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author | NeilBrown <neilb@suse.de> | 2015-02-02 17:08:03 +1100 |
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committer | NeilBrown <neilb@suse.de> | 2015-02-02 17:08:03 +1100 |
commit | d95901433436aeb921eac58bfd8a2aa77f110384 (patch) | |
tree | b8660a180b96758f2652da4ae0276dc04996fbf5 | |
parent | b1b02fe97f75b12ab34b2303bfd4e3526d903a58 (diff) | |
download | linux-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>
-rw-r--r-- | drivers/md/bitmap.c | 13 |
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); |