 000000000000..68f622bc4064
--- /dev/null
+++ b/Documentation/pcmcia/locking.txt
@@ -0,0 +1,118 @@
1This file explains the locking and exclusion scheme used in the PCCARD
2and PCMCIA subsystems.
3
4
5A) Overview, Locking Hierarchy:
6===============================
7
8pcmcia_socket_list_rwsem - protects only the list of sockets
9- skt_mutex - serializes card insert / ejection
10 - ops_mutex - serializes socket operation
11
12
13B) Exclusion
14============
15
16The following functions and callbacks to struct pcmcia_socket must
17be called with "skt_mutex" held:
18
19 socket_detect_change()
20 send_event()
21 socket_reset()
22 socket_shutdown()
23 socket_setup()
24 socket_remove()
25 socket_insert()
26 socket_early_resume()
27 socket_late_resume()
28 socket_resume()
29 socket_suspend()
30
31 struct pcmcia_callback *callback
32
33The following functions and callbacks to struct pcmcia_socket must
34be called with "ops_mutex" held:
35
36 socket_reset()
37 socket_setup()
38
39 struct pccard_operations *ops
40 struct pccard_resource_ops *resource_ops;
41
42Note that send_event() and struct pcmcia_callback *callback must not be
43called with "ops_mutex" held.
44
45
46C) Protection
47=============
48
491. Global Data:
50---------------
51struct list_head pcmcia_socket_list;
52
53protected by pcmcia_socket_list_rwsem;
54
55
562. Per-Socket Data:
57-------------------
58The resource_ops and their data are protected by ops_mutex.
59
60The "main" struct pcmcia_socket is protected as follows (read-only fields
61or single-use fields not mentioned):
62
63- by pcmcia_socket_list_rwsem:
64 struct list_head socket_list;
65
66- by thread_lock:
67 unsigned int thread_events;
68
69- by skt_mutex:
70 u_int suspended_state;
71 void (*tune_bridge);
72 struct pcmcia_callback *callback;
73 int resume_status;
74
75- by ops_mutex:
76 socket_state_t socket;
77 u_int state;
78 u_short lock_count;
79 pccard_mem_map cis_mem;
80 void __iomem *cis_virt;
81 struct { } irq;
82 io_window_t io[];
83 pccard_mem_map win[];
84 struct list_head cis_cache;
85 size_t fake_cis_len;
86 u8 *fake_cis;
87 u_int irq_mask;
88 void (*zoom_video);
89 int (*power_hook);
90 u8 resource...;
91 struct list_head devices_list;
92 u8 device_count;
93 struct pcmcia_state;
94
95
963. Per PCMCIA-device Data:
97--------------------------
98
99The "main" struct pcmcia_devie is protected as follows (read-only fields
100or single-use fields not mentioned):
101
102
103- by pcmcia_socket->ops_mutex:
104 struct list_head socket_device_list;
105 struct config_t *function_config;
106 u16 _irq:1;
107 u16 _io:1;
108 u16 _win:4;
109 u16 _locked:1;
110 u16 allow_func_id_match:1;
111 u16 suspended:1;
112 u16 _removed:1;
113
114- by the PCMCIA driver:
115 io_req_t io;
116 irq_req_t irq;
117 config_req_t conf;
118 window_handle_t win;
diff --git a/Documentation/powerpc/dts-bindings/fsl/mpc5121-psc.txt b/Documentation/powerpc/dts-bindings/fsl/mpc5121-psc.txt
new file mode 100644
index 000000000000..8832e8798912
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/fsl/mpc5121-psc.txt
@@ -0,0 +1,70 @@
1MPC5121 PSC Device Tree Bindings
2
3PSC in UART mode
4----------------
5
6For PSC in UART mode the needed PSC serial devices
7are specified by fsl,mpc5121-psc-uart nodes in the
8fsl,mpc5121-immr SoC node. Additionally the PSC FIFO
9Controller node fsl,mpc5121-psc-fifo is requered there:
10
11fsl,mpc5121-psc-uart nodes
12--------------------------
13
14Required properties :
15 - compatible : Should contain "fsl,mpc5121-psc-uart" and "fsl,mpc5121-psc"
16 - cell-index : Index of the PSC in hardware
17 - reg : Offset and length of the register set for the PSC device
18 - interrupts : <a b> where a is the interrupt number of the
19 PSC FIFO Controller and b is a field that represents an
20 encoding of the sense and level information for the interrupt.
21 - interrupt-parent : the phandle for the interrupt controller that
22 services interrupts for this device.
23
24Recommended properties :
25 - fsl,rx-fifo-size : the size of the RX fifo slice (a multiple of 4)
26 - fsl,tx-fifo-size : the size of the TX fifo slice (a multiple of 4)
27
28
29fsl,mpc5121-psc-fifo node
30-------------------------
31
32Required properties :
33 - compatible : Should be "fsl,mpc5121-psc-fifo"
34 - reg : Offset and length of the register set for the PSC
35 FIFO Controller
36 - interrupts : <a b> where a is the interrupt number of the
37 PSC FIFO Controller and b is a field that represents an
38 encoding of the sense and level information for the interrupt.
39 - interrupt-parent : the phandle for the interrupt controller that
40 services interrupts for this device.
41
42
43Example for a board using PSC0 and PSC1 devices in serial mode:
44
45serial@11000 {
46 compatible = "fsl,mpc5121-psc-uart", "fsl,mpc5121-psc";
47 cell-index = <0>;
48 reg = <0x11000 0x100>;
49 interrupts = <40 0x8>;
50 interrupt-parent = < &ipic >;
51 fsl,rx-fifo-size = <16>;
52 fsl,tx-fifo-size = <16>;
53};
54
55serial@11100 {
56 compatible = "fsl,mpc5121-psc-uart", "fsl,mpc5121-psc";
57 cell-index = <1>;
58 reg = <0x11100 0x100>;
59 interrupts = <40 0x8>;
60 interrupt-parent = < &ipic >;
61 fsl,rx-fifo-size = <16>;
62 fsl,tx-fifo-size = <16>;
63};
64
65pscfifo@11f00 {
66 compatible = "fsl,mpc5121-psc-fifo";
67 reg = <0x11f00 0x100>;
68 interrupts = <40 0x8>;
69 interrupt-parent = < &ipic >;
70};
diff --git a/Documentation/powerpc/dts-bindings/fsl/spi.txt b/Documentation/powerpc/dts-bindings/fsl/spi.txt
index e7d9a344c4f4..80510c018eea 100644
--- a/Documentation/powerpc/dts-bindings/fsl/spi.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/spi.txt
@@ -13,6 +13,11 @@ Required properties:
13- interrupt-parent : the phandle for the interrupt controller that 13- interrupt-parent : the phandle for the interrupt controller that
14 services interrupts for this device. 14 services interrupts for this device.
15 15
16Optional properties:
17- gpios : specifies the gpio pins to be used for chipselects.
