Messages in this thread | | | Date | Sat, 23 Aug 2014 15:09:32 -0400 | From | Douglas Gilbert <> | Subject | Re: [PATCH][SCSI] scsi-mq: fix requests that use a separate CDB buffer |
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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@cybernetics.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
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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