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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
[mirror_ubuntu-artful-kernel.git] / block / blk-map.c
CommitLineData
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1/*
2 * Functions related to mapping data to requests
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
afdc1a78 8#include <scsi/sg.h> /* for struct sg_iovec */
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9
10#include "blk.h"
11
12int blk_rq_append_bio(struct request_queue *q, struct request *rq,
13 struct bio *bio)
14{
15 if (!rq->bio)
16 blk_rq_bio_prep(q, rq, bio);
17 else if (!ll_back_merge_fn(q, rq, bio))
18 return -EINVAL;
19 else {
20 rq->biotail->bi_next = bio;
21 rq->biotail = bio;
22
a2dec7b3 23 rq->__data_len += bio->bi_size;
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24 }
25 return 0;
26}
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27
28static int __blk_rq_unmap_user(struct bio *bio)
29{
30 int ret = 0;
31
32 if (bio) {
33 if (bio_flagged(bio, BIO_USER_MAPPED))
34 bio_unmap_user(bio);
35 else
36 ret = bio_uncopy_user(bio);
37 }
38
39 return ret;
40}
41
42static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
152e283f 43 struct rq_map_data *map_data, void __user *ubuf,
97ae77a1 44 unsigned int len, gfp_t gfp_mask)
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45{
46 unsigned long uaddr;
47 struct bio *bio, *orig_bio;
48 int reading, ret;
49
50 reading = rq_data_dir(rq) == READ;
51
52 /*
53 * if alignment requirement is satisfied, map in user pages for
54 * direct dma. else, set up kernel bounce buffers
55 */
56 uaddr = (unsigned long) ubuf;
14417799 57 if (blk_rq_aligned(q, uaddr, len) && !map_data)
a3bce90e 58 bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
86db1e29 59 else
152e283f 60 bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask);
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61
62 if (IS_ERR(bio))
63 return PTR_ERR(bio);
64
97ae77a1 65 if (map_data && map_data->null_mapped)
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66 bio->bi_flags |= (1 << BIO_NULL_MAPPED);
67
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68 orig_bio = bio;
69 blk_queue_bounce(q, &bio);
70
71 /*
72 * We link the bounce buffer in and could have to traverse it
73 * later so we have to get a ref to prevent it from being freed
74 */
75 bio_get(bio);
76
77 ret = blk_rq_append_bio(q, rq, bio);
78 if (!ret)
79 return bio->bi_size;
80
81 /* if it was boucned we must call the end io function */
82 bio_endio(bio, 0);
83 __blk_rq_unmap_user(orig_bio);
84 bio_put(bio);
85 return ret;
86}
87
88/**
710027a4 89 * blk_rq_map_user - map user data to a request, for REQ_TYPE_BLOCK_PC usage
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90 * @q: request queue where request should be inserted
91 * @rq: request structure to fill
152e283f 92 * @map_data: pointer to the rq_map_data holding pages (if necessary)
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93 * @ubuf: the user buffer
94 * @len: length of user data
a3bce90e 95 * @gfp_mask: memory allocation flags
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96 *
97 * Description:
710027a4 98 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
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99 * a kernel bounce buffer is used.
100 *
710027a4 101 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
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102 * still in process context.
103 *
104 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
105 * before being submitted to the device, as pages mapped may be out of
106 * reach. It's the callers responsibility to make sure this happens. The
107 * original bio must be passed back in to blk_rq_unmap_user() for proper
108 * unmapping.
109 */
110int blk_rq_map_user(struct request_queue *q, struct request *rq,
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111 struct rq_map_data *map_data, void __user *ubuf,
112 unsigned long len, gfp_t gfp_mask)
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113{
114 unsigned long bytes_read = 0;
115 struct bio *bio = NULL;
97ae77a1 116 int ret;
86db1e29 117
ae03bf63 118 if (len > (queue_max_hw_sectors(q) << 9))
86db1e29 119 return -EINVAL;
81882766 120 if (!len)
86db1e29 121 return -EINVAL;
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122
123 if (!ubuf && (!map_data || !map_data->null_mapped))
124 return -EINVAL;
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125
126 while (bytes_read != len) {
127 unsigned long map_len, end, start;
128
129 map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
130 end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
131 >> PAGE_SHIFT;
132 start = (unsigned long)ubuf >> PAGE_SHIFT;
133
134 /*
135 * A bad offset could cause us to require BIO_MAX_PAGES + 1
136 * pages. If this happens we just lower the requested
137 * mapping len by a page so that we can fit
138 */
139 if (end - start > BIO_MAX_PAGES)
140 map_len -= PAGE_SIZE;
141
152e283f 142 ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len,
97ae77a1 143 gfp_mask);
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144 if (ret < 0)
145 goto unmap_rq;
146 if (!bio)
147 bio = rq->bio;
148 bytes_read += ret;
149 ubuf += ret;
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150
151 if (map_data)
152 map_data->offset += ret;
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153 }
154
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155 if (!bio_flagged(bio, BIO_USER_MAPPED))
156 rq->cmd_flags |= REQ_COPY_USER;
40b01b9b 157
731ec497 158 rq->buffer = NULL;
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159 return 0;
160unmap_rq:
161 blk_rq_unmap_user(bio);
84e9e03c 162 rq->bio = NULL;
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163 return ret;
164}
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165EXPORT_SYMBOL(blk_rq_map_user);
166
167/**
710027a4 168 * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
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169 * @q: request queue where request should be inserted
170 * @rq: request to map data to
152e283f 171 * @map_data: pointer to the rq_map_data holding pages (if necessary)
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172 * @iov: pointer to the iovec
173 * @iov_count: number of elements in the iovec
174 * @len: I/O byte count
a3bce90e 175 * @gfp_mask: memory allocation flags
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176 *
177 * Description:
710027a4 178 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
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179 * a kernel bounce buffer is used.
