forked from luck/tmp_suning_uos_patched
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>
102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
#ifndef _SCSI_SCSI_TCQ_H
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#define _SCSI_SCSI_TCQ_H
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#include <linux/blkdev.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_host.h>
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#define SCSI_NO_TAG (-1) /* identify no tag in use */
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#ifdef CONFIG_BLOCK
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static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
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int unique_tag)
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{
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u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
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struct request *req = NULL;
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if (hwq < shost->tag_set.nr_hw_queues)
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req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
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blk_mq_unique_tag_to_tag(unique_tag));
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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/**
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* scsi_find_tag - find a tagged command by device
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* @SDpnt: pointer to the ScSI device
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* @tag: tag generated by blk_mq_unique_tag()
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*
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* Notes:
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* Only works with tags allocated by the generic blk layer.
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**/
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static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
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{
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struct request *req;
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if (tag != SCSI_NO_TAG) {
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if (shost_use_blk_mq(sdev->host))
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return scsi_mq_find_tag(sdev->host, tag);
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req = blk_queue_find_tag(sdev->request_queue, tag);
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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/* single command, look in space */
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return sdev->current_cmnd;
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}
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/**
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* scsi_init_shared_tag_map - create a shared tag map
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* @shost: the host to share the tag map among all devices
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* @depth: the total depth of the map
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*/
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static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
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{
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/*
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* We always have a shared tag map around when using blk-mq.
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*/
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if (shost_use_blk_mq(shost))
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return 0;
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/*
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* If the shared tag map isn't already initialized, do it now.
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* This saves callers from having to check ->bqt when setting up
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* devices on the shared host (for libata)
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*/
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if (!shost->bqt) {
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shost->bqt = blk_init_tags(depth,
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shost->hostt->tag_alloc_policy);
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if (!shost->bqt)
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return -ENOMEM;
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}
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return 0;
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}
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/**
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* scsi_host_find_tag - find the tagged command by host
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* @shost: pointer to scsi_host
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* @tag: tag generated by blk_mq_unique_tag()
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*
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* Notes:
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* Only works with tags allocated by the generic blk layer.
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**/
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static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
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int tag)
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{
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struct request *req;
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if (tag != SCSI_NO_TAG) {
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if (shost_use_blk_mq(shost))
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return scsi_mq_find_tag(shost, tag);
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req = blk_map_queue_find_tag(shost->bqt, tag);
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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return NULL;
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}
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#endif /* CONFIG_BLOCK */
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#endif /* _SCSI_SCSI_TCQ_H */
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