scsi-mq: fix requests that use a separate CDB buffer
This patch fixes code such as the following with scsi-mq enabled:
rq = blk_get_request(...);
blk_rq_set_block_pc(rq);
rq->cmd = my_cmd_buffer; /* separate CDB buffer */
blk_execute_rq_nowait(...);
Code like this appears in e.g. sg_start_req() in drivers/scsi/sg.c (for
large CDBs only). Without this patch, scsi_mq_prep_fn() will set
rq->cmd back to rq->__cmd, causing the wrong CDB to be sent to the device.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7950f8d..4aac826 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -176,6 +176,8 @@
/* tag was already set */
rq->errors = 0;
+ rq->cmd = rq->__cmd;
+
rq->extra_len = 0;
rq->sense_len = 0;
rq->resid_len = 0;