block: add proper state guards to __elv_next_request
authorJames Bottomley <James.Bottomley@suse.de>
Wed, 18 May 2011 14:20:10 +0000 (16:20 +0200)
committerJens Axboe <jaxboe@fusionio.com>
Wed, 18 May 2011 17:30:32 +0000 (19:30 +0200)
commit0a58e077eb600d1efd7e54ad9926a75a39d7f8ae
treeeb1b325d28c0aa44b1dba3bdb0b31b662b2a1f7f
parenta2b9c1f6208126e6df6c02428c501f8853685812
block: add proper state guards to __elv_next_request

blk_cleanup_queue() calls elevator_exit() and after this, we can't
touch the elevator without oopsing.  __elv_next_request() must check
for this state because in the refcounted queue model, we can still
call it after blk_cleanup_queue() has been called.

This was reported as causing an oops attributable to scsi.

Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
block/blk.h