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1 | /* |
2 | * BSG helper library |
3 | * |
4 | * Copyright (C) 2008 James Smart, Emulex Corporation |
5 | * Copyright (C) 2011 Red Hat, Inc. All rights reserved. |
6 | * Copyright (C) 2011 Mike Christie |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License as published by |
10 | * the Free Software Foundation; either version 2 of the License, or |
11 | * (at your option) any later version. |
12 | * |
13 | * This program is distributed in the hope that it will be useful, |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | * GNU General Public License for more details. |
17 | * |
18 | * You should have received a copy of the GNU General Public License |
19 | * along with this program; if not, write to the Free Software |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
21 | * |
22 | */ |
23 | #include <linux/slab.h> |
24 | #include <linux/blkdev.h> |
25 | #include <linux/delay.h> |
26 | #include <linux/scatterlist.h> |
27 | #include <linux/bsg-lib.h> |
28 | #include <linux/export.h> |
29 | #include <scsi/scsi_cmnd.h> |
30 | |
31 | /** |
32 | * bsg_destroy_job - routine to teardown/delete a bsg job |
33 | * @job: bsg_job that is to be torn down |
34 | */ |
35 | static void bsg_destroy_job(struct bsg_job *job) |
36 | { |
37 | put_device(job->dev); /* release reference for the request */ |
38 | |
39 | kfree(job->request_payload.sg_list); |
40 | kfree(job->reply_payload.sg_list); |
41 | kfree(job); |
42 | } |
43 | |
44 | /** |
45 | * bsg_job_done - completion routine for bsg requests |
46 | * @job: bsg_job that is complete |
47 | * @result: job reply result |
48 | * @reply_payload_rcv_len: length of payload recvd |
49 | * |
50 | * The LLD should call this when the bsg job has completed. |
51 | */ |
52 | void bsg_job_done(struct bsg_job *job, int result, |
53 | unsigned int reply_payload_rcv_len) |
54 | { |
55 | struct request *req = job->req; |
56 | struct request *rsp = req->next_rq; |
57 | int err; |
58 | |
59 | err = job->req->errors = result; |
60 | if (err < 0) |
61 | /* we're only returning the result field in the reply */ |
62 | job->req->sense_len = sizeof(u32); |
63 | else |
64 | job->req->sense_len = job->reply_len; |
65 | /* we assume all request payload was transferred, residual == 0 */ |
66 | req->resid_len = 0; |
67 | |
68 | if (rsp) { |
69 | WARN_ON(reply_payload_rcv_len > rsp->resid_len); |
70 | |
71 | /* set reply (bidi) residual */ |
72 | rsp->resid_len -= min(reply_payload_rcv_len, rsp->resid_len); |
73 | } |
74 | blk_complete_request(req); |
75 | } |
76 | EXPORT_SYMBOL_GPL(bsg_job_done); |
77 | |
78 | /** |
79 | * bsg_softirq_done - softirq done routine for destroying the bsg requests |
80 | * @rq: BSG request that holds the job to be destroyed |
81 | */ |
82 | static void bsg_softirq_done(struct request *rq) |
83 | { |
84 | struct bsg_job *job = rq->special; |
85 | |
86 | blk_end_request_all(rq, rq->errors); |
87 | bsg_destroy_job(job); |
88 | } |
89 | |
90 | static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) |
91 | { |
92 | size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); |
93 | |
94 | BUG_ON(!req->nr_phys_segments); |
95 | |
96 | buf->sg_list = kzalloc(sz, GFP_KERNEL); |
97 | if (!buf->sg_list) |
98 | return -ENOMEM; |
99 | sg_init_table(buf->sg_list, req->nr_phys_segments); |
100 | buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); |
101 | buf->payload_len = blk_rq_bytes(req); |
102 | return 0; |
103 | } |
104 | |
105 | /** |
106 | * bsg_create_job - create the bsg_job structure for the bsg request |
107 | * @dev: device that is being sent the bsg request |
108 | * @req: BSG request that needs a job structure |
109 | */ |
110 | static int bsg_create_job(struct device *dev, struct request *req) |
111 | { |
112 | struct request *rsp = req->next_rq; |
113 | struct request_queue *q = req->q; |
114 | struct bsg_job *job; |
