9 files changed, 136 insertions, 65 deletions

diff --git a/Documentation/DocBook/tracepoint.tmpl b/Documentation/DocBook/tracepoint.tmpl
index 8bca1d5cec09..e8473eae2a20 100644
--- a/Documentation/DocBook/tracepoint.tmpl
+++ b/Documentation/DocBook/tracepoint.tmpl
@@ -16,6 +16,15 @@
      </address>
     </affiliation>
    </author>
+   <author>
+    <firstname>William</firstname>
+    <surname>Cohen</surname>
+    <affiliation>
+     <address>
+      <email>wcohen@redhat.com</email>
+     </address>
+    </affiliation>
+   </author>
   </authorgroup>
 
   <legalnotice>
@@ -91,4 +100,8 @@
 !Iinclude/trace/events/signal.h
   </chapter>
 
+  <chapter id="block">
+   <title>Block IO</title>
+!Iinclude/trace/events/block.h
+  </chapter>
 </book>
diff --git a/Documentation/RCU/NMI-RCU.txt b/Documentation/RCU/NMI-RCU.txt
index a6d32e65d222..a8536cb88091 100644
--- a/Documentation/RCU/NMI-RCU.txt
+++ b/Documentation/RCU/NMI-RCU.txt
@@ -34,7 +34,7 @@ NMI handler.
                 cpu = smp_processor_id();
                 ++nmi_count(cpu);
 
-                if (!rcu_dereference(nmi_callback)(regs, cpu))
+                if (!rcu_dereference_sched(nmi_callback)(regs, cpu))
                         default_do_nmi(regs);
 
                 nmi_exit();
@@ -47,12 +47,13 @@ function pointer.  If this handler returns zero, do_nmi() invokes the
 default_do_nmi() function to handle a machine-specific NMI.  Finally,
 preemption is restored.
 
-Strictly speaking, rcu_dereference() is not needed, since this code runs
-only on i386, which does not need rcu_dereference() anyway.  However,
-it is a good documentation aid, particularly for anyone attempting to
-do something similar on Alpha.
+In theory, rcu_dereference_sched() is not needed, since this code runs
+only on i386, which in theory does not need rcu_dereference_sched()
+anyway.  However, in practice it is a good documentation aid, particularly
+for anyone attempting to do something similar on Alpha or on systems
+with aggressive optimizing compilers.
 
-Quick Quiz:  Why might the rcu_dereference() be necessary on Alpha,
+Quick Quiz:  Why might the rcu_dereference_sched() be necessary on Alpha,
              given that the code referenced by the pointer is read-only?
 
 
@@ -99,17 +100,21 @@ invoke irq_enter() and irq_exit() on NMI entry and exit, respectively.
 
 Answer to Quick Quiz
 
-        Why might the rcu_dereference() be necessary on Alpha, given
+        Why might the rcu_dereference_sched() be necessary on Alpha, given
         that the code referenced by the pointer is read-only?
 
         Answer: The caller to set_nmi_callback() might well have
-                initialized some data that is to be used by the
-                new NMI handler.  In this case, the rcu_dereference()
-                would be needed, because otherwise a CPU that received
-                an NMI just after the new handler was set might see
-                the pointer to the new NMI handler, but the old
-                pre-initialized version of the handler's data.
-
-                More important, the rcu_dereference() makes it clear
-                to someone reading the code that the pointer is being
-                protected by RCU.
+                initialized some data that is to be used by the new NMI
+                handler.  In this case, the rcu_dereference_sched() would
+                be needed, because otherwise a CPU that received an NMI
+                just after the new handler was set might see the pointer
+                to the new NMI handler, but the old pre-initialized
+                version of the handler's data.
+
+                This same sad story can happen on other CPUs when using
+                a compiler with aggressive pointer-value speculation
+                optimizations.
+
+                More important, the rcu_dereference_sched() makes it
+                clear to someone reading the code that the pointer is
+                being protected by RCU-sched.
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index cbc180f90194..790d1a812376 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -260,7 +260,8 @@ over a rather long period of time, but improvements are always welcome!
         The reason that it is permissible to use RCU list-traversal
         primitives when the update-side lock is held is that doing so
         can be quite helpful in reducing code bloat when common code is
-        shared between readers and updaters.
+        shared between readers and updaters.  Additional primitives
+        are provided for this case, as discussed in lockdep.txt.
 
