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-rw-r--r--Documentation/ABI/testing/sysfs-block34
-rw-r--r--Documentation/ABI/testing/sysfs-bus-css35
-rw-r--r--Documentation/block/data-integrity.txt327
-rw-r--r--Documentation/ioctl-number.txt1
-rw-r--r--Documentation/sound/alsa/ALSA-Configuration.txt17
-rw-r--r--Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl4
6 files changed, 413 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index 4bd9ea539129..44f52a4f5903 100644
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -26,3 +26,37 @@ Description:
26 I/O statistics of partition <part>. The format is the 26 I/O statistics of partition <part>. The format is the
27 same as the above-written /sys/block/<disk>/stat 27 same as the above-written /sys/block/<disk>/stat
28 format. 28 format.
29
30
31What: /sys/block/<disk>/integrity/format
32Date: June 2008
33Contact: Martin K. Petersen <martin.petersen@oracle.com>
34Description:
35 Metadata format for integrity capable block device.
36 E.g. T10-DIF-TYPE1-CRC.
37
38
39What: /sys/block/<disk>/integrity/read_verify
40Date: June 2008
41Contact: Martin K. Petersen <martin.petersen@oracle.com>
42Description:
43 Indicates whether the block layer should verify the
44 integrity of read requests serviced by devices that
45 support sending integrity metadata.
46
47
48What: /sys/block/<disk>/integrity/tag_size
49Date: June 2008
50Contact: Martin K. Petersen <martin.petersen@oracle.com>
51Description:
52 Number of bytes of integrity tag space available per
53 512 bytes of data.
54
55
56What: /sys/block/<disk>/integrity/write_generate
57Date: June 2008
58Contact: Martin K. Petersen <martin.petersen@oracle.com>
59Description:
60 Indicates whether the block layer should automatically
61 generate checksums for write requests bound for
62 devices that support receiving integrity metadata.
diff --git a/Documentation/ABI/testing/sysfs-bus-css b/Documentation/ABI/testing/sysfs-bus-css
new file mode 100644
index 000000000000..b585ec258a08
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-css
@@ -0,0 +1,35 @@
1What: /sys/bus/css/devices/.../type
2Date: March 2008
3Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
4 linux-s390@vger.kernel.org
5Description: Contains the subchannel type, as reported by the hardware.
6 This attribute is present for all subchannel types.
7
8What: /sys/bus/css/devices/.../modalias
9Date: March 2008
10Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
11 linux-s390@vger.kernel.org
12Description: Contains the module alias as reported with uevents.
13 It is of the format css:t<type> and present for all
14 subchannel types.
15
16What: /sys/bus/css/drivers/io_subchannel/.../chpids
17Date: December 2002
18Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
19 linux-s390@vger.kernel.org
20Description: Contains the ids of the channel paths used by this
21 subchannel, as reported by the channel subsystem
22 during subchannel recognition.
23 Note: This is an I/O-subchannel specific attribute.
24Users: s390-tools, HAL
25
26What: /sys/bus/css/drivers/io_subchannel/.../pimpampom
27Date: December 2002
28Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
29 linux-s390@vger.kernel.org
30Description: Contains the PIM/PAM/POM values, as reported by the
31 channel subsystem when last queried by the common I/O
32 layer (this implies that this attribute is not neccessarily
33 in sync with the values current in the channel subsystem).
34 Note: This is an I/O-subchannel specific attribute.
35Users: s390-tools, HAL
diff --git a/Documentation/block/data-integrity.txt b/Documentation/block/data-integrity.txt
new file mode 100644
index 000000000000..e9dc8d86adc7
--- /dev/null
+++ b/Documentation/block/data-integrity.txt
@@ -0,0 +1,327 @@
1----------------------------------------------------------------------
21. INTRODUCTION
3
4Modern filesystems feature checksumming of data and metadata to
5protect against data corruption. However, the detection of the
6corruption is done at read time which could potentially be months
7after the data was written. At that point the original data that the
8application tried to write is most likely lost.
9
10The solution is to ensure that the disk is actually storing what the
11application meant it to. Recent additions to both the SCSI family
12protocols (SBC Data Integrity Field, SCC protection proposal) as well
13as SATA/T13 (External Path Protection) try to remedy this by adding
14support for appending integrity metadata to an I/O. The integrity
15metadata (or protection information in SCSI terminology) includes a
16checksum for each sector as well as an incrementing counter that
17ensures the individual sectors are written in the right order. And
18for some protection schemes also that the I/O is written to the right
19place on disk.
