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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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>
James Bottomley86e33a22006-08-30 09:45:51 -04007#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#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
David Howells93614012006-09-30 20:45:40 +020016#ifdef CONFIG_BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
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 */
26static 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
37static 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 **/
64static 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))
James Bottomley86e33a22006-08-30 09:45:51 -040070 blk_queue_init_tags(sdev->request_queue, depth,
71 sdev->host->bqt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
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 **/
80static 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 **/
97static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
98{
99 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
101 if (blk_rq_tagged(req)) {
Tejun Heo9cbbdca2010-09-03 11:56:16 +0200102 *msg++ = MSG_SIMPLE_TAG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 *msg++ = req->tag;
104 return 2;
105 }
106
107 return 0;
108}
109
110/**
111 * scsi_find_tag - find a tagged command by device
112 * @SDpnt: pointer to the ScSI device
113 * @tag: the tag number
114 *
115 * Notes:
116 * Only works with tags allocated by the generic blk layer.
117 **/
118static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
119{
120
121 struct request *req;
122
123 if (tag != SCSI_NO_TAG) {
124 req = blk_queue_find_tag(sdev->request_queue, tag);
125 return req ? (struct scsi_cmnd *)req->special : NULL;
126 }
127
128 /* single command, look in space */
129 return sdev->current_cmnd;
130}
131
James Bottomley86e33a22006-08-30 09:45:51 -0400132/**
133 * scsi_init_shared_tag_map - create a shared tag map
134 * @shost: the host to share the tag map among all devices
135 * @depth: the total depth of the map
136 */
James Bottomleydeb81d82006-09-01 09:28:48 -0400137static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
James Bottomley86e33a22006-08-30 09:45:51 -0400138{
Jens Axboe3070f692008-10-27 19:20:59 +0100139 /*
140 * If the shared tag map isn't already initialized, do it now.
141 * This saves callers from having to check ->bqt when setting up
142 * devices on the shared host (for libata)
143 */
144 if (!shost->bqt) {
145 shost->bqt = blk_init_tags(depth);
146 if (!shost->bqt)
147 return -ENOMEM;
148 }
149
150 return 0;
James Bottomley86e33a22006-08-30 09:45:51 -0400151}
152
David C Somayajuluf583f492006-10-04 08:27:25 +0200153/**
154 * scsi_host_find_tag - find the tagged command by host
155 * @shost: pointer to scsi_host
156 * @tag: tag of the scsi_cmnd
157 *
158 * Notes:
159 * Only works with tags allocated by the generic blk layer.
160 **/
161static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
162 int tag)
163{
164 struct request *req;
165
166 if (tag != SCSI_NO_TAG) {
167 req = blk_map_queue_find_tag(shost->bqt, tag);
168 return req ? (struct scsi_cmnd *)req->special : NULL;
169 }
170 return NULL;
171}
172
David Howells93614012006-09-30 20:45:40 +0200173#endif /* CONFIG_BLOCK */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174#endif /* _SCSI_SCSI_TCQ_H */