Merge tag 'md/3.19-fixes' of git://neil.brown.name/md

Pull two fixes for md from Neil Brown:

 - Another live lock, needs backporting

 - work-around false positive with new warnings.

* tag 'md/3.19-fixes' of git://neil.brown.name/md:
  md/bitmap: fix a might_sleep() warning.
  md/raid5: fix another livelock caused by non-aligned writes.

2 files changed, 18 insertions, 0 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index da3604e73e8a..1695ee5f3ffc 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -72,6 +72,19 @@ __acquires(bitmap->lock)
         /* this page has not been allocated yet */
 
         spin_unlock_irq(&bitmap->lock);
+        /* It is possible that this is being called inside a
+         * prepare_to_wait/finish_wait loop from raid5c:make_request().
+         * In general it is not permitted to sleep in that context as it
+         * can cause the loop to spin freely.
+         * That doesn't apply here as we can only reach this point
+         * once with any loop.
+         * When this function completes, either bp[page].map or
+         * bp[page].hijacked.  In either case, this function will
+         * abort before getting to this point again.  So there is
+         * no risk of a free-spin, and so it is safe to assert
+         * that sleeping here is allowed.
+         */
+        sched_annotate_sleep();
         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
         spin_lock_irq(&bitmap->lock);
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c1b0d52bfcb0..b98765f6f77f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3195,6 +3195,11 @@ static void handle_stripe_dirtying(struct r5conf *conf,
                                           (unsigned long long)sh->sector,
                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
         }
+
+        if (rcw > disks && rmw > disks &&
+            !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+                set_bit(STRIPE_DELAYED, &sh->state);
+
         /* now if nothing is locked, and if we have enough data,
          * we can start a write request
          */