20
21Current storage controllers and devices implement various protective
22measures, for instance checksumming and scrubbing. But these
23technologies are working in their own isolated domains or at best
24between adjacent nodes in the I/O path. The interesting thing about
25DIF and the other integrity extensions is that the protection format
26is well defined and every node in the I/O path can verify the
27integrity of the I/O and reject it if corruption is detected. This
28allows not only corruption prevention but also isolation of the point
29of failure.
30
31----------------------------------------------------------------------
322. THE DATA INTEGRITY EXTENSIONS
33
34As written, the protocol extensions only protect the path between
35controller and storage device. However, many controllers actually
36allow the operating system to interact with the integrity metadata
37(IMD). We have been working with several FC/SAS HBA vendors to enable
38the protection information to be transferred to and from their
39controllers.
40
41The SCSI Data Integrity Field works by appending 8 bytes of protection
42information to each sector. The data + integrity metadata is stored
43in 520 byte sectors on disk. Data + IMD are interleaved when
44transferred between the controller and target. The T13 proposal is
45similar.
46
47Because it is highly inconvenient for operating systems to deal with
48520 (and 4104) byte sectors, we approached several HBA vendors and
49encouraged them to allow separation of the data and integrity metadata
50scatter-gather lists.
51
52The controller will interleave the buffers on write and split them on
53read. This means that the Linux can DMA the data buffers to and from
54host memory without changes to the page cache.
55
56Also, the 16-bit CRC checksum mandated by both the SCSI and SATA specs
57is somewhat heavy to compute in software. Benchmarks found that
58calculating this checksum had a significant impact on system
59performance for a number of workloads. Some controllers allow a
60lighter-weight checksum to be used when interfacing with the operating
61system. Emulex, for instance, supports the TCP/IP checksum instead.
62The IP checksum received from the OS is converted to the 16-bit CRC
63when writing and vice versa. This allows the integrity metadata to be
64generated by Linux or the application at very low cost (comparable to
65software RAID5).
66
67The IP checksum is weaker than the CRC in terms of detecting bit
68errors. However, the strength is really in the separation of the data
69buffers and the integrity metadata. These two distinct buffers much
70match up for an I/O to complete.
71
72The separation of the data and integrity metadata buffers as well as
73the choice in checksums is referred to as the Data Integrity
74Extensions. As these extensions are outside the scope of the protocol
75bodies (T10, T13), Oracle and its partners are trying to standardize
76them within the Storage Networking Industry Association.
77
78----------------------------------------------------------------------
793. KERNEL CHANGES
80
81The data integrity framework in Linux enables protection information
82to be pinned to I/Os and sent to/received from controllers that
83support it.
84
85The advantage to the integrity extensions in SCSI and SATA is that
86they enable us to protect the entire path from application to storage
87device. However, at the same time this is also the biggest
88disadvantage. It means that the protection information must be in a
89format that can be understood by the disk.
90
91Generally Linux/POSIX applications are agnostic to the intricacies of
92the storage devices they are accessing. The virtual filesystem switch
93and the block layer make things like hardware sector size and
94transport protocols completely transparent to the application.
95
96However, this level of detail is required when preparing the
97protection information to send to a disk. Consequently, the very
98concept of an end-to-end protection scheme is a layering violation.
99It is completely unreasonable for an application to be aware whether
100it is accessing a SCSI or SATA disk.
101
102The data integrity support implemented in Linux attempts to hide this
103from the application. As far as the application (and to some extent
104the kernel) is concerned, the integrity metadata is opaque information
105that's attached to the I/O.
106
107The current implementation allows the block layer to automatically
108generate the protection information for any I/O. Eventually the
109intent is to move the integrity metadata calculation to userspace for
110user data. Metadata and other I/O that originates within the kernel
111will still use the automatic generation interface.
112
113Some storage devices allow each hardware sector to be tagged with a
11416-bit value. The owner of this tag space is the owner of the block
115device. I.e. the filesystem in most cases. The filesystem can use
116this extra space to tag sectors as they see fit. Because the tag
117space is limited, the block interface allows tagging bigger chunks by
118way of interleaving. This way, 8*16 bits of information can be
119attached to a typical 4KB filesystem block.
120
121This also means that applications such as fsck and mkfs will need
122access to manipulate the tags from user space. A passthrough
123interface for this is being worked on.
