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aa387cc8 MC |
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> | |
6adb1236 | 28 | #include <linux/export.h> |
aa387cc8 MC |
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 | */ | |
bf0f2d38 | 35 | static void bsg_destroy_job(struct kref *kref) |
aa387cc8 | 36 | { |
bf0f2d38 JT |
37 | struct bsg_job *job = container_of(kref, struct bsg_job, kref); |
38 | ||
aa387cc8 MC |
39 | put_device(job->dev); /* release reference for the request */ |
40 | ||
41 | kfree(job->request_payload.sg_list); | |
42 | kfree(job->reply_payload.sg_list); | |
43 | kfree(job); | |
44 | } | |
45 | ||
46 | /** | |
47 | * bsg_job_done - completion routine for bsg requests | |
48 | * @job: bsg_job that is complete | |
49 | * @result: job reply result | |
50 | * @reply_payload_rcv_len: length of payload recvd | |
51 | * | |
52 | * The LLD should call this when the bsg job has completed. | |
53 | */ | |
54 | void bsg_job_done(struct bsg_job *job, int result, | |
55 | unsigned int reply_payload_rcv_len) | |
56 | { | |
57 | struct request *req = job->req; | |
58 | struct request *rsp = req->next_rq; | |
59 | int err; | |
60 | ||
61 | err = job->req->errors = result; | |
62 | if (err < 0) | |
63 | /* we're only returning the result field in the reply */ | |
64 | job->req->sense_len = sizeof(u32); | |
65 | else | |
66 | job->req->sense_len = job->reply_len; | |
67 | /* we assume all request payload was transferred, residual == 0 */ | |
68 | req->resid_len = 0; | |
69 | ||
70 | if (rsp) { | |
71 | WARN_ON(reply_payload_rcv_len > rsp->resid_len); | |
72 | ||
73 | /* set reply (bidi) residual */ | |
74 | rsp->resid_len -= min(reply_payload_rcv_len, rsp->resid_len); | |
75 | } | |
76 | blk_complete_request(req); | |
77 | } | |
78 | EXPORT_SYMBOL_GPL(bsg_job_done); | |
79 | ||
80 | /** | |
81 | * bsg_softirq_done - softirq done routine for destroying the bsg requests | |
82 | * @rq: BSG request that holds the job to be destroyed | |
83 | */ | |
84 | static void bsg_softirq_done(struct request *rq) | |
85 | { | |
86 | struct bsg_job *job = rq->special; | |
87 | ||
88 | blk_end_request_all(rq, rq->errors); | |
bf0f2d38 | 89 | kref_put(&job->kref, bsg_destroy_job); |
aa387cc8 MC |
90 | } |
91 | ||
92 | static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) | |
93 | { | |
94 | size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); | |
95 | ||
96 | BUG_ON(!req->nr_phys_segments); | |
97 | ||
98 | buf->sg_list = kzalloc(sz, GFP_KERNEL); | |
99 | if (!buf->sg_list) | |
100 | return -ENOMEM; | |
101 | sg_init_table(buf->sg_list, req->nr_phys_segments); | |
102 | buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); | |
103 | buf->payload_len = blk_rq_bytes(req); | |
104 | return 0; | |
105 | } | |
106 | ||
107 | /** | |
108 | * bsg_create_job - create the bsg_job structure for the bsg request | |
109 | * @dev: device that is being sent the bsg request | |
110 | * @req: BSG request that needs a job structure | |
111 | */ | |
112 | static int bsg_create_job(struct device *dev, struct request *req) | |
113 | { | |
114 | struct request *rsp = req->next_rq; | |
115 | struct request_queue *q = req->q; | |
116 | struct bsg_job *job; | |
117 | int ret; | |
118 | ||
119 | BUG_ON(req->special); | |
120 | ||
121 | job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL); | |
122 | if (!job) | |
123 | return -ENOMEM; | |
124 | ||
125 | req->special = job; | |
126 | job->req = req; | |
127 | if (q->bsg_job_size) | |