115 | int ret; |
116 | |
117 | BUG_ON(req->special); |
118 | |
119 | job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL); |
120 | if (!job) |
121 | return -ENOMEM; |
122 | |
123 | req->special = job; |
124 | job->req = req; |
125 | if (q->bsg_job_size) |
126 | job->dd_data = (void *)&job[1]; |
127 | job->request = req->cmd; |
128 | job->request_len = req->cmd_len; |
129 | job->reply = req->sense; |
130 | job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer |
131 | * allocated */ |
132 | if (req->bio) { |
133 | ret = bsg_map_buffer(&job->request_payload, req); |
134 | if (ret) |
135 | goto failjob_rls_job; |
136 | } |
137 | if (rsp && rsp->bio) { |
138 | ret = bsg_map_buffer(&job->reply_payload, rsp); |
139 | if (ret) |
140 | goto failjob_rls_rqst_payload; |
141 | } |
142 | job->dev = dev; |
143 | /* take a reference for the request */ |
144 | get_device(job->dev); |
145 | return 0; |
146 | |
147 | failjob_rls_rqst_payload: |
148 | kfree(job->request_payload.sg_list); |
149 | failjob_rls_job: |
150 | kfree(job); |
151 | return -ENOMEM; |
152 | } |
153 | |
154 | /* |
155 | * bsg_goose_queue - restart queue in case it was stopped |
156 | * @q: request q to be restarted |
157 | */ |
158 | void bsg_goose_queue(struct request_queue *q) |
159 | { |
160 | if (!q) |
161 | return; |
162 | |
163 | blk_run_queue_async(q); |
164 | } |
165 | EXPORT_SYMBOL_GPL(bsg_goose_queue); |
166 | |
167 | /** |
168 | * bsg_request_fn - generic handler for bsg requests |
169 | * @q: request queue to manage |
170 | * |
171 | * On error the create_bsg_job function should return a -Exyz error value |
172 | * that will be set to the req->errors. |
173 | * |
174 | * Drivers/subsys should pass this to the queue init function. |
175 | */ |
176 | void bsg_request_fn(struct request_queue *q) |
177 | { |
178 | struct device *dev = q->queuedata; |
179 | struct request *req; |
180 | struct bsg_job *job; |
181 | int ret; |
182 | |
183 | if (!get_device(dev)) |
184 | return; |
185 | |
186 | while (1) { |
187 | req = blk_fetch_request(q); |
188 | if (!req) |
189 | break; |
190 | spin_unlock_irq(q->queue_lock); |
191 | |
192 | ret = bsg_create_job(dev, req); |
193 | if (ret) { |
194 | req->errors = ret; |
195 | blk_end_request_all(req, ret); |
196 | spin_lock_irq(q->queue_lock); |
197 | continue; |
198 | } |
199 | |
200 | job = req->special; |
201 | ret = q->bsg_job_fn(job); |
202 | spin_lock_irq(q->queue_lock); |
203 | if (ret) |
204 | break; |
205 | } |
206 | |
207 | spin_unlock_irq(q->queue_lock); |
208 | put_device(dev); |
209 | spin_lock_irq(q->queue_lock); |
210 | } |
211 | EXPORT_SYMBOL_GPL(bsg_request_fn); |
212 | |
213 | /** |
214 | * bsg_setup_queue - Create and add the bsg hooks so we can receive requests |
215 | * @dev: device to attach bsg device to |
216 | * @q: request queue setup by caller |
217 | * @name: device to give bsg device |
218 | * @job_fn: bsg job handler |
219 | * @dd_job_size: size of LLD data needed for each job |
220 | * |
221 | * The caller should have setup the reuqest queue with bsg_request_fn |
222 | * as the request_fn. |
223 | */ |
224 | int bsg_setup_queue(struct device *dev, struct request_queue *q, |
225 | char *name, bsg_job_fn *job_fn, int dd_job_size) |
226 | { |
227 | int ret; |
228 | |
229 | q->queuedata = dev; |
230 | q->bsg_job_size = dd_job_size; |
231 | q->bsg_job_fn = job_fn; |
232 | queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); |
233 | blk_queue_softirq_done(q, bsg_softirq_done); |
234 | blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); |
235 | |
236 | ret = bsg_register_queue(q, dev, name, NULL); |
237 | if (ret) { |
238 | printk(KERN_ERR "%s: bsg interface failed to " |
239 | "initialize - register queue\n", dev->kobj.name); |
240 | return ret; |
241 | } |
242 | |
243 | return 0; |
244 | } |
245 | EXPORT_SYMBOL_GPL(bsg_setup_queue); |
246 |
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