Merge tag 'md/3.13' of git://neil.brown.name/md

Pull md update from Neil Brown:
 "Mostly optimisations and obscure bug fixes.
   - raid5 gets less lock contention
   - raid1 gets less contention between normal-io and resync-io during
     resync"

* tag 'md/3.13' of git://neil.brown.name/md:
  md/raid5: Use conf->device_lock protect changing of multi-thread resources.
  md/raid5: Before freeing old multi-thread worker, it should flush them.
  md/raid5: For stripe with R5_ReadNoMerge, we replace REQ_FLUSH with REQ_NOMERGE.
  UAPI: include <asm/byteorder.h> in linux/raid/md_p.h
  raid1: Rewrite the implementation of iobarrier.
  raid1: Add some macros to make code clearly.
  raid1: Replace raise_barrier/lower_barrier with freeze_array/unfreeze_array when reconfiguring the array.
  raid1: Add a field array_frozen to indicate whether raid in freeze state.
  md: Convert use of typedef ctl_table to struct ctl_table
  md/raid5: avoid deadlock when raid5 array has unack badblocks during md_stop_writes.
  md: use MD_RECOVERY_INTR instead of kthread_should_stop in resync thread.
  md: fix some places where mddev_lock return value is not checked.
  raid5: Retry R5_ReadNoMerge flag when hit a read error.
  raid5: relieve lock contention in get_active_stripe()
  raid5: relieve lock contention in get_active_stripe()
  wait: add wait_event_cmd()
  md/raid5.c: add proper locking to error path of raid5_start_reshape.
  md: fix calculation of stacking limits on level change.
  raid5: Use slow_path to release stripe when mddev->thread is null

1 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 61939ba30aa0..eaa00b10abaa 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -278,6 +278,31 @@ do {									\
         __ret;                                                          \
 })
 
+#define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
+        (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
+                            cmd1; schedule(); cmd2)
+
+/**
+ * wait_event_cmd - sleep until a condition gets true
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * cmd1: the command will be executed before sleep
+ * cmd2: the command will be executed after sleep
+ *
+ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
+ * @condition evaluates to true. The @condition is checked each time
+ * the waitqueue @wq is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ */
+#define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
+do {                                                                    \
+        if (condition)                                                  \
+                break;                                                  \
+        __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
+} while (0)
+
 #define __wait_event_interruptible(wq, condition)                       \
         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
                       schedule())