block,scsi: fixup blk_get_request dead queue scenarios
authorJoe Lawrence <joe.lawrence@stratus.com>
Thu, 28 Aug 2014 14:15:21 +0000 (08:15 -0600)
committerJens Axboe <axboe@fb.com>
Thu, 28 Aug 2014 16:03:46 +0000 (10:03 -0600)
commita492f075450f3ba87de36e5ffe92a9d0c7af9723
tree61960a71c7fde0eee3d77cda460154d2f7715d2f
parenteb571eeade2598635f813b3284d02c13a380301e
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>
20 files changed:
block/blk-core.c
block/blk-mq.c
block/bsg.c
block/scsi_ioctl.c
drivers/block/paride/pd.c
drivers/block/pktcdvd.c
drivers/block/sx8.c
drivers/cdrom/cdrom.c
drivers/ide/ide-park.c
drivers/scsi/device_handler/scsi_dh_alua.c
drivers/scsi/device_handler/scsi_dh_emc.c
drivers/scsi/device_handler/scsi_dh_hp_sw.c
drivers/scsi/device_handler/scsi_dh_rdac.c
drivers/scsi/osd/osd_initiator.c
drivers/scsi/osst.c
drivers/scsi/scsi_error.c
drivers/scsi/scsi_lib.c
drivers/scsi/sg.c
drivers/scsi/st.c
drivers/target/target_core_pscsi.c