aboutsummaryrefslogtreecommitdiffstats
path: root/include/scsi/scsi_tcq.h
blob: 032df74b66d7f36e57ce0aab110e88a41e7bb47e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
#ifndef _SCSI_SCSI_TCQ_H
#define _SCSI_SCSI_TCQ_H

#include <linux/blkdev.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#define MSG_SIMPLE_TAG	0x20
#define MSG_HEAD_TAG	0x21
#define MSG_ORDERED_TAG	0x22
#define MSG_ACA_TAG	0x24	/* unsupported */

#define SCSI_NO_TAG	(-1)    /* identify no tag in use */


#ifdef CONFIG_BLOCK

int scsi_change_queue_type(struct scsi_device *sdev, int tag_type);

/**
 * scsi_get_tag_type - get the type of tag the device supports
 * @sdev:	the scsi device
 *
 * Notes:
 *	If the drive only supports simple tags, returns MSG_SIMPLE_TAG
 *	if it supports all tag types, returns MSG_ORDERED_TAG.
 */
static inline int scsi_get_tag_type(struct scsi_device *sdev)
{
	if (!sdev->tagged_supported)
		return 0;
	if (sdev->ordered_tags)
		return MSG_ORDERED_TAG;
	if (sdev->simple_tags)
		return MSG_SIMPLE_TAG;
	return 0;
}

static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag)
{
	switch (tag) {
	case MSG_ORDERED_TAG:
		sdev->ordered_tags = 1;
		/* fall through */
	case MSG_SIMPLE_TAG:
		sdev->simple_tags = 1;
		break;
	case 0:
		/* fall through */
	default:
		sdev->ordered_tags = 0;
		sdev->simple_tags = 0;
		break;
	}
}
/**
 * scsi_activate_tcq - turn on tag command queueing
 * @SDpnt:	device to turn on TCQ for
 * @depth:	queue depth
 *
 * Notes:
 *	Eventually, I hope depth would be the maximum depth
 *	the device could cope with and the real queue depth
 *	would be adjustable from 0 to depth.
 **/
static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth)
{
	if (!sdev->tagged_supported)
		return;

	if (shost_use_blk_mq(sdev->host))
		queue_flag_set_unlocked(QUEUE_FLAG_QUEUED, sdev->request_queue);
	else if (!blk_queue_tagged(sdev->request_queue))
		blk_queue_init_tags(sdev->request_queue, depth,
				    sdev->host->bqt);

	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
}

/**
 * scsi_deactivate_tcq - turn off tag command queueing
 * @SDpnt:	device to turn off TCQ for
 **/
static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
{
	if (blk_queue_tagged(sdev->request_queue))
		blk_queue_free_tags(sdev->request_queue);
	scsi_adjust_queue_depth(sdev, 0, depth);
}

/**
 * scsi_populate_tag_msg - place a tag message in a buffer
 * @SCpnt:	pointer to the Scsi_Cmnd for the tag
 * @msg:	pointer to the area to place the tag
 *
 * Notes:
 *	designed to create the correct type of tag message for the 
 *	particular request.  Returns the size of the tag message.
 *	May return 0 if TCQ is disabled for this device.
 **/
static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
{
        if (cmd->flags & SCMD_TAGGED) {
		*msg++ = MSG_SIMPLE_TAG;
        	*msg++ = cmd->request->tag;
        	return 2;
	}

	return 0;
}

static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
						 int unique_tag)
{
	u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
	struct request *req = NULL;

	if (hwq < shost->tag_set.nr_hw_queues)
		req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
				       blk_mq_unique_tag_to_tag(unique_tag));
	return req ? (struct scsi_cmnd *)req->special : NULL;
}

/**
 * scsi_find_tag - find a tagged command by device
 * @SDpnt:	pointer to the ScSI device
 * @tag:	tag generated by blk_mq_unique_tag()
 *
 * Notes:
 *	Only works with tags allocated by the generic blk layer.
 **/
static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
{
        struct request *req;

        if (tag != SCSI_NO_TAG) {
		if (shost_use_blk_mq(sdev->host))
			return scsi_mq_find_tag(sdev->host, tag);

		req = blk_queue_find_tag(sdev->request_queue, tag);
	        return req ? (struct scsi_cmnd *)req->special : NULL;
	}

	/* single command, look in space */
	return sdev->current_cmnd;
}


/**
 * scsi_init_shared_tag_map - create a shared tag map
 * @shost:	the host to share the tag map among all devices
 * @depth:	the total depth of the map
 */
static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
{
	/*
	 * We always have a shared tag map around when using blk-mq.
	 */
	if (shost_use_blk_mq(shost))
		return 0;

	/*
	 * If the shared tag map isn't already initialized, do it now.
	 * This saves callers from having to check ->bqt when setting up
	 * devices on the shared host (for libata)
	 */
	if (!shost->bqt) {
		shost->bqt = blk_init_tags(depth);
		if (!shost->bqt)
			return -ENOMEM;
	}

	return 0;
}

/**
 * scsi_host_find_tag - find the tagged command by host
 * @shost:	pointer to scsi_host
 * @tag:	tag generated by blk_mq_unique_tag()
 *
 * Notes:
 *	Only works with tags allocated by the generic blk layer.
 **/
static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
						int tag)
{
	struct request *req;

	if (tag != SCSI_NO_TAG) {
		if (shost_use_blk_mq(shost))
			return scsi_mq_find_tag(shost, tag);
		req = blk_map_queue_find_tag(shost->bqt, tag);
		return req ? (struct scsi_cmnd *)req->special : NULL;
	}
	return NULL;
}

#endif /* CONFIG_BLOCK */
#endif /* _SCSI_SCSI_TCQ_H */

Privacy Policy