From: NeilBrown Date: Mon, 2 Feb 2015 06:08:03 +0000 (+1100) Subject: md/bitmap: fix a might_sleep() warning. X-Git-Tag: v3.19~21^2 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=d95901433436aeb921eac58bfd8a2aa77f110384;p=~emulex%2Finfiniband.git 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 Signed-off-by: NeilBrown --- diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index da3604e73e8..1695ee5f3ff 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);