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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> | |
7 | ||
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 | ||
17 | /** | |
18 | * scsi_get_tag_type - get the type of tag the device supports | |
19 | * @sdev: the scsi device | |
20 | * | |
21 | * Notes: | |
22 | * If the drive only supports simple tags, returns MSG_SIMPLE_TAG | |
23 | * if it supports all tag types, returns MSG_ORDERED_TAG. | |
24 | */ | |
25 | static inline int scsi_get_tag_type(struct scsi_device *sdev) | |
26 | { | |
27 | if (!sdev->tagged_supported) | |
28 | return 0; | |
29 | if (sdev->ordered_tags) | |
30 | return MSG_ORDERED_TAG; | |
31 | if (sdev->simple_tags) | |
32 | return MSG_SIMPLE_TAG; | |
33 | return 0; | |
34 | } | |
35 | ||
36 | static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag) | |
37 | { | |
38 | switch (tag) { | |
39 | case MSG_ORDERED_TAG: | |
40 | sdev->ordered_tags = 1; | |
41 | /* fall through */ | |
42 | case MSG_SIMPLE_TAG: | |
43 | sdev->simple_tags = 1; | |
44 | break; | |
45 | case 0: | |
46 | /* fall through */ | |
47 | default: | |
48 | sdev->ordered_tags = 0; | |
49 | sdev->simple_tags = 0; | |
50 | break; | |
51 | } | |
52 | } | |
53 | /** | |
54 | * scsi_activate_tcq - turn on tag command queueing | |
55 | * @SDpnt: device to turn on TCQ for | |
56 | * @depth: queue depth | |
57 | * | |
58 | * Notes: | |
59 | * Eventually, I hope depth would be the maximum depth | |
60 | * the device could cope with and the real queue depth | |
61 | * would be adjustable from 0 to depth. | |
62 | **/ | |
63 | static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth) | |
64 | { | |
65 | if (!sdev->tagged_supported) | |
66 | return; | |
67 | ||
68 | if (!blk_queue_tagged(sdev->request_queue)) | |
69 | blk_queue_init_tags(sdev->request_queue, depth, NULL); | |
70 | ||
71 | scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth); | |
72 | } | |
73 | ||
74 | /** | |
75 | * scsi_deactivate_tcq - turn off tag command queueing | |
76 | * @SDpnt: device to turn off TCQ for | |
77 | **/ | |
78 | static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth) | |
79 | { | |
80 | if (blk_queue_tagged(sdev->request_queue)) | |
81 | blk_queue_free_tags(sdev->request_queue); | |
82 | scsi_adjust_queue_depth(sdev, 0, depth); | |
83 | } | |
84 | ||
85 | /** | |
86 | * scsi_populate_tag_msg - place a tag message in a buffer | |
87 | * @SCpnt: pointer to the Scsi_Cmnd for the tag | |
88 | * @msg: pointer to the area to place the tag | |
89 | * | |
90 | * Notes: | |
91 | * designed to create the correct type of tag message for the | |
92 | * particular request. Returns the size of the tag message. | |
93 | * May return 0 if TCQ is disabled for this device. | |
94 | **/ | |
95 | static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg) | |
96 | { | |
97 | struct request *req = cmd->request; | |
98 | struct scsi_device *sdev = cmd->device; | |
99 | ||
100 | if (blk_rq_tagged(req)) { | |
101 | if (sdev->ordered_tags && req->flags & REQ_HARDBARRIER) | |
102 | *msg++ = MSG_ORDERED_TAG; | |
103 | else | |
104 | *msg++ = MSG_SIMPLE_TAG; | |
105 | *msg++ = req->tag; | |
106 | return 2; | |
107 | } | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
112 | /** | |
113 | * scsi_find_tag - find a tagged command by device | |
114 | * @SDpnt: pointer to the ScSI device | |
115 | * @tag: the tag number | |
116 | * | |
117 | * Notes: | |
118 | * Only works with tags allocated by the generic blk layer. | |
119 | **/ | |
120 | static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag) | |
121 | { | |
122 | ||
123 | struct request *req; | |
124 | ||
125 | if (tag != SCSI_NO_TAG) { | |
126 | req = blk_queue_find_tag(sdev->request_queue, tag); | |
127 | return req ? (struct scsi_cmnd *)req->special : NULL; | |
128 | } | |
129 | ||
130 | /* single command, look in space */ | |
131 | return sdev->current_cmnd; | |
132 | } | |
133 | ||
134 | #endif /* _SCSI_SCSI_TCQ_H */ |