124
125
126----------------------------------------------------------------------
1274. BLOCK LAYER IMPLEMENTATION DETAILS
128
1294.1 BIO
130
131The data integrity patches add a new field to struct bio when
132CONFIG_BLK_DEV_INTEGRITY is enabled. bio->bi_integrity is a pointer
133to a struct bip which contains the bio integrity payload. Essentially
134a bip is a trimmed down struct bio which holds a bio_vec containing
135the integrity metadata and the required housekeeping information (bvec
136pool, vector count, etc.)
137
138A kernel subsystem can enable data integrity protection on a bio by
139calling bio_integrity_alloc(bio). This will allocate and attach the
140bip to the bio.
141
142Individual pages containing integrity metadata can subsequently be
143attached using bio_integrity_add_page().
144
145bio_free() will automatically free the bip.
146
147
1484.2 BLOCK DEVICE
149
150Because the format of the protection data is tied to the physical
151disk, each block device has been extended with a block integrity
152profile (struct blk_integrity). This optional profile is registered
153with the block layer using blk_integrity_register().
154
155The profile contains callback functions for generating and verifying
156the protection data, as well as getting and setting application tags.
157The profile also contains a few constants to aid in completing,
158merging and splitting the integrity metadata.
159
160Layered block devices will need to pick a profile that's appropriate
161for all subdevices. blk_integrity_compare() can help with that. DM
162and MD linear, RAID0 and RAID1 are currently supported. RAID4/5/6
163will require extra work due to the application tag.
164
165
166----------------------------------------------------------------------
1675.0 BLOCK LAYER INTEGRITY API
168
1695.1 NORMAL FILESYSTEM
170
171 The normal filesystem is unaware that the underlying block device
172 is capable of sending/receiving integrity metadata. The IMD will
173 be automatically generated by the block layer at submit_bio() time
174 in case of a WRITE. A READ request will cause the I/O integrity
175 to be verified upon completion.
176
177 IMD generation and verification can be toggled using the
178
179 /sys/block/<bdev>/integrity/write_generate
180
181 and
182
183 /sys/block/<bdev>/integrity/read_verify
184
185 flags.
186
187
1885.2 INTEGRITY-AWARE FILESYSTEM
189
190 A filesystem that is integrity-aware can prepare I/Os with IMD
191 attached. It can also use the application tag space if this is
192 supported by the block device.
193
194
195 int bdev_integrity_enabled(block_device, int rw);
196
197 bdev_integrity_enabled() will return 1 if the block device
198 supports integrity metadata transfer for the data direction
199 specified in 'rw'.
200
201 bdev_integrity_enabled() honors the write_generate and
202 read_verify flags in sysfs and will respond accordingly.
203
204
205 int bio_integrity_prep(bio);
206
207 To generate IMD for WRITE and to set up buffers for READ, the
208 filesystem must call bio_integrity_prep(bio).
209
210 Prior to calling this function, the bio data direction and start
211 sector must be set, and the bio should have all data pages
212 added. It is up to the caller to ensure that the bio does not
213 change while I/O is in progress.
214
215 bio_integrity_prep() should only be called if
216 bio_integrity_enabled() returned 1.
217
218
219 int bio_integrity_tag_size(bio);
220
221 If the filesystem wants to use the application tag space it will
222 first have to find out how much storage space is available.
223 Because tag space is generally limited (usually 2 bytes per
224 sector regardless of sector size), the integrity framework
225 supports interleaving the information between the sectors in an
226 I/O.
227
228 Filesystems can call bio_integrity_tag_size(bio) to find out how
229 many bytes of storage are available for that particular bio.
230
231 Another option is bdev_get_tag_size(block_device) which will
232 return the number of available bytes per hardware sector.
233
234
235 int bio_integrity_set_tag(bio, void *tag_buf, len);
236
237 After a successful return from bio_integrity_prep(),
238 bio_integrity_set_tag() can be used to attach an opaque tag
239 buffer to a bio. Obviously this only makes sense if the I/O is
240 a WRITE.
241
242
243 int bio_integrity_get_tag(bio, void *tag_buf, len);
244
245 Similarly, at READ I/O completion time the filesystem can
246 retrieve the tag buffer using bio_integrity_get_tag().