18 The gpios will be referred to as reg = <index> in the SPI child nodes.
19 If unspecified, a single SPI device without a chip select can be used.
20
16Example: 21Example:
17 spi@4c0 { 22 spi@4c0 {
18 cell-index = <0>; 23 cell-index = <0>;
@@ -21,4 +26,6 @@ Example:
21 interrupts = <82 0>; 26 interrupts = <82 0>;
22 interrupt-parent = <700>; 27 interrupt-parent = <700>;
23 mode = "cpu"; 28 mode = "cpu";
29 gpios = <&gpio 18 1 // device reg=<0>
30 &gpio 19 1>; // device reg=<1>
24 }; 31 };
diff --git a/Documentation/powerpc/ptrace.txt b/Documentation/powerpc/ptrace.txt
new file mode 100644
index 000000000000..f4a5499b7bc6
--- /dev/null
+++ b/Documentation/powerpc/ptrace.txt
@@ -0,0 +1,134 @@
1GDB intends to support the following hardware debug features of BookE
2processors:
3
44 hardware breakpoints (IAC)
52 hardware watchpoints (read, write and read-write) (DAC)
62 value conditions for the hardware watchpoints (DVC)
7
8For that, we need to extend ptrace so that GDB can query and set these
9resources. Since we're extending, we're trying to create an interface
10that's extendable and that covers both BookE and server processors, so
11that GDB doesn't need to special-case each of them. We added the
12following 3 new ptrace requests.
13
141. PTRACE_PPC_GETHWDEBUGINFO
15
16Query for GDB to discover the hardware debug features. The main info to
17be returned here is the minimum alignment for the hardware watchpoints.
18BookE processors don't have restrictions here, but server processors have
19an 8-byte alignment restriction for hardware watchpoints. We'd like to avoid
20adding special cases to GDB based on what it sees in AUXV.
21
22Since we're at it, we added other useful info that the kernel can return to
23GDB: this query will return the number of hardware breakpoints, hardware
24watchpoints and whether it supports a range of addresses and a condition.
25The query will fill the following structure provided by the requesting process:
26
27struct ppc_debug_info {
28 unit32_t version;
29 unit32_t num_instruction_bps;
30 unit32_t num_data_bps;
31 unit32_t num_condition_regs;
32 unit32_t data_bp_alignment;
33 unit32_t sizeof_condition; /* size of the DVC register */
34 uint64_t features; /* bitmask of the individual flags */
35};
36
37features will have bits indicating whether there is support for:
38
39#define PPC_DEBUG_FEATURE_INSN_BP_RANGE 0x1
40#define PPC_DEBUG_FEATURE_INSN_BP_MASK 0x2
41#define PPC_DEBUG_FEATURE_DATA_BP_RANGE 0x4
42#define PPC_DEBUG_FEATURE_DATA_BP_MASK 0x8
43
442. PTRACE_SETHWDEBUG
45
46Sets a hardware breakpoint or watchpoint, according to the provided structure:
47
48struct ppc_hw_breakpoint {
49 uint32_t version;
50#define PPC_BREAKPOINT_TRIGGER_EXECUTE 0x1
51#define PPC_BREAKPOINT_TRIGGER_READ 0x2
52#define PPC_BREAKPOINT_TRIGGER_WRITE 0x4
53 uint32_t trigger_type; /* only some combinations allowed */
54#define PPC_BREAKPOINT_MODE_EXACT 0x0
55#define PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE 0x1
56#define PPC_BREAKPOINT_MODE_RANGE_EXCLUSIVE 0x2
57#define PPC_BREAKPOINT_MODE_MASK 0x3
58 uint32_t addr_mode; /* address match mode */
59
60#define PPC_BREAKPOINT_CONDITION_MODE 0x3
61#define PPC_BREAKPOINT_CONDITION_NONE 0x0
62#define PPC_BREAKPOINT_CONDITION_AND 0x1
63#define PPC_BREAKPOINT_CONDITION_EXACT 0x1 /* different name for the same thing as above */
64#define PPC_BREAKPOINT_CONDITION_OR 0x2
65#define PPC_BREAKPOINT_CONDITION_AND_OR 0x3
66#define PPC_BREAKPOINT_CONDITION_BE_ALL 0x00ff0000 /* byte enable bits */
67#define PPC_BREAKPOINT_CONDITION_BE(n) (1<<((n)+16))
68 uint32_t condition_mode; /* break/watchpoint condition flags */
69
70 uint64_t addr;
71 uint64_t addr2;
72 uint64_t condition_value;
73};
74
75A request specifies one event, not necessarily just one register to be set.
76For instance, if the request is for a watchpoint with a condition, both the
77DAC and DVC registers will be set in the same request.
78
79With this GDB can ask for all kinds of hardware breakpoints and watchpoints
80that the BookE supports. COMEFROM breakpoints available in server processors
81are not contemplated, but that is out of the scope of this work.
82
83ptrace will return an integer (handle) uniquely identifying the breakpoint or
84watchpoint just created. This integer will be used in the PTRACE_DELHWDEBUG
85request to ask for its removal. Return -ENOSPC if the requested breakpoint
86can't be allocated on the registers.
87
88Some examples of using the structure to:
89
90- set a breakpoint in the first breakpoint register
91
92 p.version = PPC_DEBUG_CURRENT_VERSION;
93 p.trigger_type = PPC_BREAKPOINT_TRIGGER_EXECUTE;
94 p.addr_mode = PPC_BREAKPOINT_MODE_EXACT;
95 p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE;
96 p.addr = (uint64_t) address;
97 p.addr2 = 0;
98 p.condition_value = 0;
99
100- set a watchpoint which triggers on reads in the second watchpoint register
101
102 p.version = PPC_DEBUG_CURRENT_VERSION;
103 p.trigger_type = PPC_BREAKPOINT_TRIGGER_READ;
104 p.addr_mode = PPC_BREAKPOINT_MODE_EXACT;
105 p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE;
106 p.addr = (uint64_t) address;
107 p.addr2 = 0;
108 p.condition_value = 0;
109
110- set a watchpoint which triggers only with a specific value
111
112 p.version = PPC_DEBUG_CURRENT_VERSION;
113 p.trigger_type = PPC_BREAKPOINT_TRIGGER_READ;
114 p.addr_mode = PPC_BREAKPOINT_MODE_EXACT;
115 p.condition_mode = PPC_BREAKPOINT_CONDITION_AND | PPC_BREAKPOINT_CONDITION_BE_ALL;
116 p.addr = (uint64_t) address;
117 p.addr2 = 0;
118 p.condition_value = (uint64_t) condition;
119
120- set a ranged hardware breakpoint
121
122 p.version = PPC_DEBUG_CURRENT_VERSION;
123 p.trigger_type = PPC_BREAKPOINT_TRIGGER_EXECUTE;
124 p.addr_mode = PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE;
125 p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE;
126 p.addr = (uint64_t) begin_range;
127 p.addr2 = (uint64_t) end_range;
128 p.condition_value = 0;
129
1303. PTRACE_DELHWDEBUG
131
132Takes an integer which identifies an existing breakpoint or watchpoint
133(i.e., the value returned from PTRACE_SETHWDEBUG), and deletes the
134corresponding breakpoint or watchpoint..
diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO
index 339207d11d95..d378cba66456 100644
--- a/Documentation/s390/CommonIO
+++ b/Documentation/s390/CommonIO
@@ -87,6 +87,12 @@ Command line parameters
87 compatibility, by the device number in hexadecimal (0xabcd or abcd). Device 87 compatibility, by the device number in hexadecimal (0xabcd or abcd). Device
88 numbers given as 0xabcd will be interpreted as 0.0.abcd. 88 numbers given as 0xabcd will be interpreted as 0.0.abcd.
89 89
90* /proc/cio_settle
91
92 A write request to this file is blocked until all queued cio actions are
93 handled. This will allow userspace to wait for pending work affecting
94 device availability after changing cio_ignore or the hardware configuration.
95
90* For some of the information present in the /proc filesystem in 2.4 (namely, 96* For some of the information present in the /proc filesystem in 2.4 (namely,
91 /proc/subchannels and /proc/chpids), see driver-model.txt. 97 /proc/subchannels and /proc/chpids), see driver-model.txt.
