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 MSG_SIMPLE_TAG  0x20
  10 #define MSG_HEAD_TAG    0x21
  11 #define MSG_ORDERED_TAG 0x22
  12 #define MSG_ACA_TAG     0x24    /* unsupported */
  13
  14 #define SCSI_NO_TAG     (-1)    /* identify no tag in use */
  15
  16
  17 #ifdef CONFIG_BLOCK
  18
  19 int scsi_change_queue_type(struct scsi_device *sdev, int tag_type);
  20
  21 /**
  22  * scsi_get_tag_type - get the type of tag the device supports
  23  * @sdev:       the scsi device
  24  */
  25 static inline int scsi_get_tag_type(struct scsi_device *sdev)
  26 {
  27         if (!sdev->tagged_supported)
  28                 return 0;
  29         if (sdev->simple_tags)
  30                 return MSG_SIMPLE_TAG;
  31         return 0;
  32 }
  33
  34 static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
  35 {
  36         switch (tag) {
  37         case MSG_ORDERED_TAG:
  38         case MSG_SIMPLE_TAG:
  39                 sdev->simple_tags = 1;
  40                 break;
  41         case 0:
  42                 /* fall through */
  43         default:
  44                 sdev->simple_tags = 0;
  45                 break;
  46         }
  47 }
  48 /**
  49  * scsi_activate_tcq - turn on tag command queueing
  50  * @SDpnt:      device to turn on TCQ for
  51  * @depth:      queue depth
  52  *
  53  * Notes:
  54  *      Eventually, I hope depth would be the maximum depth
  55  *      the device could cope with and the real queue depth
  56  *      would be adjustable from 0 to depth.
  57  **/
  58 static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
  59 {
  60         if (!sdev->tagged_supported)
  61                 return;
  62
  63         if (shost_use_blk_mq(sdev->host))
  64                 queue_flag_set_unlocked(QUEUE_FLAG_QUEUED, sdev->request_queue);
  65         else if (!blk_queue_tagged(sdev->request_queue))
  66                 blk_queue_init_tags(sdev->request_queue, depth,
  67                                     sdev->host->bqt);
  68
  69         scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
  70 }
  71
  72 /**
  73  * scsi_deactivate_tcq - turn off tag command queueing
  74  * @SDpnt:      device to turn off TCQ for
  75  **/
  76 static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
  77 {
  78         if (blk_queue_tagged(sdev->request_queue))
  79                 blk_queue_free_tags(sdev->request_queue);
  80         scsi_adjust_queue_depth(sdev, 0, depth);
  81 }
  82
  83 /**
  84  * scsi_populate_tag_msg - place a tag message in a buffer
  85  * @SCpnt:      pointer to the Scsi_Cmnd for the tag
  86  * @msg:        pointer to the area to place the tag
  87  *
  88  * Notes:
  89  *      designed to create the correct type of tag message for the
  90  *      particular request.  Returns the size of the tag message.
  91  *      May return 0 if TCQ is disabled for this device.
  92  **/
  93 static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
  94 {
  95         if (cmd->flags & SCMD_TAGGED) {
  96                 *msg++ = MSG_SIMPLE_TAG;
  97                 *msg++ = cmd->request->tag;
  98                 return 2;
  99         }
 100
 101         return 0;
 102 }
 103
 104 static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
 105                                                  int unique_tag)
 106 {
 107         u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
 108         struct request *req = NULL;
 109
 110         if (hwq < shost->tag_set.nr_hw_queues)
 111                 req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
 112                                        blk_mq_unique_tag_to_tag(unique_tag));
 113         return req ? (struct scsi_cmnd *)req->special : NULL;
 114 }
 115
 116 /**
 117  * scsi_find_tag - find a tagged command by device
 118  * @SDpnt:      pointer to the ScSI device
 119  * @tag:        tag generated by blk_mq_unique_tag()
 120  *
 121  * Notes:
 122  *      Only works with tags allocated by the generic blk layer.
 123  **/
 124 static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
 125 {
 126         struct request *req;
 127
 128         if (tag != SCSI_NO_TAG) {
 129                 if (shost_use_blk_mq(sdev->host))
 130                         return scsi_mq_find_tag(sdev->host, tag);
 131
 132                 req = blk_queue_find_tag(sdev->request_queue, tag);
 133                 return req ? (struct scsi_cmnd *)req->special : NULL;
 134         }
 135
 136         /* single command, look in space */
 137         return sdev->current_cmnd;
 138 }
 139
 140
 141 /**
 142  * scsi_init_shared_tag_map - create a shared tag map
 143  * @shost:      the host to share the tag map among all devices
 144  * @depth:      the total depth of the map
 145  */
 146 static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
 147 {
 148         /*
 149          * We always have a shared tag map around when using blk-mq.
 150          */
 151         if (shost_use_blk_mq(shost))
 152                 return 0;
 153
 154         /*
 155          * If the shared tag map isn't already initialized, do it now.
 156          * This saves callers from having to check ->bqt when setting up
 157          * devices on the shared host (for libata)
 158          */
 159         if (!shost->bqt) {
 160                 shost->bqt = blk_init_tags(depth);
 161                 if (!shost->bqt)
 162                         return -ENOMEM;
 163         }
 164
 165         return 0;
 166 }
 167
 168 /**
 169  * scsi_host_find_tag - find the tagged command by host
 170  * @shost:      pointer to scsi_host
 171  * @tag:        tag generated by blk_mq_unique_tag()
 172  *
 173  * Notes:
 174  *      Only works with tags allocated by the generic blk layer.
 175  **/
 176 static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
 177                                                 int tag)
 178 {
 179         struct request *req;
 180
 181         if (tag != SCSI_NO_TAG) {
 182                 if (shost_use_blk_mq(shost))
 183                         return scsi_mq_find_tag(shost, tag);
 184                 req = blk_map_queue_find_tag(shost->bqt, tag);
 185                 return req ? (struct scsi_cmnd *)req->special : NULL;
 186         }
 187         return NULL;
 188 }
 189
 190 #endif /* CONFIG_BLOCK */
 191 #endif /* _SCSI_SCSI_TCQ_H */