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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, | |
a3bce90e FT |
44 | void __user *ubuf, unsigned int len, |
45 | gfp_t gfp_mask) | |
86db1e29 JA |
46 | { |
47 | unsigned long uaddr; | |
e3790c7d | 48 | unsigned int alignment; |
86db1e29 JA |
49 | struct bio *bio, *orig_bio; |
50 | int reading, ret; | |
51 | ||
52 | reading = rq_data_dir(rq) == READ; | |
53 | ||
54 | /* | |
55 | * if alignment requirement is satisfied, map in user pages for | |
56 | * direct dma. else, set up kernel bounce buffers | |
57 | */ | |
58 | uaddr = (unsigned long) ubuf; | |
e3790c7d TH |
59 | alignment = queue_dma_alignment(q) | q->dma_pad_mask; |
60 | if (!(uaddr & alignment) && !(len & alignment)) | |
a3bce90e | 61 | bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask); |
86db1e29 | 62 | else |
a3bce90e | 63 | bio = bio_copy_user(q, uaddr, len, reading, gfp_mask); |
86db1e29 JA |
64 | |
65 | if (IS_ERR(bio)) | |
66 | return PTR_ERR(bio); | |
67 | ||
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 |
86db1e29 JA |
90 | * @q: request queue where request should be inserted |
91 | * @rq: request structure to fill | |
92 | * @ubuf: the user buffer | |
93 | * @len: length of user data | |
a3bce90e | 94 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
95 | * |
96 | * Description: | |
710027a4 | 97 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
98 | * a kernel bounce buffer is used. |
99 | * | |
710027a4 | 100 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
101 | * still in process context. |
102 | * | |
103 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
104 | * before being submitted to the device, as pages mapped may be out of | |
105 | * reach. It's the callers responsibility to make sure this happens. The | |
106 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
107 | * unmapping. | |
108 | */ | |
109 | int blk_rq_map_user(struct request_queue *q, struct request *rq, | |
a3bce90e | 110 | void __user *ubuf, unsigned long len, gfp_t gfp_mask) |
86db1e29 JA |
111 | { |
112 | unsigned long bytes_read = 0; | |
113 | struct bio *bio = NULL; | |
114 | int ret; | |
115 | ||
116 | if (len > (q->max_hw_sectors << 9)) | |
117 | return -EINVAL; | |
118 | if (!len || !ubuf) | |
119 | return -EINVAL; | |
120 | ||
121 | while (bytes_read != len) { | |
122 | unsigned long map_len, end, start; | |
123 | ||
124 | map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); | |
125 | end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) | |
126 | >> PAGE_SHIFT; | |
127 | start = (unsigned long)ubuf >> PAGE_SHIFT; | |
128 | ||
129 | /* | |
130 | * A bad offset could cause us to require BIO_MAX_PAGES + 1 | |
131 | * pages. If this happens we just lower the requested | |
132 | * mapping len by a page so that we can fit | |
133 | */ | |
134 | if (end - start > BIO_MAX_PAGES) | |
135 | map_len -= PAGE_SIZE; | |
136 | ||
a3bce90e | 137 | ret = __blk_rq_map_user(q, rq, ubuf, map_len, gfp_mask); |
86db1e29 JA |
138 | if (ret < 0) |
139 | goto unmap_rq; | |
140 | if (!bio) | |
141 | bio = rq->bio; | |
142 | bytes_read += ret; | |
143 | ubuf += ret; | |
144 | } | |
145 | ||
f18573ab FT |
146 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
147 | rq->cmd_flags |= REQ_COPY_USER; | |
40b01b9b | 148 | |
86db1e29 JA |
149 | rq->buffer = rq->data = NULL; |
150 | return 0; | |
151 | unmap_rq: | |
152 | blk_rq_unmap_user(bio); | |
84e9e03c | 153 | rq->bio = NULL; |
86db1e29 JA |
154 | return ret; |
155 | } | |
86db1e29 JA |
156 | EXPORT_SYMBOL(blk_rq_map_user); |
157 | ||
158 | /** | |
710027a4 | 159 | * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
160 | * @q: request queue where request should be inserted |