247
248
2496.3 PASSING EXISTING INTEGRITY METADATA
250
251 Filesystems that either generate their own integrity metadata or
252 are capable of transferring IMD from user space can use the
253 following calls:
254
255
256 struct bip * bio_integrity_alloc(bio, gfp_mask, nr_pages);
257
258 Allocates the bio integrity payload and hangs it off of the bio.
259 nr_pages indicate how many pages of protection data need to be
260 stored in the integrity bio_vec list (similar to bio_alloc()).
261
262 The integrity payload will be freed at bio_free() time.
263
264
265 int bio_integrity_add_page(bio, page, len, offset);
266
267 Attaches a page containing integrity metadata to an existing
268 bio. The bio must have an existing bip,
269 i.e. bio_integrity_alloc() must have been called. For a WRITE,
270 the integrity metadata in the pages must be in a format
271 understood by the target device with the notable exception that
272 the sector numbers will be remapped as the request traverses the
273 I/O stack. This implies that the pages added using this call
274 will be modified during I/O! The first reference tag in the
275 integrity metadata must have a value of bip->bip_sector.
276
277 Pages can be added using bio_integrity_add_page() as long as
278 there is room in the bip bio_vec array (nr_pages).
279
280 Upon completion of a READ operation, the attached pages will
281 contain the integrity metadata received from the storage device.
282 It is up to the receiver to process them and verify data
283 integrity upon completion.
284
285
2866.4 REGISTERING A BLOCK DEVICE AS CAPABLE OF EXCHANGING INTEGRITY
287 METADATA
288
289 To enable integrity exchange on a block device the gendisk must be
290 registered as capable:
291
292 int blk_integrity_register(gendisk, blk_integrity);
293
294 The blk_integrity struct is a template and should contain the
295 following:
296
297 static struct blk_integrity my_profile = {
298 .name = "STANDARDSBODY-TYPE-VARIANT-CSUM",
299 .generate_fn = my_generate_fn,
300 .verify_fn = my_verify_fn,
301 .get_tag_fn = my_get_tag_fn,
302 .set_tag_fn = my_set_tag_fn,
303 .tuple_size = sizeof(struct my_tuple_size),
304 .tag_size = <tag bytes per hw sector>,
305 };
306
307 'name' is a text string which will be visible in sysfs. This is
308 part of the userland API so chose it carefully and never change
309 it. The format is standards body-type-variant.
310 E.g. T10-DIF-TYPE1-IP or T13-EPP-0-CRC.
311
312 'generate_fn' generates appropriate integrity metadata (for WRITE).
313
314 'verify_fn' verifies that the data buffer matches the integrity
315 metadata.
316
317 'tuple_size' must be set to match the size of the integrity
318 metadata per sector. I.e. 8 for DIF and EPP.
319
320 'tag_size' must be set to identify how many bytes of tag space
321 are available per hardware sector. For DIF this is either 2 or
322 0 depending on the value of the Control Mode Page ATO bit.
323
324 See 6.2 for a description of get_tag_fn and set_tag_fn.
325
326----------------------------------------------------------------------
3272007-12-24 Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/Documentation/ioctl-number.txt b/Documentation/ioctl-number.txt
index 240ce7a56c40..3bb5f466a90d 100644
--- a/Documentation/ioctl-number.txt
+++ b/Documentation/ioctl-number.txt
@@ -117,6 +117,7 @@ Code Seq# Include File Comments
117 <mailto:natalia@nikhefk.nikhef.nl> 117 <mailto:natalia@nikhefk.nikhef.nl>
118'c' 00-7F linux/comstats.h conflict! 118'c' 00-7F linux/comstats.h conflict!
119'c' 00-7F linux/coda.h conflict! 119'c' 00-7F linux/coda.h conflict!
120'c' 80-9F asm-s390/chsc.h
120'd' 00-FF linux/char/drm/drm/h conflict! 121'd' 00-FF linux/char/drm/drm/h conflict!
121'd' 00-DF linux/video_decoder.h conflict! 122'd' 00-DF linux/video_decoder.h conflict!
122'd' F0-FF linux/digi1.h 123'd' F0-FF linux/digi1.h
diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 0bbee38acd26..72aff61e7315 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -753,8 +753,11 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
753 753
754 [Multiple options for each card instance] 754 [Multiple options for each card instance]
755 model - force the model name 755 model - force the model name
756 position_fix - Fix DMA pointer (0 = auto, 1 = none, 2 = POSBUF, 3 = FIFO size) 756 position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF)
757 probe_mask - Bitmask to probe codecs (default = -1, meaning all slots) 757 probe_mask - Bitmask to probe codecs (default = -1, meaning all slots)
758 bdl_pos_adj - Specifies the DMA IRQ timing delay in samples.
