tree 61960a71c7fde0eee3d77cda460154d2f7715d2f
parent eb571eeade2598635f813b3284d02c13a380301e
author Joe Lawrence <joe.lawrence@stratus.com> 1409235321 -0600
committer Jens Axboe <axboe@fb.com> 1409241826 -0600

block,scsi: fixup blk_get_request dead queue scenarios

The blk_get_request function may fail in low-memory conditions or during
device removal (even if __GFP_WAIT is set). To distinguish between these
errors, modify the blk_get_request call stack to return the appropriate
ERR_PTR. Verify that all callers check the return status and consider
IS_ERR instead of a simple NULL pointer check.

For consistency, make a similar change to the blk_mq_alloc_request leg
of blk_get_request.  It may fail if the queue is dead, or the caller was
unwilling to wait.

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>