aboutsummaryrefslogtreecommitdiffstats
path: root/block/bsg-lib.c
blob: cd15f9dbb1474ad5aeb7b387420f9a6dbd021f95 (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
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
/*
 *  BSG helper library
 *
 *  Copyright (C) 2008   James Smart, Emulex Corporation
 *  Copyright (C) 2011   Red Hat, Inc.  All rights reserved.
 *  Copyright (C) 2011   Mike Christie
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/scatterlist.h>
#include <linux/bsg-lib.h>
#include <linux/export.h>
#include <scsi/scsi_cmnd.h>

/**
 * bsg_destroy_job - routine to teardown/delete a bsg job
 * @job: bsg_job that is to be torn down
 */
static void bsg_destroy_job(struct kref *kref)
{
	struct bsg_job *job = container_of(kref, struct bsg_job, kref);
	struct request *rq = job->req;

	blk_end_request_all(rq, rq->errors);

	put_device(job->dev);	/* release reference for the request */

	kfree(job->request_payload.sg_list);
	kfree(job->reply_payload.sg_list);
	kfree(job);
}

void bsg_job_put(struct bsg_job *job)
{
	kref_put(&job->kref, bsg_destroy_job);
}
EXPORT_SYMBOL_GPL(bsg_job_put);

int bsg_job_get(struct bsg_job *job)
{
	return kref_get_unless_zero(&job->kref);
}
EXPORT_SYMBOL_GPL(bsg_job_get);

/**
 * bsg_job_done - completion routine for bsg requests
 * @job: bsg_job that is complete
 * @result: job reply result
 * @reply_payload_rcv_len: length of payload recvd
 *
 * The LLD should call this when the bsg job has completed.
 */
void bsg_job_done(struct bsg_job *job, int result,
		  unsigned int reply_payload_rcv_len)
{
	struct request *req = job->req;
	struct request *rsp = req->next_rq;
	struct scsi_request *rq = scsi_req(req);
	int err;

	err = job->req->errors = result;
	if (err < 0)
		/* we're only returning the result field in the reply */
		rq->sense_len = sizeof(u32);
	else
		rq->sense_len = job->reply_len;
	/* we assume all request payload was transferred, residual == 0 */
	rq->resid_len = 0;

	if (rsp) {
		WARN_ON(reply_payload_rcv_len > scsi_req(rsp)->resid_len);

		/* set reply (bidi) residual */
		scsi_req(rsp)->resid_len -=
			min(reply_payload_rcv_len, scsi_req(rsp)->resid_len);
	}
	blk_complete_request(req);
}
EXPORT_SYMBOL_GPL(bsg_job_done);

/**
 * bsg_softirq_done - softirq done routine for destroying the bsg requests
 * @rq: BSG request that holds the job to be destroyed
 */
static void bsg_softirq_done(struct request *rq)
{
	struct bsg_job *job = rq->special;

	bsg_job_put(job);
}

static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
{
	size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);

	BUG_ON(!req->nr_phys_segments);

	buf->sg_list = kzalloc(sz, GFP_KERNEL);
	if (!buf->sg_list)
		return -ENOMEM;
	sg_init_table(buf->sg_list, req->nr_phys_segments);
	scsi_req(req)->resid_len = blk_rq_bytes(req);
	buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
	buf->payload_len = blk_rq_bytes(req);
	return 0;
}

/**
 * bsg_create_job - create the bsg_job structure for the bsg request
 * @dev: device that is being sent the bsg request
 * @req: BSG request that needs a job structure
 */
static int bsg_create_job(struct device *dev, struct request *req)
{
	struct request *rsp = req->next_rq;
	struct request_queue *q = req->q;
	struct scsi_request *rq = scsi_req(req);
	struct bsg_job *job;
	int ret;

	BUG_ON(req->special);

	job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL);
	if (!job)
		return -ENOMEM;

	req->special = job;
	job->req = req;
	if (q->bsg_job_size)
		job->dd_data = (void *)&job[1];
	job->request = rq->cmd;
	job->request_len = rq->cmd_len;
	job->reply = rq->sense;
	job->reply_len = SCSI_SENSE_BUFFERSIZE;	/* Size of sense buffer
						 * allocated */
	if (req->bio) {
		ret = bsg_map_buffer(&job->request_payload, req);
		if (ret)
			goto failjob_rls_job;
	}
	if (rsp && rsp->bio) {
		ret = bsg_map_buffer(&job->reply_payload, rsp);
		if (ret)
			goto failjob_rls_rqst_payload;
	}
	job->dev = dev;
	/* take a reference for the request */
	get_device(job->dev);
	kref_init(&job->kref);
	return 0;

failjob_rls_rqst_payload:
	kfree(job->request_payload.sg_list);
failjob_rls_job:
	kfree(job);
	return -ENOMEM;
}

/**
 * bsg_request_fn - generic handler for bsg requests
 * @q: request queue to manage
 *
 * On error the create_bsg_job function should return a -Exyz error value
 * that will be set to the req->errors.
 *
 * Drivers/subsys should pass this to the queue init function.
 */
static void bsg_request_fn(struct request_queue *q)
	__releases(q->queue_lock)
	__acquires(q->queue_lock)
{
	struct device *dev = q->queuedata;
	struct request *req;
	struct bsg_job *job;
	int ret;

	if (!get_device(dev))
		return;

	while (1) {
		req = blk_fetch_request(q);
		if (!req)
			break;
		spin_unlock_irq(q->queue_lock);

		ret = bsg_create_job(dev, req);
		if (ret) {
			req->errors = ret;
			blk_end_request_all(req, ret);
			spin_lock_irq(q->queue_lock);
			continue;
		}

		job = req->special;
		ret = q->bsg_job_fn(job);
		spin_lock_irq(q->queue_lock);
		if (ret)
			break;
	}

	spin_unlock_irq(q->queue_lock);
	put_device(dev);
	spin_lock_irq(q->queue_lock);
}

/**
 * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
 * @dev: device to attach bsg device to
 * @name: device to give bsg device
 * @job_fn: bsg job handler
 * @dd_job_size: size of LLD data needed for each job
 */
struct request_queue *bsg_setup_queue(struct device *dev, char *name,
		bsg_job_fn *job_fn, int dd_job_size)
{
	struct request_queue *q;
	int ret;

	q = blk_alloc_queue(GFP_KERNEL);
	if (!q)
		return ERR_PTR(-ENOMEM);
	q->cmd_size = sizeof(struct scsi_request);
	q->request_fn = bsg_request_fn;

	ret = blk_init_allocated_queue(q);
	if (ret)
		goto out_cleanup_queue;

	q->queuedata = dev;
	q->bsg_job_size = dd_job_size;
	q->bsg_job_fn = job_fn;
	queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
	blk_queue_softirq_done(q, bsg_softirq_done);
	blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);

	ret = bsg_register_queue(q, dev, name, NULL);
	if (ret) {
		printk(KERN_ERR "%s: bsg interface failed to "
		       "initialize - register queue\n", dev->kobj.name);
		goto out_cleanup_queue;
	}

	return q;
out_cleanup_queue:
	blk_cleanup_queue(q);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(bsg_setup_queue);

Privacy Policy