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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 | */ | |
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 | ||
aa387cc8 MC |
154 | /** |
155 | * bsg_request_fn - generic handler for bsg requests | |
156 | * @q: request queue to manage | |
157 | * | |
158 | * On error the create_bsg_job function should return a -Exyz error value | |
159 | * that will be set to the req->errors. | |
160 | * | |
161 | * Drivers/subsys should pass this to the queue init function. | |
162 | */ | |
163 | void bsg_request_fn(struct request_queue *q) | |
164 | { | |
165 | struct device *dev = q->queuedata; | |
166 | struct request *req; | |
167 | struct bsg_job *job; | |
168 | int ret; | |
169 | ||
170 | if (!get_device(dev)) | |
171 | return; | |
172 | ||
173 | while (1) { | |
174 | req = blk_fetch_request(q); | |
175 | if (!req) | |
176 | break; | |
177 | spin_unlock_irq(q->queue_lock); | |
178 | ||
179 | ret = bsg_create_job(dev, req); | |
180 | if (ret) { | |
181 | req->errors = ret; | |
182 | blk_end_request_all(req, ret); | |
183 | spin_lock_irq(q->queue_lock); | |
184 | continue; | |
185 | } | |
186 | ||
187 | job = req->special; | |
188 | ret = q->bsg_job_fn(job); | |
189 | spin_lock_irq(q->queue_lock); | |
190 | if (ret) | |
191 | break; | |
192 | } | |
193 | ||
194 | spin_unlock_irq(q->queue_lock); | |
195 | put_device(dev); | |
196 | spin_lock_irq(q->queue_lock); | |
197 | } | |
198 | EXPORT_SYMBOL_GPL(bsg_request_fn); | |
199 | ||
200 | /** | |
201 | * bsg_setup_queue - Create and add the bsg hooks so we can receive requests | |
202 | * @dev: device to attach bsg device to | |
203 | * @q: request queue setup by caller | |
204 | * @name: device to give bsg device | |
205 | * @job_fn: bsg job handler | |
206 | * @dd_job_size: size of LLD data needed for each job | |
207 | * | |
208 | * The caller should have setup the reuqest queue with bsg_request_fn | |
209 | * as the request_fn. | |
210 | */ | |
211 | int bsg_setup_queue(struct device *dev, struct request_queue *q, | |
212 | char *name, bsg_job_fn *job_fn, int dd_job_size) | |
213 | { | |
214 | int ret; | |
215 | ||
216 | q->queuedata = dev; | |
217 | q->bsg_job_size = dd_job_size; | |
218 | q->bsg_job_fn = job_fn; | |
219 | queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); | |
220 | blk_queue_softirq_done(q, bsg_softirq_done); | |
221 | blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); | |
222 | ||
223 | ret = bsg_register_queue(q, dev, name, NULL); | |
224 | if (ret) { | |
225 | printk(KERN_ERR "%s: bsg interface failed to " | |
226 | "initialize - register queue\n", dev->kobj.name); | |
227 | return ret; | |
228 | } | |
229 | ||
230 | return 0; | |
231 | } | |
232 | EXPORT_SYMBOL_GPL(bsg_setup_queue); |