fnic: reject device resets without assigned tags for the blk-mq case

Current the midlayer fakes up a struct request for the explicit reset
ioctls, and those don't have a tag allocated to them.  The fnic driver pokes
into midlayer structures to paper over this design issue, but that won't
work for the blk-mq case.

Either someone who can actually test the hardware will have to come up with
a similar hack for the blk-mq case, or we'll have to bite the bullet and fix
the way the EH ioctls work for real, but until that happens we fail these
explicit requests here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
Cc: Hiral Patel <hiralpat@cisco.com>
Cc: Suma Ramars <sramars@cisco.com>
Cc: Brian Uchino <buchino@cisco.com>

diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c
index 3f88f56..961bdf5 100644 (file)
--- a/drivers/scsi/fnic/fnic_scsi.c
+++ b/drivers/scsi/fnic/fnic_scsi.c
@@ -2224,6 +2224,22 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 
        tag = sc->request->tag;
        if (unlikely(tag < 0)) {
+               /*
+                * XXX(hch): current the midlayer fakes up a struct
+                * request for the explicit reset ioctls, and those
+                * don't have a tag allocated to them.  The below
+                * code pokes into midlayer structures to paper over
+                * this design issue, but that won't work for blk-mq.
+                *
+                * Either someone who can actually test the hardware
+                * will have to come up with a similar hack for the
+                * blk-mq case, or we'll have to bite the bullet and
+                * fix the way the EH ioctls work for real, but until
+                * that happens we fail these explicit requests here.
+                */
+               if (shost_use_blk_mq(sc->device->host))
+                       goto fnic_device_reset_end;
+
                tag = fnic_scsi_host_start_tag(fnic, sc);
                if (unlikely(tag == SCSI_NO_TAG))
                        goto fnic_device_reset_end;