92 Information formerly in /proc/irq_count is now in /proc/interrupts. 98 Information formerly in /proc/irq_count is now in /proc/interrupts.
diff --git a/Documentation/s390/driver-model.txt b/Documentation/s390/driver-model.txt
index bde473df748d..ed265cf54cde 100644
--- a/Documentation/s390/driver-model.txt
+++ b/Documentation/s390/driver-model.txt
@@ -223,8 +223,8 @@ touched by the driver - it should use the ccwgroup device's driver_data for its
223private data. 223private data.
224 224
225To implement a ccwgroup driver, please refer to include/asm/ccwgroup.h. Keep in 225To implement a ccwgroup driver, please refer to include/asm/ccwgroup.h. Keep in
226mind that most drivers will need to implement both a ccwgroup and a ccw driver 226mind that most drivers will need to implement both a ccwgroup and a ccw
227(unless you have a meta ccw driver, like cu3088 for lcs and ctc). 227driver.
228 228
229 229
2302. Channel paths 2302. Channel paths
diff --git a/Documentation/scsi/ChangeLog.megaraid_sas b/Documentation/scsi/ChangeLog.megaraid_sas
index 17ffa0607712..30023568805e 100644
--- a/Documentation/scsi/ChangeLog.megaraid_sas
+++ b/Documentation/scsi/ChangeLog.megaraid_sas
@@ -1,3 +1,19 @@
11 Release Date : Thur. Oct 29, 2009 09:12:45 PST 2009 -
2 (emaild-id:megaraidlinux@lsi.com)
3 Bo Yang
4
52 Current Version : 00.00.04.17.1-rc1
63 Older Version : 00.00.04.12
7
81. Add the pad_0 in mfi frame structure to 0 to fix the
9 context value larger than 32bit value issue.
10
112. Add the logic drive list to the driver. Driver will
12 keep the logic drive list internal after driver load.
13
143. driver fixed the device update issue after get the AEN
15 PD delete/ADD, LD add/delete from FW.
16
11 Release Date : Tues. July 28, 2009 10:12:45 PST 2009 - 171 Release Date : Tues. July 28, 2009 10:12:45 PST 2009 -
2 (emaild-id:megaraidlinux@lsi.com) 18 (emaild-id:megaraidlinux@lsi.com)
3 Bo Yang 19 Bo Yang
diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index 6a5a579126b0..f1f81afee8a0 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -238,11 +238,10 @@ HAVE_SYSCALL_TRACEPOINTS
238 238
239You need very few things to get the syscalls tracing in an arch. 239You need very few things to get the syscalls tracing in an arch.
240 240
241- Support HAVE_ARCH_TRACEHOOK (see arch/Kconfig).
241- Have a NR_syscalls variable in <asm/unistd.h> that provides the number 242- Have a NR_syscalls variable in <asm/unistd.h> that provides the number
242 of syscalls supported by the arch. 243 of syscalls supported by the arch.
243- Implement arch_syscall_addr() that resolves a syscall address from a 244- Support the TIF_SYSCALL_TRACEPOINT thread flags.
244 syscall number.
245- Support the TIF_SYSCALL_TRACEPOINT thread flags
246- Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace 245- Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace
247 in the ptrace syscalls tracing path. 246 in the ptrace syscalls tracing path.
248- Tag this arch as HAVE_SYSCALL_TRACEPOINTS. 247- Tag this arch as HAVE_SYSCALL_TRACEPOINTS.
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 47aabeebbdf6..a9100b28eb84 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -24,6 +24,7 @@ Synopsis of kprobe_events
24------------------------- 24-------------------------
25 p[:[GRP/]EVENT] SYMBOL[+offs]|MEMADDR [FETCHARGS] : Set a probe 25 p[:[GRP/]EVENT] SYMBOL[+offs]|MEMADDR [FETCHARGS] : Set a probe
26 r[:[GRP/]EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe 26 r[:[GRP/]EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe
27 -:[GRP/]EVENT : Clear a probe
27 28
28 GRP : Group name. If omitted, use "kprobes" for it. 29 GRP : Group name. If omitted, use "kprobes" for it.
29 EVENT : Event name. If omitted, the event name is generated 30 EVENT : Event name. If omitted, the event name is generated
@@ -37,15 +38,12 @@ Synopsis of kprobe_events
37 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) 38 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
38 $stackN : Fetch Nth entry of stack (N >= 0) 39 $stackN : Fetch Nth entry of stack (N >= 0)
39 $stack : Fetch stack address. 40 $stack : Fetch stack address.
40 $argN : Fetch function argument. (N >= 0)(*) 41 $retval : Fetch return value.(*)
41 $retval : Fetch return value.(**) 42 +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
42 +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***)
43 NAME=FETCHARG: Set NAME as the argument name of FETCHARG. 43 NAME=FETCHARG: Set NAME as the argument name of FETCHARG.
44 44
45 (*) aN may not correct on asmlinkaged functions and at the middle of 45 (*) only for return probe.
46 function body. 46 (**) this is useful for fetching a field of data structures.
47 (**) only for return probe.
48 (***) this is useful for fetching a field of data structures.
49 47
50 48
51Per-Probe Event Filtering 49Per-Probe Event Filtering
@@ -82,13 +80,16 @@ Usage examples
82To add a probe as a new event, write a new definition to kprobe_events 80To add a probe as a new event, write a new definition to kprobe_events
83as below. 81as below.
84 82
85 echo p:myprobe do_sys_open dfd=$arg0 filename=$arg1 flags=$arg2 mode=$arg3 > /sys/kernel/debug/tracing/kprobe_events 83 echo 'p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack)' > /sys/kernel/debug/tracing/kprobe_events
86 84
87 This sets a kprobe on the top of do_sys_open() function with recording 85 This sets a kprobe on the top of do_sys_open() function with recording
881st to 4th arguments as "myprobe" event. As this example shows, users can 861st to 4th arguments as "myprobe" event. Note, which register/stack entry is
89choose more familiar names for each arguments. 87assigned to each function argument depends on arch-specific ABI. If you unsure
88the ABI, please try to use probe subcommand of perf-tools (you can find it
89under tools/perf/).
90As this example shows, users can choose more familiar names for each arguments.
90 91
91 echo r:myretprobe do_sys_open $retval >> /sys/kernel/debug/tracing/kprobe_events 92 echo 'r:myretprobe do_sys_open $retval' >> /sys/kernel/debug/tracing/kprobe_events
92 93
93 This sets a kretprobe on the return point of do_sys_open() function with 94 This sets a kretprobe on the return point of do_sys_open() function with
94recording return value as "myretprobe" event. 95recording return value as "myretprobe" event.
@@ -97,23 +98,24 @@ recording return value as "myretprobe" event.