180 *
710027a4 181 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
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182 * still in process context.
183 *
184 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
185 * before being submitted to the device, as pages mapped may be out of
186 * reach. It's the callers responsibility to make sure this happens. The
187 * original bio must be passed back in to blk_rq_unmap_user() for proper
188 * unmapping.
189 */
190int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
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191 struct rq_map_data *map_data, struct sg_iovec *iov,
192 int iov_count, unsigned int len, gfp_t gfp_mask)
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193{
194 struct bio *bio;
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195 int i, read = rq_data_dir(rq) == READ;
196 int unaligned = 0;
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197
198 if (!iov || iov_count <= 0)
199 return -EINVAL;
200
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201 for (i = 0; i < iov_count; i++) {
202 unsigned long uaddr = (unsigned long)iov[i].iov_base;
203
204 if (uaddr & queue_dma_alignment(q)) {
205 unaligned = 1;
206 break;
207 }
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208 if (!iov[i].iov_len)
209 return -EINVAL;
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210 }
211
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212 if (unaligned || (q->dma_pad_mask & len) || map_data)
213 bio = bio_copy_user_iov(q, map_data, iov, iov_count, read,
214 gfp_mask);
afdc1a78 215 else
a3bce90e 216 bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask);
afdc1a78 217
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218 if (IS_ERR(bio))
219 return PTR_ERR(bio);
220
221 if (bio->bi_size != len) {
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222 /*
223 * Grab an extra reference to this bio, as bio_unmap_user()
224 * expects to be able to drop it twice as it happens on the
225 * normal IO completion path
226 */
227 bio_get(bio);
86db1e29 228 bio_endio(bio, 0);
53cc0b29 229 __blk_rq_unmap_user(bio);
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230 return -EINVAL;
231 }
232
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233 if (!bio_flagged(bio, BIO_USER_MAPPED))
234 rq->cmd_flags |= REQ_COPY_USER;
235
07359fc6 236 blk_queue_bounce(q, &bio);
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237 bio_get(bio);
238 blk_rq_bio_prep(q, rq, bio);
731ec497 239 rq->buffer = NULL;
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240 return 0;
241}
152e283f 242EXPORT_SYMBOL(blk_rq_map_user_iov);
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243
244/**
245 * blk_rq_unmap_user - unmap a request with user data
246 * @bio: start of bio list
247 *
248 * Description:
249 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
250 * supply the original rq->bio from the blk_rq_map_user() return, since
710027a4 251 * the I/O completion may have changed rq->bio.
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252 */
253int blk_rq_unmap_user(struct bio *bio)
254{
255 struct bio *mapped_bio;
256 int ret = 0, ret2;
257
258 while (bio) {
259 mapped_bio = bio;
260 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
261 mapped_bio = bio->bi_private;
262
263 ret2 = __blk_rq_unmap_user(mapped_bio);
264 if (ret2 && !ret)
265 ret = ret2;
266
267 mapped_bio = bio;
268 bio = bio->bi_next;
269 bio_put(mapped_bio);
270 }
271
272 return ret;
273}
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274EXPORT_SYMBOL(blk_rq_unmap_user);
275
276/**
710027a4 277 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
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278 * @q: request queue where request should be inserted
279 * @rq: request to fill
280 * @kbuf: the kernel buffer
281 * @len: length of user data
282 * @gfp_mask: memory allocation flags
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283 *
284 * Description:
285 * Data will be mapped directly if possible. Otherwise a bounce
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286 * buffer is used. Can be called multple times to append multple
287 * buffers.
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288 */
289int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
290 unsigned int len, gfp_t gfp_mask)
291{
68154e90 292 int reading = rq_data_dir(rq) == READ;
14417799 293 unsigned long addr = (unsigned long) kbuf;
68154e90 294 int do_copy = 0;
86db1e29 295 struct bio *bio;
3a5a3927 296 int ret;
86db1e29 297
ae03bf63 298 if (len > (queue_max_hw_sectors(q) << 9))
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299 return -EINVAL;
300 if (!len || !kbuf)
301 return -EINVAL;
302
14417799 303 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
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304 if (do_copy)
305 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
306 else
307 bio = bio_map_kern(q, kbuf, len, gfp_mask);
308
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309 if (IS_ERR(bio))
310 return PTR_ERR(bio);
311
312 if (rq_data_dir(rq) == WRITE)
a45dc2d2 313 bio->bi_rw |= REQ_WRITE;
86db1e29 314
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315 if (do_copy)
316 rq->cmd_flags |= REQ_COPY_USER;
317
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318 ret = blk_rq_append_bio(q, rq, bio);
319 if (unlikely(ret)) {
320 /* request is too big */
321 bio_put(bio);
322 return ret;
323 }
324
86db1e29 325 blk_queue_bounce(q, &rq->bio);
731ec497 326 rq->buffer = NULL;
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327 return 0;
328}
86db1e29 329EXPORT_SYMBOL(blk_rq_map_kern);