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86db1e29 JA |
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 */ |
86db1e29 JA |
9 | |
10 | #include "blk.h" | |
11 | ||
12 | int 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 | ||
23 | rq->data_len += bio->bi_size; | |
24 | } | |
25 | return 0; | |
26 | } | |
27 | EXPORT_SYMBOL(blk_rq_append_bio); | |
28 | ||
29 | static int __blk_rq_unmap_user(struct bio *bio) | |
30 | { | |
31 | int ret = 0; | |
32 | ||
33 | if (bio) { | |
34 | if (bio_flagged(bio, BIO_USER_MAPPED)) | |
35 | bio_unmap_user(bio); | |
36 | else | |
37 | ret = bio_uncopy_user(bio); | |
38 | } | |
39 | ||
40 | return ret; | |
41 | } | |
42 | ||
43 | static int __blk_rq_map_user(struct request_queue *q, struct request *rq, | |
152e283f | 44 | struct rq_map_data *map_data, void __user *ubuf, |
97ae77a1 | 45 | unsigned int len, gfp_t gfp_mask) |
86db1e29 JA |
46 | { |
47 | unsigned long uaddr; | |
48 | struct bio *bio, *orig_bio; | |
49 | int reading, ret; | |
50 | ||
51 | reading = rq_data_dir(rq) == READ; | |
52 | ||
53 | /* | |
54 | * if alignment requirement is satisfied, map in user pages for | |
55 | * direct dma. else, set up kernel bounce buffers | |
56 | */ | |
57 | uaddr = (unsigned long) ubuf; | |
87904074 | 58 | if (blk_rq_aligned(q, ubuf, len) && !map_data) |
a3bce90e | 59 | bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask); |
86db1e29 | 60 | else |
152e283f | 61 | bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask); |
86db1e29 JA |
62 | |
63 | if (IS_ERR(bio)) | |
64 | return PTR_ERR(bio); | |
65 | ||
97ae77a1 | 66 | if (map_data && map_data->null_mapped) |
81882766 FT |
67 | bio->bi_flags |= (1 << BIO_NULL_MAPPED); |
68 | ||
86db1e29 JA |
69 | orig_bio = bio; |
70 | blk_queue_bounce(q, &bio); | |
71 | ||
72 | /* | |
73 | * We link the bounce buffer in and could have to traverse it | |
74 | * later so we have to get a ref to prevent it from being freed | |
75 | */ | |
76 | bio_get(bio); | |
77 | ||
78 | ret = blk_rq_append_bio(q, rq, bio); | |
79 | if (!ret) | |
80 | return bio->bi_size; | |
81 | ||
82 | /* if it was boucned we must call the end io function */ | |
83 | bio_endio(bio, 0); | |
84 | __blk_rq_unmap_user(orig_bio); | |
85 | bio_put(bio); | |
86 | return ret; | |
87 | } | |
88 | ||
89 | /** | |
710027a4 | 90 | * blk_rq_map_user - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
91 | * @q: request queue where request should be inserted |
92 | * @rq: request structure to fill | |
152e283f | 93 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
86db1e29 JA |
94 | * @ubuf: the user buffer |
95 | * @len: length of user data | |
a3bce90e | 96 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
97 | * |
98 | * Description: | |
710027a4 | 99 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
100 | * a kernel bounce buffer is used. |
101 | * | |
710027a4 | 102 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
103 | * still in process context. |
104 | * | |
105 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
106 | * before being submitted to the device, as pages mapped may be out of | |
107 | * reach. It's the callers responsibility to make sure this happens. The | |
108 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
109 | * unmapping. | |
110 | */ | |
111 | int blk_rq_map_user(struct request_queue *q, struct request *rq, | |
152e283f FT |
112 | struct rq_map_data *map_data, void __user *ubuf, |
113 | unsigned long len, gfp_t gfp_mask) | |
86db1e29 JA |
114 | { |
115 | unsigned long bytes_read = 0; | |
116 | struct bio *bio = NULL; | |