 10.     Conversely, if you are in an RCU read-side critical section,
         and you don't hold the appropriate update-side lock, you -must-
@@ -344,8 +345,8 @@ over a rather long period of time, but improvements are always welcome!
         requiring SRCU's read-side deadlock immunity or low read-side
         realtime latency.
 
-        Note that, rcu_assign_pointer() and rcu_dereference() relate to
-        SRCU just as they do to other forms of RCU.
+        Note that, rcu_assign_pointer() relates to SRCU just as they do
+        to other forms of RCU.
 
 15.     The whole point of call_rcu(), synchronize_rcu(), and friends
         is to wait until all pre-existing readers have finished before
diff --git a/Documentation/RCU/lockdep.txt b/Documentation/RCU/lockdep.txt
index fe24b58627bd..d7a49b2f6994 100644
--- a/Documentation/RCU/lockdep.txt
+++ b/Documentation/RCU/lockdep.txt
@@ -32,9 +32,20 @@ checking of rcu_dereference() primitives:
         srcu_dereference(p, sp):
                 Check for SRCU read-side critical section.
         rcu_dereference_check(p, c):
-                Use explicit check expression "c".
+                Use explicit check expression "c".  This is useful in
+                code that is invoked by both readers and updaters.
         rcu_dereference_raw(p)
                 Don't check.  (Use sparingly, if at all.)
+        rcu_dereference_protected(p, c):
+                Use explicit check expression "c", and omit all barriers
+                and compiler constraints.  This is useful when the data
+                structure cannot change, for example, in code that is
+                invoked only by updaters.
+        rcu_access_pointer(p):
+                Return the value of the pointer and omit all barriers,
+                but retain the compiler constraints that prevent duplicating
+                or coalescsing.  This is useful when when testing the
+                value of the pointer itself, for example, against NULL.
 
 The rcu_dereference_check() check expression can be any boolean
 expression, but would normally include one of the rcu_read_lock_held()
@@ -59,7 +70,20 @@ In case (1), the pointer is picked up in an RCU-safe manner for vanilla
 RCU read-side critical sections, in case (2) the ->file_lock prevents
 any change from taking place, and finally, in case (3) the current task
 is the only task accessing the file_struct, again preventing any change
-from taking place.
+from taking place.  If the above statement was invoked only from updater
+code, it could instead be written as follows:
+
+        file = rcu_dereference_protected(fdt->fd[fd],
+                                         lockdep_is_held(&files->file_lock) ||
+                                         atomic_read(&files->count) == 1);
+
+This would verify cases #2 and #3 above, and furthermore lockdep would
+complain if this was used in an RCU read-side critical section unless one
+of these two cases held.  Because rcu_dereference_protected() omits all
+barriers and compiler constraints, it generates better code than do the
+other flavors of rcu_dereference().  On the other hand, it is illegal
+to use rcu_dereference_protected() if either the RCU-protected pointer
+or the RCU-protected data that it points to can change concurrently.
 
 There are currently only "universal" versions of the rcu_assign_pointer()
 and RCU list-/tree-traversal primitives, which do not (yet) check for
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 1dc00ee97163..cfaac34c4557 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -840,6 +840,12 @@ SRCU:	Initialization/cleanup
         init_srcu_struct
         cleanup_srcu_struct
 
+All:  lockdep-checked RCU-protected pointer access
+
+        rcu_dereference_check
+        rcu_dereference_protected
+        rcu_access_pointer
+
 See the comment headers in the source code (or the docbook generated
 from them) for more information.
 
