diff options
| author | Bart Van Assche <bvanassche@acm.org> | 2021-08-09 16:03:04 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-08 08:44:28 +0100 |
| commit | df0110425f42b7462a657dadb309a67ebf9c8d58 (patch) | |
| tree | 9b89a5359f35390495f900f19fe92b8c3d9cf3ae | |
| parent | 66cd6055304550f6ab47672c5e42cec5b79295e2 (diff) | |
scsi: core: Introduce the scsi_cmd_to_rq() function
[ Upstream commit 51f3a478892873337c54068d1185bcd797000a52 ]
The 'request' member of struct scsi_cmnd is superfluous. The struct request
and struct scsi_cmnd data structures are adjacent and hence the request
pointer can be derived easily from a scsi_cmnd pointer. Introduce a helper
function that performs that conversion in a type-safe way. This patch is
the first step towards removing the request member from struct
scsi_cmnd. Making that change has the following advantages:
- This is a performance optimization since adding an offset to a pointer
takes less time than dereferencing a pointer.
- struct scsi_cmnd becomes smaller.
Link: https://lore.kernel.org/r/20210809230355.8186-2-bvanassche@acm.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Stable-dep-of: 19597cad64d6 ("scsi: qla2xxx: Fix system crash due to bad pointer access")
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | include/scsi/scsi_cmnd.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 7738a055d953..dafde3d764d0 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -143,6 +143,12 @@ struct scsi_cmnd { unsigned char tag; /* SCSI-II queued command tag */ }; +/* Variant of blk_mq_rq_from_pdu() that verifies the type of its argument. */ +static inline struct request *scsi_cmd_to_rq(struct scsi_cmnd *scmd) +{ + return blk_mq_rq_from_pdu(scmd); +} + /* * Return the driver private allocation behind the command. * Only works if cmd_size is set in the host template. |