diff mbox series

[v3,01/51] core: Introduce the scsi_cmd_to_rq() function

Message ID	20210524030856.2824-2-bvanassche@acm.org
State	Superseded
Headers	show Return-Path: <linux-scsi-owner@kernel.org> From: Bart Van Assche <bvanassche@acm.org> To: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Christoph Hellwig <hch@lst.de>, linux-scsi@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>, Hannes Reinecke <hare@suse.de>, Ming Lei <ming.lei@redhat.com>, "James E.J. Bottomley" <jejb@linux.ibm.com> Subject: [PATCH v3 01/51] core: Introduce the scsi_cmd_to_rq() function Date: Sun, 23 May 2021 20:08:06 -0700 Message-Id: <20210524030856.2824-2-bvanassche@acm.org> In-Reply-To: <20210524030856.2824-1-bvanassche@acm.org> References: <20210524030856.2824-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Remove the request pointer from struct scsi_cmnd \| expand [v3,00/51] Remove the request pointer from struct scsi_cmnd [v3,01/51] core: Introduce the scsi_cmd_to_rq() function [v3,02/51] core: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,03/51] sd: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,04/51] sr: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,05/51] scsi_transport_fc: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,06/51] scsi_transport_spi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,07/51] ata: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,08/51] RDMA/iser: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,09/51] RDMA/srp: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,10/51] zfcp: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,11/51] 53c700: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,12/51] NCR5380: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,13/51] aacraid: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,14/51] advansys: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,15/51] aha1542: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,16/51] bnx2i: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,17/51] csiostor: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,18/51] cxlflash: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,19/51] dpt_i2o: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,20/51] fnic: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,21/51] hisi_sas: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,22/51] hpsa: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,23/51] ibmvfc: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,24/51] ibmvscsi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,25/51] ips: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,26/51] libsas: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,27/51] lpfc: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,28/51] megaraid: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,29/51] mpt3sas: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,30/51] mvumi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,31/51] myrb: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,32/51] myrs: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,33/51] ncr53c8xx: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,34/51] qedf: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,35/51] qedi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,36/51] qla1280: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,37/51] qla2xxx: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,38/51] qla4xxx: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,39/51] qlogicpti: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,40/51] scsi_debug: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,41/51] smartpqi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,42/51] snic: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,43/51] stex: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,44/51] sun3_scsi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,45/51] sym53c8xx: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,46/51] ufs: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,47/51] virtio_scsi: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,48/51] xen-scsifront: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,49/51] tcm_loop: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,50/51] usb-storage: Use scsi_cmd_to_rq() instead of scsi_cmnd.request [v3,51/51] core: Remove the request member from struct scsi_cmnd

Commit Message

Bart Van Assche May 24, 2021, 3:08 a.m. UTC

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.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 include/scsi/scsi_cmnd.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff mbox series

Patch

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index fed024f4c02a..6787670d0d16 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -146,6 +146,12 @@  struct scsi_cmnd {
 	unsigned int extra_len;	/* length of alignment and padding */
 };
 
+/* 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.