128 | job->dd_data = (void *)&job[1]; | |
129 | job->request = req->cmd; | |
130 | job->request_len = req->cmd_len; | |
131 | job->reply = req->sense; | |
132 | job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer | |
133 | * allocated */ | |
134 | if (req->bio) { | |
135 | ret = bsg_map_buffer(&job->request_payload, req); | |
136 | if (ret) | |
137 | goto failjob_rls_job; | |
138 | } | |
139 | if (rsp && rsp->bio) { | |
140 | ret = bsg_map_buffer(&job->reply_payload, rsp); | |
141 | if (ret) | |
142 | goto failjob_rls_rqst_payload; | |
143 | } | |
144 | job->dev = dev; | |
145 | /* take a reference for the request */ | |
146 | get_device(job->dev); | |
bf0f2d38 | 147 | kref_init(&job->kref); |
aa387cc8 MC |
148 | return 0; |
149 | ||
150 | failjob_rls_rqst_payload: | |
151 | kfree(job->request_payload.sg_list); | |
152 | failjob_rls_job: | |
153 | kfree(job); | |
154 | return -ENOMEM; | |
155 | } | |
156 | ||
aa387cc8 MC |
157 | /** |
158 | * bsg_request_fn - generic handler for bsg requests | |
159 | * @q: request queue to manage | |
160 | * | |
161 | * On error the create_bsg_job function should return a -Exyz error value | |
162 | * that will be set to the req->errors. | |
163 | * | |
164 | * Drivers/subsys should pass this to the queue init function. | |
165 | */ | |
166 | void bsg_request_fn(struct request_queue *q) | |
167 | { | |
168 | struct device *dev = q->queuedata; | |
169 | struct request *req; | |
170 | struct bsg_job *job; | |
171 | int ret; | |
172 | ||
173 | if (!get_device(dev)) | |
174 | return; | |
175 | ||
176 | while (1) { | |
177 | req = blk_fetch_request(q); | |
178 | if (!req) | |
179 | break; | |
180 | spin_unlock_irq(q->queue_lock); | |
181 | ||
182 | ret = bsg_create_job(dev, req); | |
183 | if (ret) { | |
184 | req->errors = ret; | |
185 | blk_end_request_all(req, ret); | |
186 | spin_lock_irq(q->queue_lock); | |
187 | continue; | |
188 | } | |
189 | ||
190 | job = req->special; | |
191 | ret = q->bsg_job_fn(job); | |
192 | spin_lock_irq(q->queue_lock); | |
193 | if (ret) | |
194 | break; | |
195 | } | |
196 | ||
197 | spin_unlock_irq(q->queue_lock); | |
198 | put_device(dev); | |
199 | spin_lock_irq(q->queue_lock); | |
200 | } | |
201 | EXPORT_SYMBOL_GPL(bsg_request_fn); | |
202 | ||
203 | /** | |
204 | * bsg_setup_queue - Create and add the bsg hooks so we can receive requests | |
205 | * @dev: device to attach bsg device to | |
206 | * @q: request queue setup by caller | |
207 | * @name: device to give bsg device | |
208 | * @job_fn: bsg job handler | |
209 | * @dd_job_size: size of LLD data needed for each job | |
210 | * | |
211 | * The caller should have setup the reuqest queue with bsg_request_fn | |
212 | * as the request_fn. | |
213 | */ | |
214 | int bsg_setup_queue(struct device *dev, struct request_queue *q, | |
215 | char *name, bsg_job_fn *job_fn, int dd_job_size) | |
216 | { | |
217 | int ret; | |
218 | ||
219 | q->queuedata = dev; | |
220 | q->bsg_job_size = dd_job_size; | |
221 | q->bsg_job_fn = job_fn; | |
222 | queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); | |
223 | blk_queue_softirq_done(q, bsg_softirq_done); | |
224 | blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); | |
225 | ||
226 | ret = bsg_register_queue(q, dev, name, NULL); | |
227 | if (ret) { | |
228 | printk(KERN_ERR "%s: bsg interface failed to " | |
229 | "initialize - register queue\n", dev->kobj.name); | |
230 | return ret; | |
231 | } | |
232 | ||
233 | return 0; | |
234 | } | |
235 | EXPORT_SYMBOL_GPL(bsg_setup_queue); |