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authorNeilBrown <neilb@suse.de>2015-02-02 17:08:03 +1100
committerNeilBrown <neilb@suse.de>2015-02-02 17:08:03 +1100
commitd95901433436aeb921eac58bfd8a2aa77f110384 (patch)
treeb8660a180b96758f2652da4ae0276dc04996fbf5 /drivers
parentb1b02fe97f75b12ab34b2303bfd4e3526d903a58 (diff)
downloadlinux-d95901433436aeb921eac58bfd8a2aa77f110384.tar.bz2
md/bitmap: fix a might_sleep() warning.
commit 8eb23b9f35aae413140d3fda766a98092c21e9b0 sched: Debug nested sleeps causes false-positive warnings in RAID5 code. This annotation removes them and adds a comment explaining why there is no real problem. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/bitmap.c13
1 files changed, 13 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);