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1da177e4 LT |
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> | |
86e33a29 | 7 | #include <scsi/scsi_host.h> |
1da177e4 LT |
8 | |
9 | ||
10 | #define MSG_SIMPLE_TAG 0x20 | |
11 | #define MSG_HEAD_TAG 0x21 | |
12 | #define MSG_ORDERED_TAG 0x22 | |
13 | ||
14 | #define SCSI_NO_TAG (-1) /* identify no tag in use */ | |
15 | ||
16 | ||
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)) | |
86e33a29 JB |
70 | blk_queue_init_tags(sdev->request_queue, depth, |
71 | sdev->host->bqt); | |
1da177e4 LT |
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->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 | ||
86e33a29 JB |
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 | */ | |
deb81d80 | 141 | static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth) |
86e33a29 JB |
142 | { |
143 | shost->bqt = blk_init_tags(depth); | |
deb81d80 | 144 | return shost->bqt ? 0 : -ENOMEM; |
86e33a29 JB |
145 | } |
146 | ||
1da177e4 | 147 | #endif /* _SCSI_SCSI_TCQ_H */ |