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 6fab97ea7e6b..508b5b2b0289 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -1162,8 +1162,8 @@ where a driver received a request ala this before:
 
 As mentioned, there is no virtual mapping of a bio. For DMA, this is
 not a problem as the driver probably never will need a virtual mapping.
-Instead it needs a bus mapping (pci_map_page for a single segment or
-use blk_rq_map_sg for scatter gather) to be able to ship it to the driver. For
+Instead it needs a bus mapping (dma_map_page for a single segment or
+use dma_map_sg for scatter gather) to be able to ship it to the driver. For
 PIO drivers (or drivers that need to revert to PIO transfer once in a
 while (IDE for example)), where the CPU is doing the actual data
 transfer a virtual mapping is needed. If the driver supports highmem I/O,
diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt
index 8490480ce432..c0fc1c75fd88 100644
--- a/Documentation/input/multi-touch-protocol.txt
+++ b/Documentation/input/multi-touch-protocol.txt
@@ -68,6 +68,22 @@ like:
    SYN_MT_REPORT
    SYN_REPORT
 
+Here is the sequence after lifting one of the fingers:
+
+   ABS_MT_POSITION_X
+   ABS_MT_POSITION_Y
+   SYN_MT_REPORT
+   SYN_REPORT
+
+And here is the sequence after lifting the remaining finger:
+
+   SYN_MT_REPORT
+   SYN_REPORT
+
+If the driver reports one of BTN_TOUCH or ABS_PRESSURE in addition to the
+ABS_MT events, the last SYN_MT_REPORT event may be omitted. Otherwise, the
+last SYN_REPORT will be dropped by the input core, resulting in no
+zero-finger event reaching userland.
 
 Event Semantics
 ---------------
@@ -217,11 +233,6 @@ where examples can be found.
 difference between the contact position and the approaching tool position
 could be used to derive tilt.
 [2] The list can of course be extended.
-[3] The multi-touch X driver is currently in the prototyping stage. At the
-time of writing (April 2009), the MT protocol is not yet merged, and the
-prototype implements finger matching, basic mouse support and two-finger
-scrolling. The project aims at improving the quality of current multi-touch
-functionality available in the Synaptics X driver, and in addition
-implement more advanced gestures.
+[3] Multitouch X driver project: http://bitmath.org/code/multitouch/.
 [4] See the section on event computation.
 [5] See the section on finger tracking.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e4cbca58536c..e2202e93b148 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -320,11 +320,6 @@ and is between 256 and 4096 characters. It is defined in the file
         amd_iommu=      [HW,X86-84]
                         Pass parameters to the AMD IOMMU driver in the system.
                         Possible values are:
-                        isolate - enable device isolation (each device, as far
-                                  as possible, will get its own protection
-                                  domain) [default]
-                        share - put every device behind one IOMMU into the
-                                same protection domain
                         fullflush - enable flushing of IO/TLB entries when
                                     they are unmapped. Otherwise they are
                                     flushed before they will be reused, which
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 0e58b4539176..e8c8f4f06c67 100644
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -41,11 +41,12 @@ SOF_TIMESTAMPING_SOFTWARE:     return system time stamp generated in
 SOF_TIMESTAMPING_TX/RX determine how time stamps are generated.
 SOF_TIMESTAMPING_RAW/SYS determine how they are reported in the
 following control message:
-    struct scm_timestamping {
-           struct timespec systime;
-           struct timespec hwtimetrans;
-           struct timespec hwtimeraw;
-    };
+
+struct scm_timestamping {
+        struct timespec systime;
+        struct timespec hwtimetrans;
+        struct timespec hwtimeraw;
+};
 
 recvmsg() can be used to get this control message for regular incoming
 packets. For send time stamps the outgoing packet is looped back to
@@ -87,12 +88,13 @@ by the network device and will be empty without that support.
 SIOCSHWTSTAMP:
 
 Hardware time stamping must also be initialized for each device driver
-that is expected to do hardware time stamping. The parameter is:
+that is expected to do hardware time stamping. The parameter is defined in
+/include/linux/net_tstamp.h as:
 
 struct hwtstamp_config {
-    int flags;           /* no flags defined right now, must be zero */
-    int tx_type;         /* HWTSTAMP_TX_* */
-    int rx_filter;       /* HWTSTAMP_FILTER_* */
+        int flags;      /* no flags defined right now, must be zero */
+        int tx_type;    /* HWTSTAMP_TX_* */
+        int rx_filter;  /* HWTSTAMP_FILTER_* */
 };
 