97ae77a1 | 117 | int ret; |
86db1e29 JA |
118 | |
119 | if (len > (q->max_hw_sectors << 9)) | |
120 | return -EINVAL; | |
81882766 | 121 | if (!len) |
86db1e29 | 122 | return -EINVAL; |
97ae77a1 FT |
123 | |
124 | if (!ubuf && (!map_data || !map_data->null_mapped)) | |
125 | return -EINVAL; | |
86db1e29 JA |
126 | |
127 | while (bytes_read != len) { | |
128 | unsigned long map_len, end, start; | |
129 | ||
130 | map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); | |
131 | end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) | |
132 | >> PAGE_SHIFT; | |
133 | start = (unsigned long)ubuf >> PAGE_SHIFT; | |
134 | ||
135 | /* | |
136 | * A bad offset could cause us to require BIO_MAX_PAGES + 1 | |
137 | * pages. If this happens we just lower the requested | |
138 | * mapping len by a page so that we can fit | |
139 | */ | |
140 | if (end - start > BIO_MAX_PAGES) | |
141 | map_len -= PAGE_SIZE; | |
142 | ||
152e283f | 143 | ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len, |
97ae77a1 | 144 | gfp_mask); |
86db1e29 JA |
145 | if (ret < 0) |
146 | goto unmap_rq; | |
147 | if (!bio) | |
148 | bio = rq->bio; | |
149 | bytes_read += ret; | |
150 | ubuf += ret; | |
56c451f4 FT |
151 | |
152 | if (map_data) | |
153 | map_data->offset += ret; | |
86db1e29 JA |
154 | } |
155 | ||
f18573ab FT |
156 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
157 | rq->cmd_flags |= REQ_COPY_USER; | |
40b01b9b | 158 | |
86db1e29 JA |
159 | rq->buffer = rq->data = NULL; |
160 | return 0; | |
161 | unmap_rq: | |
162 | blk_rq_unmap_user(bio); | |
84e9e03c | 163 | rq->bio = NULL; |
86db1e29 JA |
164 | return ret; |
165 | } | |
86db1e29 JA |
166 | EXPORT_SYMBOL(blk_rq_map_user); |
167 | ||
168 | /** | |
710027a4 | 169 | * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
170 | * @q: request queue where request should be inserted |
171 | * @rq: request to map data to | |
152e283f | 172 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
86db1e29 JA |
173 | * @iov: pointer to the iovec |
174 | * @iov_count: number of elements in the iovec | |
175 | * @len: I/O byte count | |
a3bce90e | 176 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
177 | * |
178 | * Description: | |
710027a4 | 179 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
180 | * a kernel bounce buffer is used. |
181 | * | |
710027a4 | 182 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
183 | * still in process context. |
184 | * | |
185 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
186 | * before being submitted to the device, as pages mapped may be out of | |
187 | * reach. It's the callers responsibility to make sure this happens. The | |
188 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
189 | * unmapping. | |
190 | */ | |
191 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
152e283f FT |
192 | struct rq_map_data *map_data, struct sg_iovec *iov, |
193 | int iov_count, unsigned int len, gfp_t gfp_mask) | |
86db1e29 JA |
194 | { |
195 | struct bio *bio; | |
afdc1a78 FT |
196 | int i, read = rq_data_dir(rq) == READ; |
197 | int unaligned = 0; | |
86db1e29 JA |
198 | |
199 | if (!iov || iov_count <= 0) | |
200 | return -EINVAL; | |
201 | ||
afdc1a78 FT |
202 | for (i = 0; i < iov_count; i++) { |
203 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
204 | ||
205 | if (uaddr & queue_dma_alignment(q)) { | |
206 | unaligned = 1; | |
207 | break; | |
208 | } | |
209 | } | |
210 | ||
152e283f FT |
211 | if (unaligned || (q->dma_pad_mask & len) || map_data) |
212 | bio = bio_copy_user_iov(q, map_data, iov, iov_count, read, | |