97 98
98 cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format 99 cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format
99name: myprobe 100name: myprobe
100ID: 75 101ID: 780
101format: 102format:
102 field:unsigned short common_type; offset:0; size:2; 103 field:unsigned short common_type; offset:0; size:2; signed:0;
103 field:unsigned char common_flags; offset:2; size:1; 104 field:unsigned char common_flags; offset:2; size:1; signed:0;
104 field:unsigned char common_preempt_count; offset:3; size:1; 105 field:unsigned char common_preempt_count; offset:3; size:1;signed:0;
105 field:int common_pid; offset:4; size:4; 106 field:int common_pid; offset:4; size:4; signed:1;
106 field:int common_tgid; offset:8; size:4; 107 field:int common_lock_depth; offset:8; size:4; signed:1;
107 108
108 field: unsigned long ip; offset:16;tsize:8; 109 field:unsigned long __probe_ip; offset:12; size:4; signed:0;
109 field: int nargs; offset:24;tsize:4; 110 field:int __probe_nargs; offset:16; size:4; signed:1;
110 field: unsigned long dfd; offset:32;tsize:8; 111 field:unsigned long dfd; offset:20; size:4; signed:0;
111 field: unsigned long filename; offset:40;tsize:8; 112 field:unsigned long filename; offset:24; size:4; signed:0;
112 field: unsigned long flags; offset:48;tsize:8; 113 field:unsigned long flags; offset:28; size:4; signed:0;
113 field: unsigned long mode; offset:56;tsize:8; 114 field:unsigned long mode; offset:32; size:4; signed:0;
114 115
115print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->ip, REC->dfd, REC->filename, REC->flags, REC->mode
116 116
117print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->__probe_ip,
118REC->dfd, REC->filename, REC->flags, REC->mode
117 119
118 You can see that the event has 4 arguments as in the expressions you specified. 120 You can see that the event has 4 arguments as in the expressions you specified.
119 121
@@ -121,6 +123,12 @@ print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->ip, REC->dfd, R
121 123
122 This clears all probe points. 124 This clears all probe points.
123 125
126 Or,
127
128 echo -:myprobe >> kprobe_events
129
130 This clears probe points selectively.
131
124 Right after definition, each event is disabled by default. For tracing these 132 Right after definition, each event is disabled by default. For tracing these
125events, you need to enable it. 133events, you need to enable it.
126 134
@@ -146,4 +154,3 @@ events, you need to enable it.
146returns from SYMBOL(e.g. "sys_open+0x1b/0x1d <- do_sys_open" means kernel 154returns from SYMBOL(e.g. "sys_open+0x1b/0x1d <- do_sys_open" means kernel
147returns from do_sys_open to sys_open+0x1b). 155returns from do_sys_open to sys_open+0x1b).
148 156
149
diff --git a/Documentation/video4linux/CARDLIST.cx23885 b/Documentation/video4linux/CARDLIST.cx23885
index 7539e8fa1ffd..16ca030e1185 100644
--- a/Documentation/video4linux/CARDLIST.cx23885
+++ b/Documentation/video4linux/CARDLIST.cx23885
@@ -26,3 +26,4 @@
26 25 -> Compro VideoMate E800 [1858:e800] 26 25 -> Compro VideoMate E800 [1858:e800]
27 26 -> Hauppauge WinTV-HVR1290 [0070:8551] 27 26 -> Hauppauge WinTV-HVR1290 [0070:8551]
28 27 -> Mygica X8558 PRO DMB-TH [14f1:8578] 28 27 -> Mygica X8558 PRO DMB-TH [14f1:8578]
29 28 -> LEADTEK WinFast PxTV1200 [107d:6f22]
diff --git a/Documentation/video4linux/CARDLIST.saa7134 b/Documentation/video4linux/CARDLIST.saa7134
index fce1e7eb0474..b4a767060ed7 100644
--- a/Documentation/video4linux/CARDLIST.saa7134
+++ b/Documentation/video4linux/CARDLIST.saa7134
@@ -174,3 +174,4 @@
174173 -> Zolid Hybrid TV Tuner PCI [1131:2004] 174173 -> Zolid Hybrid TV Tuner PCI [1131:2004]
175174 -> Asus Europa Hybrid OEM [1043:4847] 175174 -> Asus Europa Hybrid OEM [1043:4847]
176175 -> Leadtek Winfast DTV1000S [107d:6655] 176175 -> Leadtek Winfast DTV1000S [107d:6655]
177176 -> Beholder BeholdTV 505 RDS [0000:5051]
diff --git a/Documentation/video4linux/CARDLIST.tuner b/Documentation/video4linux/CARDLIST.tuner
index e0d298fe8830..9b2e0dd6017e 100644
--- a/Documentation/video4linux/CARDLIST.tuner
+++ b/Documentation/video4linux/CARDLIST.tuner
@@ -81,3 +81,4 @@ tuner=80 - Philips FQ1216LME MK3 PAL/SECAM w/active loopthrough
81tuner=81 - Partsnic (Daewoo) PTI-5NF05 81tuner=81 - Partsnic (Daewoo) PTI-5NF05
82tuner=82 - Philips CU1216L 82tuner=82 - Philips CU1216L
83tuner=83 - NXP TDA18271 83tuner=83 - NXP TDA18271
84tuner=84 - Sony BTF-Pxn01Z
diff --git a/Documentation/video4linux/README.tlg2300 b/Documentation/video4linux/README.tlg2300
new file mode 100644
index 000000000000..416ccb93d8c9
--- /dev/null
+++ b/Documentation/video4linux/README.tlg2300
@@ -0,0 +1,47 @@
1tlg2300 release notes
2====================
3
4This is a v4l2/dvb device driver for the tlg2300 chip.
5
6
7current status
8==============
9
10video
11 - support mmap and read().(no overlay)
12
13audio
14 - The driver will register a ALSA card for the audio input.
15
16vbi
17 - Works for almost TV norms.
18
19dvb-t
20 - works for DVB-T
21
22FM
23 - Works for radio.
24
25---------------------------------------------------------------------------
26TESTED APPLICATIONS:
27
28-VLC1.0.4 test the video and dvb. The GUI is friendly to use.
29
30-Mplayer test the video.
31
32-Mplayer test the FM. The mplayer should be compiled with --enable-radio and
33 --enable-radio-capture.
