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scsi_tcq.h
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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 
27 static inline int scsi_get_tag_type(struct scsi_device *sdev)
28 {
29  if (!sdev->tagged_supported)
30  return 0;
31  if (sdev->ordered_tags)
32  return MSG_ORDERED_TAG;
33  if (sdev->simple_tags)
34  return MSG_SIMPLE_TAG;
35  return 0;
36 }
37 
38 static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
39 {
40  switch (tag) {
41  case MSG_ORDERED_TAG:
42  sdev->ordered_tags = 1;
43  /* fall through */
44  case MSG_SIMPLE_TAG:
45  sdev->simple_tags = 1;
46  break;
47  case 0:
48  /* fall through */
49  default:
50  sdev->ordered_tags = 0;
51  sdev->simple_tags = 0;
52  break;
53  }
54 }
65 static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
66 {
67  if (!sdev->tagged_supported)
68  return;
69 
70  if (!blk_queue_tagged(sdev->request_queue))
72  sdev->host->bqt);
73 
74  scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
75 }
76 
81 static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
82 {
83  if (blk_queue_tagged(sdev->request_queue))
85  scsi_adjust_queue_depth(sdev, 0, depth);
86 }
87 
98 static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
99 {
100  struct request *req = cmd->request;
101 
102  if (blk_rq_tagged(req)) {
103  *msg++ = MSG_SIMPLE_TAG;
104  *msg++ = req->tag;
105  return 2;
106  }
107 
108  return 0;
109 }
110 
119 static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
120 {
121 
122  struct request *req;
123 
124  if (tag != SCSI_NO_TAG) {
125  req = blk_queue_find_tag(sdev->request_queue, tag);
126  return req ? (struct scsi_cmnd *)req->special : NULL;
127  }
128 
129  /* single command, look in space */
130  return sdev->current_cmnd;
131 }
132 
138 static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
139 {
140  /*
141  * If the shared tag map isn't already initialized, do it now.
142  * This saves callers from having to check ->bqt when setting up
143  * devices on the shared host (for libata)
144  */
145  if (!shost->bqt) {
146  shost->bqt = blk_init_tags(depth);
147  if (!shost->bqt)
148  return -ENOMEM;
149  }
150 
151  return 0;
152 }
153 
162 static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
163  int tag)
164 {
165  struct request *req;
166 
167  if (tag != SCSI_NO_TAG) {
168  req = blk_map_queue_find_tag(shost->bqt, tag);
169  return req ? (struct scsi_cmnd *)req->special : NULL;
170  }
171  return NULL;
172 }
173 
174 #endif /* CONFIG_BLOCK */
175 #endif /* _SCSI_SCSI_TCQ_H */