213 | gfp_mask); | |
afdc1a78 | 214 | else |
a3bce90e | 215 | bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask); |
afdc1a78 | 216 | |
86db1e29 JA |
217 | if (IS_ERR(bio)) |
218 | return PTR_ERR(bio); | |
219 | ||
220 | if (bio->bi_size != len) { | |
c26156b2 JA |
221 | /* |
222 | * Grab an extra reference to this bio, as bio_unmap_user() | |
223 | * expects to be able to drop it twice as it happens on the | |
224 | * normal IO completion path | |
225 | */ | |
226 | bio_get(bio); | |
86db1e29 | 227 | bio_endio(bio, 0); |
53cc0b29 | 228 | __blk_rq_unmap_user(bio); |
86db1e29 JA |
229 | return -EINVAL; |
230 | } | |
231 | ||
f18573ab FT |
232 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
233 | rq->cmd_flags |= REQ_COPY_USER; | |
234 | ||
07359fc6 | 235 | blk_queue_bounce(q, &bio); |
86db1e29 JA |
236 | bio_get(bio); |
237 | blk_rq_bio_prep(q, rq, bio); | |
238 | rq->buffer = rq->data = NULL; | |
239 | return 0; | |
240 | } | |
152e283f | 241 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
86db1e29 JA |
242 | |
243 | /** | |
244 | * blk_rq_unmap_user - unmap a request with user data | |
245 | * @bio: start of bio list | |
246 | * | |
247 | * Description: | |
248 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
249 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 250 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
251 | */ |
252 | int blk_rq_unmap_user(struct bio *bio) | |
253 | { | |
254 | struct bio *mapped_bio; | |
255 | int ret = 0, ret2; | |
256 | ||
257 | while (bio) { | |
258 | mapped_bio = bio; | |
259 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
260 | mapped_bio = bio->bi_private; | |
261 | ||
262 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
263 | if (ret2 && !ret) | |
264 | ret = ret2; | |
265 | ||
266 | mapped_bio = bio; | |
267 | bio = bio->bi_next; | |
268 | bio_put(mapped_bio); | |
269 | } | |
270 | ||
271 | return ret; | |
272 | } | |
86db1e29 JA |
273 | EXPORT_SYMBOL(blk_rq_unmap_user); |
274 | ||
275 | /** | |
710027a4 | 276 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
277 | * @q: request queue where request should be inserted |
278 | * @rq: request to fill | |
279 | * @kbuf: the kernel buffer | |
280 | * @len: length of user data | |
281 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
282 | * |
283 | * Description: | |
284 | * Data will be mapped directly if possible. Otherwise a bounce | |
285 | * buffer is used. | |
86db1e29 JA |
286 | */ |
287 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
288 | unsigned int len, gfp_t gfp_mask) | |
289 | { | |
68154e90 FT |
290 | int reading = rq_data_dir(rq) == READ; |
291 | int do_copy = 0; | |
86db1e29 JA |
292 | struct bio *bio; |
293 | ||
294 | if (len > (q->max_hw_sectors << 9)) | |
295 | return -EINVAL; | |
296 | if (!len || !kbuf) | |
297 | return -EINVAL; | |
298 | ||
87904074 | 299 | do_copy = !blk_rq_aligned(q, kbuf, len) || object_is_on_stack(kbuf); |
68154e90 FT |
300 | if (do_copy) |
301 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
302 | else | |
303 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
304 | ||
86db1e29 JA |
305 | if (IS_ERR(bio)) |
306 | return PTR_ERR(bio); | |
307 | ||
308 | if (rq_data_dir(rq) == WRITE) | |
309 | bio->bi_rw |= (1 << BIO_RW); | |
310 | ||
68154e90 FT |
311 | if (do_copy) |
312 | rq->cmd_flags |= REQ_COPY_USER; | |
313 | ||
86db1e29 JA |
314 | blk_rq_bio_prep(q, rq, bio); |
315 | blk_queue_bounce(q, &rq->bio); | |
316 | rq->buffer = rq->data = NULL; | |
317 | return 0; | |
318 | } | |
86db1e29 | 319 | EXPORT_SYMBOL(blk_rq_map_kern); |