On 14-08-22 03:53 PM, Tony Battersby wrote:
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@xxxxxxxxxxxxxxx>
Tested-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Patch tested on lk 3.17-rc1 with the sg driver using
the READ(32) command.
For inclusion in 3.17 only.
May want to check if blk-mq work in lk 3.16 and earlier
breaks the bsg driver's capability to send SCSI cdbs
that are longer than 16 bytes.
diff -urpN linux-3.17.0-rc1-a/block/blk-core.c linux-3.17.0-rc1-b/block/blk-core.c
--- linux-3.17.0-rc1-a/block/blk-core.c 2014-08-16 12:40:26.000000000 -0400
+++ linux-3.17.0-rc1-b/block/blk-core.c 2014-08-22 14:03:33.000000000 -0400
@@ -1252,7 +1252,6 @@ void blk_rq_set_block_pc(struct request
rq->__sector = (sector_t) -1;
rq->bio = rq->biotail = NULL;
memset(rq->__cmd, 0, sizeof(rq->__cmd));
- rq->cmd = rq->__cmd;
}
EXPORT_SYMBOL(blk_rq_set_block_pc);
diff -urpN linux-3.17.0-rc1-a/block/blk-mq.c linux-3.17.0-rc1-b/block/blk-mq.c
--- linux-3.17.0-rc1-a/block/blk-mq.c 2014-08-16 12:40:26.000000000 -0400
+++ linux-3.17.0-rc1-b/block/blk-mq.c 2014-08-22 14:02:32.000000000 -0400
@@ -172,6 +172,8 @@ static void blk_mq_rq_ctx_init(struct re
/* tag was already set */
rq->errors = 0;
+ rq->cmd = rq->__cmd;
+
rq->extra_len = 0;
rq->sense_len = 0;
rq->resid_len = 0;
diff -urpN linux-3.17.0-rc1-a/drivers/scsi/scsi_lib.c linux-3.17.0-rc1-b/drivers/scsi/scsi_lib.c
--- linux-3.17.0-rc1-a/drivers/scsi/scsi_lib.c 2014-08-16 12:40:26.000000000 -0400
+++ linux-3.17.0-rc1-b/drivers/scsi/scsi_lib.c 2014-08-22 14:02:32.000000000 -0400
@@ -1808,7 +1808,6 @@ static int scsi_mq_prep_fn(struct reques
cmd->tag = req->tag;
- req->cmd = req->__cmd;
cmd->cmnd = req->cmd;
cmd->prot_op = SCSI_PROT_NORMAL;
--
--
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