mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
ee1b6f7aff
The libata tag allocation is using a round-robin policy. Next patch will make libata use block generic tag allocation, so let's add a policy to tag allocation. Currently two policies: FIFO (default) and round-robin. Cc: Jens Axboe <axboe@fb.com> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
#ifndef _SCSI_SCSI_TCQ_H
|
|
#define _SCSI_SCSI_TCQ_H
|
|
|
|
#include <linux/blkdev.h>
|
|
#include <scsi/scsi_cmnd.h>
|
|
#include <scsi/scsi_device.h>
|
|
#include <scsi/scsi_host.h>
|
|
|
|
#define SCSI_NO_TAG (-1) /* identify no tag in use */
|
|
|
|
|
|
#ifdef CONFIG_BLOCK
|
|
static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
|
|
int unique_tag)
|
|
{
|
|
u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
|
|
struct request *req = NULL;
|
|
|
|
if (hwq < shost->tag_set.nr_hw_queues)
|
|
req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
|
|
blk_mq_unique_tag_to_tag(unique_tag));
|
|
return req ? (struct scsi_cmnd *)req->special : NULL;
|
|
}
|
|
|
|
/**
|
|
* scsi_find_tag - find a tagged command by device
|
|
* @SDpnt: pointer to the ScSI device
|
|
* @tag: tag generated by blk_mq_unique_tag()
|
|
*
|
|
* Notes:
|
|
* Only works with tags allocated by the generic blk layer.
|
|
**/
|
|
static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
|
|
{
|
|
struct request *req;
|
|
|
|
if (tag != SCSI_NO_TAG) {
|
|
if (shost_use_blk_mq(sdev->host))
|
|
return scsi_mq_find_tag(sdev->host, tag);
|
|
|
|
req = blk_queue_find_tag(sdev->request_queue, tag);
|
|
return req ? (struct scsi_cmnd *)req->special : NULL;
|
|
}
|
|
|
|
/* single command, look in space */
|
|
return sdev->current_cmnd;
|
|
}
|
|
|
|
|
|
/**
|
|
* scsi_init_shared_tag_map - create a shared tag map
|
|
* @shost: the host to share the tag map among all devices
|
|
* @depth: the total depth of the map
|
|
*/
|
|
static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
|
|
{
|
|
/*
|
|
* We always have a shared tag map around when using blk-mq.
|
|
*/
|
|
if (shost_use_blk_mq(shost))
|
|
return 0;
|
|
|
|
/*
|
|
* If the shared tag map isn't already initialized, do it now.
|
|
* This saves callers from having to check ->bqt when setting up
|
|
* devices on the shared host (for libata)
|
|
*/
|
|
if (!shost->bqt) {
|
|
shost->bqt = blk_init_tags(depth,
|
|
shost->hostt->tag_alloc_policy);
|
|
if (!shost->bqt)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* scsi_host_find_tag - find the tagged command by host
|
|
* @shost: pointer to scsi_host
|
|
* @tag: tag generated by blk_mq_unique_tag()
|
|
*
|
|
* Notes:
|
|
* Only works with tags allocated by the generic blk layer.
|
|
**/
|
|
static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
|
|
int tag)
|
|
{
|
|
struct request *req;
|
|
|
|
if (tag != SCSI_NO_TAG) {
|
|
if (shost_use_blk_mq(shost))
|
|
return scsi_mq_find_tag(shost, tag);
|
|
req = blk_map_queue_find_tag(shost->bqt, tag);
|
|
return req ? (struct scsi_cmnd *)req->special : NULL;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
#endif /* CONFIG_BLOCK */
|
|
#endif /* _SCSI_SCSI_TCQ_H */
|