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