This is a note to let you know that I've just added the patch titled
scsi: core: Introduce the scsi_cmd_to_rq() function
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-core-introduce-the-scsi_cmd_to_rq-function.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d0f346c9e21dbd4dc404d9a10e313ed95318386a
Author: Bart Van Assche <bvanassche@xxxxxxx>
Date: Mon Aug 9 16:03:04 2021 -0700
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@xxxxxxx
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Stable-dep-of: 19597cad64d6 ("scsi: qla2xxx: Fix system crash due to bad pointer access")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 7738a055d9535..dafde3d764d03 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.