34 The command runs as this(The alsa audio registers to card 1):
35 #mplayer radio://103.7/capture/ -radio adevice=hw=1,0:arate=48000 \
36 -rawaudio rate=48000:channels=2
37
38---------------------------------------------------------------------------
39KNOWN PROBLEMS:
40about preemphasis:
41 You can set the preemphasis for radio by the following command:
42 #v4l2-ctl -d /dev/radio0 --set-ctrl=pre_emphasis_settings=1
43
44 "pre_emphasis_settings=1" means that you select the 50us. If you want
45 to select the 75us, please use "pre_emphasis_settings=2"
46
47
diff --git a/Documentation/video4linux/gspca.txt b/Documentation/video4linux/gspca.txt
index 1800a62cf135..181b9e6fd984 100644
--- a/Documentation/video4linux/gspca.txt
+++ b/Documentation/video4linux/gspca.txt
@@ -42,6 +42,7 @@ ov519 041e:4064 Creative Live! VISTA VF0420
42ov519 041e:4067 Creative Live! Cam Video IM (VF0350) 42ov519 041e:4067 Creative Live! Cam Video IM (VF0350)
43ov519 041e:4068 Creative Live! VISTA VF0470 43ov519 041e:4068 Creative Live! VISTA VF0470
44spca561 0458:7004 Genius VideoCAM Express V2 44spca561 0458:7004 Genius VideoCAM Express V2
45sn9c2028 0458:7005 Genius Smart 300, version 2
45sunplus 0458:7006 Genius Dsc 1.3 Smart 46sunplus 0458:7006 Genius Dsc 1.3 Smart
46zc3xx 0458:7007 Genius VideoCam V2 47zc3xx 0458:7007 Genius VideoCam V2
47zc3xx 0458:700c Genius VideoCam V3 48zc3xx 0458:700c Genius VideoCam V3
@@ -109,6 +110,7 @@ sunplus 04a5:3003 Benq DC 1300
109sunplus 04a5:3008 Benq DC 1500 110sunplus 04a5:3008 Benq DC 1500
110sunplus 04a5:300a Benq DC 3410 111sunplus 04a5:300a Benq DC 3410
111spca500 04a5:300c Benq DC 1016 112spca500 04a5:300c Benq DC 1016
113benq 04a5:3035 Benq DC E300
112finepix 04cb:0104 Fujifilm FinePix 4800 114finepix 04cb:0104 Fujifilm FinePix 4800
113finepix 04cb:0109 Fujifilm FinePix A202 115finepix 04cb:0109 Fujifilm FinePix A202
114finepix 04cb:010b Fujifilm FinePix A203 116finepix 04cb:010b Fujifilm FinePix A203
@@ -142,6 +144,7 @@ sunplus 04fc:5360 Sunplus Generic
142spca500 04fc:7333 PalmPixDC85 144spca500 04fc:7333 PalmPixDC85
143sunplus 04fc:ffff Pure DigitalDakota 145sunplus 04fc:ffff Pure DigitalDakota
144spca501 0506:00df 3Com HomeConnect Lite 146spca501 0506:00df 3Com HomeConnect Lite
147sunplus 052b:1507 Megapixel 5 Pretec DC-1007
145sunplus 052b:1513 Megapix V4 148sunplus 052b:1513 Megapix V4
146sunplus 052b:1803 MegaImage VI 149sunplus 052b:1803 MegaImage VI
147tv8532 0545:808b Veo Stingray 150tv8532 0545:808b Veo Stingray
@@ -151,6 +154,7 @@ sunplus 0546:3191 Polaroid Ion 80
151sunplus 0546:3273 Polaroid PDC2030 154sunplus 0546:3273 Polaroid PDC2030
152ov519 054c:0154 Sonny toy4 155ov519 054c:0154 Sonny toy4
153ov519 054c:0155 Sonny toy5 156ov519 054c:0155 Sonny toy5
157cpia1 0553:0002 CPIA CPiA (version1) based cameras
154zc3xx 055f:c005 Mustek Wcam300A 158zc3xx 055f:c005 Mustek Wcam300A
155spca500 055f:c200 Mustek Gsmart 300 159spca500 055f:c200 Mustek Gsmart 300
156sunplus 055f:c211 Kowa Bs888e Microcamera 160sunplus 055f:c211 Kowa Bs888e Microcamera
@@ -188,8 +192,7 @@ spca500 06bd:0404 Agfa CL20
188spca500 06be:0800 Optimedia 192spca500 06be:0800 Optimedia
189sunplus 06d6:0031 Trust 610 LCD PowerC@m Zoom 193sunplus 06d6:0031 Trust 610 LCD PowerC@m Zoom
190spca506 06e1:a190 ADS Instant VCD 194spca506 06e1:a190 ADS Instant VCD
191ov534 06f8:3002 Hercules Blog Webcam 195ov534_9 06f8:3003 Hercules Dualpix HD Weblog
192ov534 06f8:3003 Hercules Dualpix HD Weblog
193sonixj 06f8:3004 Hercules Classic Silver 196sonixj 06f8:3004 Hercules Classic Silver
194sonixj 06f8:3008 Hercules Deluxe Optical Glass 197sonixj 06f8:3008 Hercules Deluxe Optical Glass
195pac7302 06f8:3009 Hercules Classic Link 198pac7302 06f8:3009 Hercules Classic Link
@@ -204,6 +207,7 @@ sunplus 0733:2221 Mercury Digital Pro 3.1p
204sunplus 0733:3261 Concord 3045 spca536a 207sunplus 0733:3261 Concord 3045 spca536a
205sunplus 0733:3281 Cyberpix S550V 208sunplus 0733:3281 Cyberpix S550V
206spca506 0734:043b 3DeMon USB Capture aka 209spca506 0734:043b 3DeMon USB Capture aka
210cpia1 0813:0001 QX3 camera
207ov519 0813:0002 Dual Mode USB Camera Plus 211ov519 0813:0002 Dual Mode USB Camera Plus
208spca500 084d:0003 D-Link DSC-350 212spca500 084d:0003 D-Link DSC-350
209spca500 08ca:0103 Aiptek PocketDV 213spca500 08ca:0103 Aiptek PocketDV
@@ -225,7 +229,8 @@ sunplus 08ca:2050 Medion MD 41437
225sunplus 08ca:2060 Aiptek PocketDV5300 229sunplus 08ca:2060 Aiptek PocketDV5300
226tv8532 0923:010f ICM532 cams 230tv8532 0923:010f ICM532 cams
227mars 093a:050f Mars-Semi Pc-Camera 231mars 093a:050f Mars-Semi Pc-Camera
228mr97310a 093a:010f Sakar Digital no. 77379 232mr97310a 093a:010e All known CIF cams with this ID
233mr97310a 093a:010f All known VGA cams with this ID
229pac207 093a:2460 Qtec Webcam 100 234pac207 093a:2460 Qtec Webcam 100
230pac207 093a:2461 HP Webcam 235pac207 093a:2461 HP Webcam
231pac207 093a:2463 Philips SPC 220 NC 236pac207 093a:2463 Philips SPC 220 NC
@@ -302,6 +307,7 @@ sonixj 0c45:613b Surfer SN-206
302sonixj 0c45:613c Sonix Pccam168 307sonixj 0c45:613c Sonix Pccam168
303sonixj 0c45:6143 Sonix Pccam168 308sonixj 0c45:6143 Sonix Pccam168
304sonixj 0c45:6148 Digitus DA-70811/ZSMC USB PC Camera ZS211/Microdia 309sonixj 0c45:6148 Digitus DA-70811/ZSMC USB PC Camera ZS211/Microdia
310sonixj 0c45:614a Frontech E-Ccam (JIL-2225)
305sn9c20x 0c45:6240 PC Camera (SN9C201 + MT9M001) 311sn9c20x 0c45:6240 PC Camera (SN9C201 + MT9M001)
306sn9c20x 0c45:6242 PC Camera (SN9C201 + MT9M111) 312sn9c20x 0c45:6242 PC Camera (SN9C201 + MT9M111)
307sn9c20x 0c45:6248 PC Camera (SN9C201 + OV9655) 313sn9c20x 0c45:6248 PC Camera (SN9C201 + OV9655)
@@ -324,6 +330,10 @@ sn9c20x 0c45:62b0 PC Camera (SN9C202 + MT9V011/MT9V111/MT9V112)
324sn9c20x 0c45:62b3 PC Camera (SN9C202 + OV9655) 330sn9c20x 0c45:62b3 PC Camera (SN9C202 + OV9655)
325sn9c20x 0c45:62bb PC Camera (SN9C202 + OV7660) 331sn9c20x 0c45:62bb PC Camera (SN9C202 + OV7660)
326sn9c20x 0c45:62bc PC Camera (SN9C202 + HV7131R) 332sn9c20x 0c45:62bc PC Camera (SN9C202 + HV7131R)
333sn9c2028 0c45:8001 Wild Planet Digital Spy Camera
334sn9c2028 0c45:8003 Sakar #11199, #6637x, #67480 keychain cams
335sn9c2028 0c45:8008 Mini-Shotz ms-350
336sn9c2028 0c45:800a Vivitar Vivicam 3350B
327sunplus 0d64:0303 Sunplus FashionCam DXG 337sunplus 0d64:0303 Sunplus FashionCam DXG
328ov519 0e96:c001 TRUST 380 USB2 SPACEC@M 338ov519 0e96:c001 TRUST 380 USB2 SPACEC@M
329etoms 102c:6151 Qcam Sangha CIF 339etoms 102c:6151 Qcam Sangha CIF
@@ -341,10 +351,11 @@ spca501 1776:501c Arowana 300K CMOS Camera
341t613 17a1:0128 TASCORP JPEG Webcam, NGS Cyclops 351t613 17a1:0128 TASCORP JPEG Webcam, NGS Cyclops
342vc032x 17ef:4802 Lenovo Vc0323+MI1310_SOC 352vc032x 17ef:4802 Lenovo Vc0323+MI1310_SOC
343pac207 2001:f115 D-Link DSB-C120 353pac207 2001:f115 D-Link DSB-C120
344sq905c 2770:9050 sq905c 354sq905c 2770:9050 Disney pix micro (CIF)
345sq905c 2770:905c DualCamera 355sq905c 2770:9052 Disney pix micro 2 (VGA)
346sq905 2770:9120 Argus Digital Camera DC1512 356sq905c 2770:905c All 11 known cameras with this ID
347sq905c 2770:913d sq905c 357sq905 2770:9120 All 24 known cameras with this ID
358sq905c 2770:913d All 4 known cameras with this ID
348spca500 2899:012c Toptro Industrial 359spca500 2899:012c Toptro Industrial
349ov519 8020:ef04 ov519 360ov519 8020:ef04 ov519
350spca508 8086:0110 Intel Easy PC Camera 361spca508 8086:0110 Intel Easy PC Camera
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 74d677c8b036..5155700c206b 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -599,99 +599,13 @@ video_device::minor fields.