 Desired behavior is passed into the kernel and to a specific device by
@@ -139,42 +141,56 @@ enum {
         /* time stamp any incoming packet */
         HWTSTAMP_FILTER_ALL,
 
-        /* return value: time stamp all packets requested plus some others */
-        HWTSTAMP_FILTER_SOME,
+        /* return value: time stamp all packets requested plus some others */
+        HWTSTAMP_FILTER_SOME,
 
         /* PTP v1, UDP, any kind of event packet */
         HWTSTAMP_FILTER_PTP_V1_L4_EVENT,
 
-        ...
+        /* for the complete list of values, please check
+         * the include file /include/linux/net_tstamp.h
+         */
 };
 
 
 DEVICE IMPLEMENTATION
 
 A driver which supports hardware time stamping must support the
-SIOCSHWTSTAMP ioctl. Time stamps for received packets must be stored
-in the skb with skb_hwtstamp_set().
+SIOCSHWTSTAMP ioctl and update the supplied struct hwtstamp_config with
+the actual values as described in the section on SIOCSHWTSTAMP.
+
+Time stamps for received packets must be stored in the skb. To get a pointer
+to the shared time stamp structure of the skb call skb_hwtstamps(). Then
+set the time stamps in the structure:
+
+struct skb_shared_hwtstamps {
+        /* hardware time stamp transformed into duration
+         * since arbitrary point in time
+         */
+        ktime_t hwtstamp;
+        ktime_t syststamp; /* hwtstamp transformed to system time base */
+};
 
 Time stamps for outgoing packets are to be generated as follows:
-- In hard_start_xmit(), check if skb_hwtstamp_check_tx_hardware()
-  returns non-zero. If yes, then the driver is expected
-  to do hardware time stamping.
+- In hard_start_xmit(), check if skb_tx(skb)->hardware is set no-zero.
+  If yes, then the driver is expected to do hardware time stamping.
 - If this is possible for the skb and requested, then declare
-  that the driver is doing the time stamping by calling
-  skb_hwtstamp_tx_in_progress(). A driver not supporting
-  hardware time stamping doesn't do that. A driver must never
-  touch sk_buff::tstamp! It is used to store how time stamping
-  for an outgoing packets is to be done.
+  that the driver is doing the time stamping by setting the field
+  skb_tx(skb)->in_progress non-zero. You might want to keep a pointer
+  to the associated skb for the next step and not free the skb. A driver
+  not supporting hardware time stamping doesn't do that. A driver must
+  never touch sk_buff::tstamp! It is used to store software generated
+  time stamps by the network subsystem.
 - As soon as the driver has sent the packet and/or obtained a
   hardware time stamp for it, it passes the time stamp back by
   calling skb_hwtstamp_tx() with the original skb, the raw
-  hardware time stamp and a handle to the device (necessary
-  to convert the hardware time stamp to system time). If obtaining
-  the hardware time stamp somehow fails, then the driver should
-  not fall back to software time stamping. The rationale is that
-  this would occur at a later time in the processing pipeline
-  than other software time stamping and therefore could lead
-  to unexpected deltas between time stamps.
-- If the driver did not call skb_hwtstamp_tx_in_progress(), then
+  hardware time stamp. skb_hwtstamp_tx() clones the original skb and
+  adds the timestamps, therefore the original skb has to be freed now.
+  If obtaining the hardware time stamp somehow fails, then the driver
+  should not fall back to software time stamping. The rationale is that
+  this would occur at a later time in the processing pipeline than other
+  software time stamping and therefore could lead to unexpected deltas
+  between time stamps.
+- If the driver did not call set skb_tx(skb)->in_progress, then
   dev_hard_start_xmit() checks whether software time stamping
   is wanted as fallback and potentially generates the time stamp.