1 #ifndef _SCSI_SCSI_TCQ_H
2 #define _SCSI_SCSI_TCQ_H
4 #include <linux/blkdev.h>
5 #include <scsi/scsi_cmnd.h>
6 #include <scsi/scsi_device.h>
7 #include <scsi/scsi_host.h>
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 */
14 #define SCSI_NO_TAG (-1) /* identify no tag in use */
20 * scsi_get_tag_type - get the type of tag the device supports
21 * @sdev: the scsi device
24 * If the drive only supports simple tags, returns MSG_SIMPLE_TAG
25 * if it supports all tag types, returns MSG_ORDERED_TAG.
27 static inline int scsi_get_tag_type(struct scsi_device *sdev)
29 if (!sdev->tagged_supported)
31 if (sdev->ordered_tags)
32 return MSG_ORDERED_TAG;
33 if (sdev->simple_tags)
34 return MSG_SIMPLE_TAG;
38 static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
42 sdev->ordered_tags = 1;
45 sdev->simple_tags = 1;
50 sdev->ordered_tags = 0;
51 sdev->simple_tags = 0;
56 * scsi_activate_tcq - turn on tag command queueing
57 * @SDpnt: device to turn on TCQ for
61 * Eventually, I hope depth would be the maximum depth
62 * the device could cope with and the real queue depth
63 * would be adjustable from 0 to depth.
65 static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
67 if (!sdev->tagged_supported)
70 if (!shost_use_blk_mq(sdev->host) &&
71 !blk_queue_tagged(sdev->request_queue))
72 blk_queue_init_tags(sdev->request_queue, depth,
75 scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
79 * scsi_deactivate_tcq - turn off tag command queueing
80 * @SDpnt: device to turn off TCQ for
82 static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
84 if (!shost_use_blk_mq(sdev->host) &&
85 blk_queue_tagged(sdev->request_queue))
86 blk_queue_free_tags(sdev->request_queue);
87 scsi_adjust_queue_depth(sdev, 0, depth);
91 * scsi_populate_tag_msg - place a tag message in a buffer
92 * @SCpnt: pointer to the Scsi_Cmnd for the tag
93 * @msg: pointer to the area to place the tag
96 * designed to create the correct type of tag message for the
97 * particular request. Returns the size of the tag message.
98 * May return 0 if TCQ is disabled for this device.
100 static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
102 struct request *req = cmd->request;
104 if (blk_rq_tagged(req)) {
105 *msg++ = MSG_SIMPLE_TAG;
113 static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
114 unsigned int hw_ctx, int tag)
118 req = blk_mq_tag_to_rq(shost->tag_set.tags[hw_ctx], tag);
119 return req ? (struct scsi_cmnd *)req->special : NULL;
123 * scsi_find_tag - find a tagged command by device
124 * @SDpnt: pointer to the ScSI device
125 * @tag: the tag number
128 * Only works with tags allocated by the generic blk layer.
130 static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
134 if (tag != SCSI_NO_TAG) {
135 if (shost_use_blk_mq(sdev->host))
136 return scsi_mq_find_tag(sdev->host, 0, tag);
138 req = blk_queue_find_tag(sdev->request_queue, tag);
139 return req ? (struct scsi_cmnd *)req->special : NULL;
142 /* single command, look in space */
143 return sdev->current_cmnd;
148 * scsi_init_shared_tag_map - create a shared tag map
149 * @shost: the host to share the tag map among all devices
150 * @depth: the total depth of the map
152 static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
155 * We always have a shared tag map around when using blk-mq.
157 if (shost_use_blk_mq(shost))
161 * If the shared tag map isn't already initialized, do it now.
162 * This saves callers from having to check ->bqt when setting up
163 * devices on the shared host (for libata)
166 shost->bqt = blk_init_tags(depth);
175 * scsi_host_find_tag - find the tagged command by host
176 * @shost: pointer to scsi_host
177 * @tag: tag of the scsi_cmnd
180 * Only works with tags allocated by the generic blk layer.
182 static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
187 if (tag != SCSI_NO_TAG) {
188 if (shost_use_blk_mq(shost))
189 return scsi_mq_find_tag(shost, 0, tag);
190 req = blk_map_queue_find_tag(shost->bqt, tag);
191 return req ? (struct scsi_cmnd *)req->special : NULL;
196 #endif /* CONFIG_BLOCK */
197 #endif /* _SCSI_SCSI_TCQ_H */