599video buffer helper functions 599video buffer helper functions
600----------------------------- 600-----------------------------
601 601
602The v4l2 core API provides a standard method for dealing with video 602The v4l2 core API provides a set of standard methods (called "videobuf")
603buffers. Those methods allow a driver to implement read(), mmap() and 603for dealing with video buffers. Those methods allow a driver to implement
604overlay() on a consistent way. 604read(), mmap() and overlay() in a consistent way. There are currently
605 605methods for using video buffers on devices that supports DMA with
606There are currently methods for using video buffers on devices that 606scatter/gather method (videobuf-dma-sg), DMA with linear access
607supports DMA with scatter/gather method (videobuf-dma-sg), DMA with 607(videobuf-dma-contig), and vmalloced buffers, mostly used on USB drivers
608linear access (videobuf-dma-contig), and vmalloced buffers, mostly 608(videobuf-vmalloc).
609used on USB drivers (videobuf-vmalloc). 609
610 610Please see Documentation/video4linux/videobuf for more information on how
611Any driver using videobuf should provide operations (callbacks) for 611to use the videobuf layer.
612four handlers:
613
614ops->buf_setup - calculates the size of the video buffers and avoid they
615 to waste more than some maximum limit of RAM;
616ops->buf_prepare - fills the video buffer structs and calls
617 videobuf_iolock() to alloc and prepare mmaped memory;
618ops->buf_queue - advices the driver that another buffer were
619 requested (by read() or by QBUF);
620ops->buf_release - frees any buffer that were allocated.
621
622In order to use it, the driver need to have a code (generally called at
623interrupt context) that will properly handle the buffer request lists,
624announcing that a new buffer were filled.
625
626The irq handling code should handle the videobuf task lists, in order
627to advice videobuf that a new frame were filled, in order to honor to a
628request. The code is generally like this one:
629 if (list_empty(&dma_q->active))
630 return;
631
632 buf = list_entry(dma_q->active.next, struct vbuffer, vb.queue);
633
634 if (!waitqueue_active(&buf->vb.done))
635 return;
636
637 /* Some logic to handle the buf may be needed here */
638
639 list_del(&buf->vb.queue);
640 do_gettimeofday(&buf->vb.ts);
641 wake_up(&buf->vb.done);
642
643Those are the videobuffer functions used on drivers, implemented on
644videobuf-core:
645
646- Videobuf init functions
647 videobuf_queue_sg_init()
648 Initializes the videobuf infrastructure. This function should be
649 called before any other videobuf function on drivers that uses DMA
650 Scatter/Gather buffers.
651
652 videobuf_queue_dma_contig_init
653 Initializes the videobuf infrastructure. This function should be
654 called before any other videobuf function on drivers that need DMA
655 contiguous buffers.
656
657 videobuf_queue_vmalloc_init()
658 Initializes the videobuf infrastructure. This function should be
659 called before any other videobuf function on USB (and other drivers)
660 that need a vmalloced type of videobuf.
661
662- videobuf_iolock()
663 Prepares the videobuf memory for the proper method (read, mmap, overlay).
664
665- videobuf_queue_is_busy()
666 Checks if a videobuf is streaming.
667
668- videobuf_queue_cancel()
669 Stops video handling.
670
671- videobuf_mmap_free()
672 frees mmap buffers.
673
674- videobuf_stop()
675 Stops video handling, ends mmap and frees mmap and other buffers.
676
677- V4L2 api functions. Those functions correspond to VIDIOC_foo ioctls:
678 videobuf_reqbufs(), videobuf_querybuf(), videobuf_qbuf(),
679 videobuf_dqbuf(), videobuf_streamon(), videobuf_streamoff().
680
681- V4L1 api function (corresponds to VIDIOCMBUF ioctl):
682 videobuf_cgmbuf()
683 This function is used to provide backward compatibility with V4L1
684 API.
685
686- Some help functions for read()/poll() operations:
687 videobuf_read_stream()
688 For continuous stream read()
689 videobuf_read_one()
690 For snapshot read()
691 videobuf_poll_stream()
692 polling help function
693
694The better way to understand it is to take a look at vivi driver. One
695of the main reasons for vivi is to be a videobuf usage example. the
696vivi_thread_tick() does the task that the IRQ callback would do on PCI
697drivers (or the irq callback on USB).
diff --git a/Documentation/video4linux/videobuf b/Documentation/video4linux/videobuf
new file mode 100644
index 000000000000..17a1f9abf260
--- /dev/null
+++ b/Documentation/video4linux/videobuf
@@ -0,0 +1,360 @@
1An introduction to the videobuf layer
2Jonathan Corbet <corbet@lwn.net>
3Current as of 2.6.33
4
5The videobuf layer functions as a sort of glue layer between a V4L2 driver
6and user space. It handles the allocation and management of buffers for
7the storage of video frames. There is a set of functions which can be used
8to implement many of the standard POSIX I/O system calls, including read(),
9poll(), and, happily, mmap(). Another set of functions can be used to
10implement the bulk of the V4L2 ioctl() calls related to streaming I/O,
11including buffer allocation, queueing and dequeueing, and streaming
12control. Using videobuf imposes a few design decisions on the driver
13author, but the payback comes in the form of reduced code in the driver and
14a consistent implementation of the V4L2 user-space API.
15
16Buffer types
17
18Not all video devices use the same kind of buffers. In fact, there are (at
19least) three common variations:
20
21 - Buffers which are scattered in both the physical and (kernel) virtual
22 address spaces. (Almost) all user-space buffers are like this, but it
23 makes great sense to allocate kernel-space buffers this way as well when
24 it is possible. Unfortunately, it is not always possible; working with
25 this kind of buffer normally requires hardware which can do
26 scatter/gather DMA operations.
27
28 - Buffers which are physically scattered, but which are virtually
29 contiguous; buffers allocated with vmalloc(), in other words. These
30 buffers are just as hard to use for DMA operations, but they can be
31 useful in situations where DMA is not available but virtually-contiguous
32 buffers are convenient.
33
34 - Buffers which are physically contiguous. Allocation of this kind of
35 buffer can be unreliable on fragmented systems, but simpler DMA
36 controllers cannot deal with anything else.
