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Commit 6f4a1626 authored by Tony Battersby's avatar Tony Battersby Committed by Jens Axboe
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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: default avatarTony Battersby <tonyb@cybernetics.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent a57821ca

block/blk-core.c

+0 −1
Original line number Diff line number Diff line
@@ -1252,7 +1252,6 @@ void blk_rq_set_block_pc(struct request *rq) 
	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);

block/blk-mq.c

+2 −0
Original line number Diff line number Diff line
@@ -176,6 +176,8 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx, 
	/* tag was already set */

	rq->errors = 0;



	rq->cmd = rq->__cmd;



	rq->extra_len = 0;

	rq->sense_len = 0;

	rq->resid_len = 0;

drivers/scsi/scsi_lib.c

+0 −1
Original line number Diff line number Diff line
@@ -1808,7 +1808,6 @@ static int scsi_mq_prep_fn(struct request *req) 


	cmd->tag = req->tag;



	req->cmd = req->__cmd;

	cmd->cmnd = req->cmd;

	cmd->prot_op = SCSI_PROT_NORMAL;