Line data Source code
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 2 : if (!sdev->tagged_supported)
29 1 : return 0;
30 2 : if (sdev->ordered_tags)
31 1 : return MSG_ORDERED_TAG;
32 2 : if (sdev->simple_tags)
33 1 : return MSG_SIMPLE_TAG;
34 1 : 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 */
|