37
38Videobuf can work with all three types of buffers, but the driver author
39must pick one at the outset and design the driver around that decision.
40
41[It's worth noting that there's a fourth kind of buffer: "overlay" buffers
42which are located within the system's video memory. The overlay
43functionality is considered to be deprecated for most use, but it still
44shows up occasionally in system-on-chip drivers where the performance
45benefits merit the use of this technique. Overlay buffers can be handled
46as a form of scattered buffer, but there are very few implementations in
47the kernel and a description of this technique is currently beyond the
48scope of this document.]
49
50Data structures, callbacks, and initialization
51
52Depending on which type of buffers are being used, the driver should
53include one of the following files:
54
55 <media/videobuf-dma-sg.h> /* Physically scattered */
56 <media/videobuf-vmalloc.h> /* vmalloc() buffers */
57 <media/videobuf-dma-contig.h> /* Physically contiguous */
58
59The driver's data structure describing a V4L2 device should include a
60struct videobuf_queue instance for the management of the buffer queue,
61along with a list_head for the queue of available buffers. There will also
62need to be an interrupt-safe spinlock which is used to protect (at least)
63the queue.
64
65The next step is to write four simple callbacks to help videobuf deal with
66the management of buffers:
67
68 struct videobuf_queue_ops {
69 int (*buf_setup)(struct videobuf_queue *q,
70 unsigned int *count, unsigned int *size);
71 int (*buf_prepare)(struct videobuf_queue *q,
72 struct videobuf_buffer *vb,
73 enum v4l2_field field);
74 void (*buf_queue)(struct videobuf_queue *q,
75 struct videobuf_buffer *vb);
76 void (*buf_release)(struct videobuf_queue *q,
77 struct videobuf_buffer *vb);
78 };
79
80buf_setup() is called early in the I/O process, when streaming is being
81initiated; its purpose is to tell videobuf about the I/O stream. The count
82parameter will be a suggested number of buffers to use; the driver should
83check it for rationality and adjust it if need be. As a practical rule, a
84minimum of two buffers are needed for proper streaming, and there is
85usually a maximum (which cannot exceed 32) which makes sense for each
86device. The size parameter should be set to the expected (maximum) size
87for each frame of data.
88
89Each buffer (in the form of a struct videobuf_buffer pointer) will be
90passed to buf_prepare(), which should set the buffer's size, width, height,
91and field fields properly. If the buffer's state field is
92VIDEOBUF_NEEDS_INIT, the driver should pass it to:
93
94 int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
95 struct v4l2_framebuffer *fbuf);
96
97Among other things, this call will usually allocate memory for the buffer.
98Finally, the buf_prepare() function should set the buffer's state to
99VIDEOBUF_PREPARED.
100
101When a buffer is queued for I/O, it is passed to buf_queue(), which should
102put it onto the driver's list of available buffers and set its state to
103VIDEOBUF_QUEUED. Note that this function is called with the queue spinlock
104held; if it tries to acquire it as well things will come to a screeching
105halt. Yes, this is the voice of experience. Note also that videobuf may
106wait on the first buffer in the queue; placing other buffers in front of it
107could again gum up the works. So use list_add_tail() to enqueue buffers.
108
109Finally, buf_release() is called when a buffer is no longer intended to be
110used. The driver should ensure that there is no I/O active on the buffer,
111then pass it to the appropriate free routine(s):
112
113 /* Scatter/gather drivers */
114 int videobuf_dma_unmap(struct videobuf_queue *q,
115 struct videobuf_dmabuf *dma);
116 int videobuf_dma_free(struct videobuf_dmabuf *dma);
117
118 /* vmalloc drivers */
119 void videobuf_vmalloc_free (struct videobuf_buffer *buf);
120
121 /* Contiguous drivers */
122 void videobuf_dma_contig_free(struct videobuf_queue *q,
123 struct videobuf_buffer *buf);
124
125One way to ensure that a buffer is no longer under I/O is to pass it to:
126
127 int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
128
129Here, vb is the buffer, non_blocking indicates whether non-blocking I/O
130should be used (it should be zero in the buf_release() case), and intr
131controls whether an interruptible wait is used.
132
133File operations
134
135At this point, much of the work is done; much of the rest is slipping
136videobuf calls into the implementation of the other driver callbacks. The
137first step is in the open() function, which must initialize the
138videobuf queue. The function to use depends on the type of buffer used:
139
140 void videobuf_queue_sg_init(struct videobuf_queue *q,
141 struct videobuf_queue_ops *ops,
142 struct device *dev,
143 spinlock_t *irqlock,
144 enum v4l2_buf_type type,
145 enum v4l2_field field,
146 unsigned int msize,
147 void *priv);
148
149 void videobuf_queue_vmalloc_init(struct videobuf_queue *q,
150 struct videobuf_queue_ops *ops,
151 struct device *dev,
152 spinlock_t *irqlock,
153 enum v4l2_buf_type type,
154 enum v4l2_field field,
155 unsigned int msize,
156 void *priv);
157
158 void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
159 struct videobuf_queue_ops *ops,
160 struct device *dev,
161 spinlock_t *irqlock,
162 enum v4l2_buf_type type,
163 enum v4l2_field field,
164 unsigned int msize,
165 void *priv);
166
167In each case, the parameters are the same: q is the queue structure for the
168device, ops is the set of callbacks as described above, dev is the device
169structure for this video device, irqlock is an interrupt-safe spinlock to
170protect access to the data structures, type is the buffer type used by the
171device (cameras will use V4L2_BUF_TYPE_VIDEO_CAPTURE, for example), field
172describes which field is being captured (often V4L2_FIELD_NONE for
173progressive devices), msize is the size of any containing structure used
174around struct videobuf_buffer, and priv is a private data pointer which
175shows up in the priv_data field of struct videobuf_queue. Note that these
176are void functions which, evidently, are immune to failure.
177
178V4L2 capture drivers can be written to support either of two APIs: the
179read() system call and the rather more complicated streaming mechanism. As
180a general rule, it is necessary to support both to ensure that all
181applications have a chance of working with the device. Videobuf makes it
182easy to do that with the same code. To implement read(), the driver need
183only make a call to one of:
184
185 ssize_t videobuf_read_one(struct videobuf_queue *q,
186 char __user *data, size_t count,
187 loff_t *ppos, int nonblocking);
188
189 ssize_t videobuf_read_stream(struct videobuf_queue *q,
190 char __user *data, size_t count,
191 loff_t *ppos, int vbihack, int nonblocking);
192
193Either one of these functions will read frame data into data, returning the
194amount actually read; the difference is that videobuf_read_one() will only
195read a single frame, while videobuf_read_stream() will read multiple frames
196if they are needed to satisfy the count requested by the application. A
197typical driver read() implementation will start the capture engine, call
198one of the above functions, then stop the engine before returning (though a
199smarter implementation might leave the engine running for a little while in
200anticipation of another read() call happening in the near future).
201
202The poll() function can usually be implemented with a direct call to:
203
204 unsigned int videobuf_poll_stream(struct file *file,
205 struct videobuf_queue *q,
206 poll_table *wait);
207
208Note that the actual wait queue eventually used will be the one associated
209with the first available buffer.
210
211When streaming I/O is done to kernel-space buffers, the driver must support
212the mmap() system call to enable user space to access the data. In many
213V4L2 drivers, the often-complex mmap() implementation simplifies to a
214single call to:
215
216 int videobuf_mmap_mapper(struct videobuf_queue *q,
217 struct vm_area_struct *vma);
218
219Everything else is handled by the videobuf code.