759 Passing -1 will make the driver to choose the appropriate
760 value based on the controller chip.
758 761
759 [Single (global) options] 762 [Single (global) options]
760 single_cmd - Use single immediate commands to communicate with 763 single_cmd - Use single immediate commands to communicate with
@@ -845,7 +848,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
845 ALC269 848 ALC269
846 basic Basic preset 849 basic Basic preset
847 850
848 ALC662 851 ALC662/663
849 3stack-dig 3-stack (2-channel) with SPDIF 852 3stack-dig 3-stack (2-channel) with SPDIF
850 3stack-6ch 3-stack (6-channel) 853 3stack-6ch 3-stack (6-channel)
851 3stack-6ch-dig 3-stack (6-channel) with SPDIF 854 3stack-6ch-dig 3-stack (6-channel) with SPDIF
@@ -853,6 +856,10 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
853 lenovo-101e Lenovo laptop 856 lenovo-101e Lenovo laptop
854 eeepc-p701 ASUS Eeepc P701 857 eeepc-p701 ASUS Eeepc P701
855 eeepc-ep20 ASUS Eeepc EP20 858 eeepc-ep20 ASUS Eeepc EP20
859 m51va ASUS M51VA
860 g71v ASUS G71V
861 h13 ASUS H13
862 g50v ASUS G50V
856 auto auto-config reading BIOS (default) 863 auto auto-config reading BIOS (default)
857 864
858 ALC882/885 865 ALC882/885
@@ -1091,7 +1098,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
1091 This occurs when the access to non-existing or non-working codec slot 1098 This occurs when the access to non-existing or non-working codec slot
1092 (likely a modem one) causes a stall of the communication via HD-audio 1099 (likely a modem one) causes a stall of the communication via HD-audio
1093 bus. You can see which codec slots are probed by enabling 1100 bus. You can see which codec slots are probed by enabling
1094 CONFIG_SND_DEBUG_DETECT, or simply from the file name of the codec 1101 CONFIG_SND_DEBUG_VERBOSE, or simply from the file name of the codec
1095 proc files. Then limit the slots to probe by probe_mask option. 1102 proc files. Then limit the slots to probe by probe_mask option.
1096 For example, probe_mask=1 means to probe only the first slot, and 1103 For example, probe_mask=1 means to probe only the first slot, and
1097 probe_mask=4 means only the third slot. 1104 probe_mask=4 means only the third slot.
@@ -2267,6 +2274,10 @@ case above again, the first two slots are already reserved. If any
2267other driver (e.g. snd-usb-audio) is loaded before snd-interwave or 2274other driver (e.g. snd-usb-audio) is loaded before snd-interwave or
2268snd-ens1371, it will be assigned to the third or later slot. 2275snd-ens1371, it will be assigned to the third or later slot.
2269 2276
2277When a module name is given with '!', the slot will be given for any
2278modules but that name. For example, "slots=!snd-pcsp" will reserve
2279the first slot for any modules but snd-pcsp.
2280
2270 2281
2271ALSA PCM devices to OSS devices mapping 2282ALSA PCM devices to OSS devices mapping
2272======================================= 2283=======================================
diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
index b03df4d4795c..e13c4e67029f 100644
--- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
+++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl
@@ -6127,8 +6127,8 @@ struct _snd_pcm_runtime {
6127 6127
6128 <para> 6128 <para>
6129 <function>snd_printdd()</function> is compiled in only when 6129 <function>snd_printdd()</function> is compiled in only when
6130 <constant>CONFIG_SND_DEBUG_DETECT</constant> is set. Please note 6130 <constant>CONFIG_SND_DEBUG_VERBOSE</constant> is set. Please note
6131 that <constant>DEBUG_DETECT</constant> is not set as default 6131 that <constant>CONFIG_SND_DEBUG_VERBOSE</constant> is not set as default
6132 even if you configure the alsa-driver with 6132 even if you configure the alsa-driver with
6133 <option>--with-debug=full</option> option. You need to give 6133 <option>--with-debug=full</option> option. You need to give
6134 explicitly <option>--with-debug=detect</option> option instead. 6134 explicitly <option>--with-debug=detect</option> option instead.