Commit a2ab4e33 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Martin K. Petersen
Browse files

scsi: core: Add scsi_{get,put}_internal_cmd() helpers 

Add helper functions to allow LLDDs to allocate and free internal commands.

[ bvanassche: changed the 'nowait' argument into a 'flags' argument. See also
  https://lore.kernel.org/linux-scsi/20211125151048.103910-3-hare@suse.de/

 ]

Reviewed-by: default avatarJohn Garry <john.g.garry@oracle.com>
Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251031204029.2883185-7-bvanassche@acm.org


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 11ea1de3

drivers/scsi/scsi_lib.c

+38 −0
Original line number Diff line number Diff line
@@ -2134,6 +2134,44 @@ void scsi_mq_free_tags(struct kref *kref) 
	complete(&shost->tagset_freed);

}



/**

 * scsi_get_internal_cmd() - Allocate an internal SCSI command.

 * @sdev: SCSI device from which to allocate the command

 * @data_direction: Data direction for the allocated command

 * @flags: request allocation flags, e.g. BLK_MQ_REQ_RESERVED or

 *	BLK_MQ_REQ_NOWAIT.

 *

 * Allocates a SCSI command for internal LLDD use.

 */

struct scsi_cmnd *scsi_get_internal_cmd(struct scsi_device *sdev,

					enum dma_data_direction data_direction,

					blk_mq_req_flags_t flags)

{

	enum req_op op = data_direction == DMA_TO_DEVICE ? REQ_OP_DRV_OUT :

							   REQ_OP_DRV_IN;

	struct scsi_cmnd *scmd;

	struct request *rq;



	rq = scsi_alloc_request(sdev->request_queue, op, flags);

	if (IS_ERR(rq))

		return NULL;

	scmd = blk_mq_rq_to_pdu(rq);

	scmd->device = sdev;



	return scmd;

}

EXPORT_SYMBOL_GPL(scsi_get_internal_cmd);



/**

 * scsi_put_internal_cmd() - Free an internal SCSI command.

 * @scmd: SCSI command to be freed

 */

void scsi_put_internal_cmd(struct scsi_cmnd *scmd)

{

	blk_mq_free_request(blk_mq_rq_from_pdu(scmd));

}

EXPORT_SYMBOL_GPL(scsi_put_internal_cmd);



/**

 * scsi_device_from_queue - return sdev associated with a request_queue

 * @q: The request queue to return the sdev from

include/scsi/scsi_device.h

+4 −0
Original line number Diff line number Diff line
@@ -558,6 +558,10 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, 
		     const struct scsi_exec_args *args);

void scsi_failures_reset_retries(struct scsi_failures *failures);



struct scsi_cmnd *scsi_get_internal_cmd(struct scsi_device *sdev,

					enum dma_data_direction data_direction,

					blk_mq_req_flags_t flags);

void scsi_put_internal_cmd(struct scsi_cmnd *scmd);

extern void sdev_disable_disk_events(struct scsi_device *sdev);

extern void sdev_enable_disk_events(struct scsi_device *sdev);

extern int scsi_vpd_lun_id(struct scsi_device *, char *, size_t);