include/scsi/scsi_tcq.h

   1 #ifndef _SCSI_SCSI_TCQ_H
   2 #define _SCSI_SCSI_TCQ_H
   3
   4 #include <linux/blkdev.h>
   5 #include <scsi/scsi_cmnd.h>
   6 #include <scsi/scsi_device.h>
   7 #include <scsi/scsi_host.h>
   8
   9 #define SCSI_NO_TAG     (-1)    /* identify no tag in use */
  10
  11
  12 #ifdef CONFIG_BLOCK
  13 static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
  14                                                  int unique_tag)
  15 {
  16         u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
  17         struct request *req = NULL;
  18
  19         if (hwq < shost->tag_set.nr_hw_queues)
  20                 req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
  21                                        blk_mq_unique_tag_to_tag(unique_tag));
  22         return req ? (struct scsi_cmnd *)req->special : NULL;
  23 }
  24
  25 /**
  26  * scsi_find_tag - find a tagged command by device
  27  * @SDpnt:      pointer to the ScSI device
  28  * @tag:        tag generated by blk_mq_unique_tag()
  29  *
  30  * Notes:
  31  *      Only works with tags allocated by the generic blk layer.
  32  **/
  33 static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
  34 {
  35         struct request *req;
  36
  37         if (tag != SCSI_NO_TAG) {
  38                 if (shost_use_blk_mq(sdev->host))
  39                         return scsi_mq_find_tag(sdev->host, tag);
  40
  41                 req = blk_queue_find_tag(sdev->request_queue, tag);
  42                 return req ? (struct scsi_cmnd *)req->special : NULL;
  43         }
  44
  45         /* single command, look in space */
  46         return sdev->current_cmnd;
  47 }
  48
  49
  50 /**
  51  * scsi_init_shared_tag_map - create a shared tag map
  52  * @shost:      the host to share the tag map among all devices
  53  * @depth:      the total depth of the map
  54  */
  55 static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
  56 {
  57         /*
  58          * We always have a shared tag map around when using blk-mq.
  59          */
  60         if (shost_use_blk_mq(shost))
  61                 return 0;
  62
  63         /*
  64          * If the shared tag map isn't already initialized, do it now.
  65          * This saves callers from having to check ->bqt when setting up
  66          * devices on the shared host (for libata)
  67          */
  68         if (!shost->bqt) {
  69                 shost->bqt = blk_init_tags(depth,
  70                         shost->hostt->tag_alloc_policy);
  71                 if (!shost->bqt)
  72                         return -ENOMEM;
  73         }
  74
  75         return 0;
  76 }
  77
  78 /**
  79  * scsi_host_find_tag - find the tagged command by host
  80  * @shost:      pointer to scsi_host
  81  * @tag:        tag generated by blk_mq_unique_tag()
  82  *
  83  * Notes:
  84  *      Only works with tags allocated by the generic blk layer.
  85  **/
  86 static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
  87                                                 int tag)
  88 {
  89         struct request *req;
  90
  91         if (tag != SCSI_NO_TAG) {
  92                 if (shost_use_blk_mq(shost))
  93                         return scsi_mq_find_tag(shost, tag);
  94                 req = blk_map_queue_find_tag(shost->bqt, tag);
  95                 return req ? (struct scsi_cmnd *)req->special : NULL;
  96         }
  97         return NULL;
  98 }
  99
 100 #endif /* CONFIG_BLOCK */
 101 #endif /* _SCSI_SCSI_TCQ_H */