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

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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: John Garry <john.g.garry@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251031204029.2883185-7-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Hannes Reinecke
2025-10-31 13:39:14 -07:00
committed by Martin K. Petersen
parent 11ea1de3fc
commit a2ab4e3328
2 changed files with 42 additions and 0 deletions
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38
drivers/scsi/scsi_lib.c
View File

@@ -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

4
include/scsi/scsi_device.h
View File

@@ -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);