220
221The release() function requires two separate videobuf calls:
222
223 void videobuf_stop(struct videobuf_queue *q);
224 int videobuf_mmap_free(struct videobuf_queue *q);
225
226The call to videobuf_stop() terminates any I/O in progress - though it is
227still up to the driver to stop the capture engine. The call to
228videobuf_mmap_free() will ensure that all buffers have been unmapped; if
229so, they will all be passed to the buf_release() callback. If buffers
230remain mapped, videobuf_mmap_free() returns an error code instead. The
231purpose is clearly to cause the closing of the file descriptor to fail if
232buffers are still mapped, but every driver in the 2.6.32 kernel cheerfully
233ignores its return value.
234
235ioctl() operations
236
237The V4L2 API includes a very long list of driver callbacks to respond to
238the many ioctl() commands made available to user space. A number of these
239- those associated with streaming I/O - turn almost directly into videobuf
240calls. The relevant helper functions are:
241
242 int videobuf_reqbufs(struct videobuf_queue *q,
243 struct v4l2_requestbuffers *req);
244 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
245 int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b);
246 int videobuf_dqbuf(struct videobuf_queue *q, struct v4l2_buffer *b,
247 int nonblocking);
248 int videobuf_streamon(struct videobuf_queue *q);
249 int videobuf_streamoff(struct videobuf_queue *q);
250 int videobuf_cgmbuf(struct videobuf_queue *q, struct video_mbuf *mbuf,
251 int count);
252
253So, for example, a VIDIOC_REQBUFS call turns into a call to the driver's
254vidioc_reqbufs() callback which, in turn, usually only needs to locate the
255proper struct videobuf_queue pointer and pass it to videobuf_reqbufs().
256These support functions can replace a great deal of buffer management
257boilerplate in a lot of V4L2 drivers.
258
259The vidioc_streamon() and vidioc_streamoff() functions will be a bit more
260complex, of course, since they will also need to deal with starting and
261stopping the capture engine. videobuf_cgmbuf(), called from the driver's
262vidiocgmbuf() function, only exists if the V4L1 compatibility module has
263been selected with CONFIG_VIDEO_V4L1_COMPAT, so its use must be surrounded
264with #ifdef directives.
265
266Buffer allocation
267
268Thus far, we have talked about buffers, but have not looked at how they are
269allocated. The scatter/gather case is the most complex on this front. For
270allocation, the driver can leave buffer allocation entirely up to the
271videobuf layer; in this case, buffers will be allocated as anonymous
272user-space pages and will be very scattered indeed. If the application is
273using user-space buffers, no allocation is needed; the videobuf layer will
274take care of calling get_user_pages() and filling in the scatterlist array.
275
276If the driver needs to do its own memory allocation, it should be done in
277the vidioc_reqbufs() function, *after* calling videobuf_reqbufs(). The
278first step is a call to:
279
280 struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf);
281
282The returned videobuf_dmabuf structure (defined in
283<media/videobuf-dma-sg.h>) includes a couple of relevant fields:
284
285 struct scatterlist *sglist;
286 int sglen;
287
288The driver must allocate an appropriately-sized scatterlist array and
289populate it with pointers to the pieces of the allocated buffer; sglen
290should be set to the length of the array.
291
292Drivers using the vmalloc() method need not (and cannot) concern themselves
293with buffer allocation at all; videobuf will handle those details. The
294same is normally true of contiguous-DMA drivers as well; videobuf will
295allocate the buffers (with dma_alloc_coherent()) when it sees fit. That
296means that these drivers may be trying to do high-order allocations at any
297time, an operation which is not always guaranteed to work. Some drivers
298play tricks by allocating DMA space at system boot time; videobuf does not
299currently play well with those drivers.
300
301As of 2.6.31, contiguous-DMA drivers can work with a user-supplied buffer,
302as long as that buffer is physically contiguous. Normal user-space
303allocations will not meet that criterion, but buffers obtained from other
304kernel drivers, or those contained within huge pages, will work with these
305drivers.
306
307Filling the buffers
308
309The final part of a videobuf implementation has no direct callback - it's
310the portion of the code which actually puts frame data into the buffers,
311usually in response to interrupts from the device. For all types of
312drivers, this process works approximately as follows:
313
314 - Obtain the next available buffer and make sure that somebody is actually
315 waiting for it.
316
317 - Get a pointer to the memory and put video data there.
318
319 - Mark the buffer as done and wake up the process waiting for it.
320
321Step (1) above is done by looking at the driver-managed list_head structure
322- the one which is filled in the buf_queue() callback. Because starting
323the engine and enqueueing buffers are done in separate steps, it's possible
324for the engine to be running without any buffers available - in the
325vmalloc() case especially. So the driver should be prepared for the list
326to be empty. It is equally possible that nobody is yet interested in the
327buffer; the driver should not remove it from the list or fill it until a
328process is waiting on it. That test can be done by examining the buffer's
329done field (a wait_queue_head_t structure) with waitqueue_active().
330
331A buffer's state should be set to VIDEOBUF_ACTIVE before being mapped for
332DMA; that ensures that the videobuf layer will not try to do anything with
333it while the device is transferring data.
334
335For scatter/gather drivers, the needed memory pointers will be found in the
336scatterlist structure described above. Drivers using the vmalloc() method
337can get a memory pointer with:
338
339 void *videobuf_to_vmalloc(struct videobuf_buffer *buf);
340
341For contiguous DMA drivers, the function to use is:
342
343 dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf);
344
345The contiguous DMA API goes out of its way to hide the kernel-space address
346of the DMA buffer from drivers.
347
348The final step is to set the size field of the relevant videobuf_buffer
349structure to the actual size of the captured image, set state to
350VIDEOBUF_DONE, then call wake_up() on the done queue. At this point, the
351buffer is owned by the videobuf layer and the driver should not touch it
352again.
353
354Developers who are interested in more information can go into the relevant
355header files; there are a few low-level functions declared there which have
356not been talked about here. Also worthwhile is the vivi driver
357(drivers/media/video/vivi.c), which is maintained as an example of how V4L2
358drivers should be written. Vivi only uses the vmalloc() API, but it's good
359enough to get started with. Note also that all of these calls are exported
360GPL-only, so they will not be available to non-GPL kernel modules.
diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 29a6ff8bc7d3..7fbbaf85f5b7 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -166,19 +166,13 @@ NUMA
166 166
167 numa=noacpi Don't parse the SRAT table for NUMA setup 167 numa=noacpi Don't parse the SRAT table for NUMA setup
168 168
169 numa=fake=CMDLINE 169 numa=fake=<size>[MG]
170 If a number, fakes CMDLINE nodes and ignores NUMA setup of the 170 If given as a memory unit, fills all system RAM with nodes of
171 actual machine. Otherwise, system memory is configured 171 size interleaved over physical nodes.
172 depending on the sizes and coefficients listed. For example: 172
173 numa=fake=2*512,1024,4*256,*128 173 numa=fake=<N>
174 gives two 512M nodes, a 1024M node, four 256M nodes, and the 174 If given as an integer, fills all system RAM with N fake nodes
175 rest split into 128M chunks. If the last character of CMDLINE 175 interleaved over physical nodes.
176 is a *, the remaining memory is divided up equally among its
177 coefficient:
178 numa=fake=2*512,2*
179 gives two 512M nodes and the rest split into two nodes.
180 Otherwise, the remaining system RAM is allocated to an
181 additional node.
182 176
183ACPI 177ACPI
184 178