161 | * @rq: request to map data to | |
162 | * @iov: pointer to the iovec | |
163 | * @iov_count: number of elements in the iovec | |
164 | * @len: I/O byte count | |
a3bce90e | 165 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
166 | * |
167 | * Description: | |
710027a4 | 168 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
169 | * a kernel bounce buffer is used. |
170 | * | |
710027a4 | 171 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
172 | * still in process context. |
173 | * | |
174 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
175 | * before being submitted to the device, as pages mapped may be out of | |
176 | * reach. It's the callers responsibility to make sure this happens. The | |
177 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
178 | * unmapping. | |
179 | */ | |
180 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
a3bce90e FT |
181 | struct sg_iovec *iov, int iov_count, unsigned int len, |
182 | gfp_t gfp_mask) | |
86db1e29 JA |
183 | { |
184 | struct bio *bio; | |
afdc1a78 FT |
185 | int i, read = rq_data_dir(rq) == READ; |
186 | int unaligned = 0; | |
86db1e29 JA |
187 | |
188 | if (!iov || iov_count <= 0) | |
189 | return -EINVAL; | |
190 | ||
afdc1a78 FT |
191 | for (i = 0; i < iov_count; i++) { |
192 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
193 | ||
194 | if (uaddr & queue_dma_alignment(q)) { | |
195 | unaligned = 1; | |
196 | break; | |
197 | } | |
198 | } | |
199 | ||
200 | if (unaligned || (q->dma_pad_mask & len)) | |
a3bce90e | 201 | bio = bio_copy_user_iov(q, iov, iov_count, read, gfp_mask); |
afdc1a78 | 202 | else |
a3bce90e | 203 | bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask); |
afdc1a78 | 204 | |
86db1e29 JA |
205 | if (IS_ERR(bio)) |
206 | return PTR_ERR(bio); | |
207 | ||
208 | if (bio->bi_size != len) { | |
209 | bio_endio(bio, 0); | |
210 | bio_unmap_user(bio); | |
211 | return -EINVAL; | |
212 | } | |
213 | ||
f18573ab FT |
214 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
215 | rq->cmd_flags |= REQ_COPY_USER; | |
216 | ||
07359fc6 | 217 | blk_queue_bounce(q, &bio); |
86db1e29 JA |
218 | bio_get(bio); |
219 | blk_rq_bio_prep(q, rq, bio); | |
220 | rq->buffer = rq->data = NULL; | |
221 | return 0; | |
222 | } | |
86db1e29 JA |
223 | |
224 | /** | |
225 | * blk_rq_unmap_user - unmap a request with user data | |
226 | * @bio: start of bio list | |
227 | * | |
228 | * Description: | |
229 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
230 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 231 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
232 | */ |
233 | int blk_rq_unmap_user(struct bio *bio) | |
234 | { | |
235 | struct bio *mapped_bio; | |
236 | int ret = 0, ret2; | |
237 | ||
238 | while (bio) { | |
239 | mapped_bio = bio; | |
240 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
241 | mapped_bio = bio->bi_private; | |
242 | ||
243 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
244 | if (ret2 && !ret) | |
245 | ret = ret2; | |
246 | ||
247 | mapped_bio = bio; | |
248 | bio = bio->bi_next; | |
249 | bio_put(mapped_bio); | |
250 | } | |
251 | ||
252 | return ret; | |
253 | } | |
86db1e29 JA |
254 | EXPORT_SYMBOL(blk_rq_unmap_user); |
255 | ||
256 | /** | |
710027a4 | 257 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
258 | * @q: request queue where request should be inserted |
259 | * @rq: request to fill | |
260 | * @kbuf: the kernel buffer | |
261 | * @len: length of user data | |
262 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
263 | * |
264 | * Description: | |
265 | * Data will be mapped directly if possible. Otherwise a bounce | |
266 | * buffer is used. | |
86db1e29 JA |
267 | */ |
268 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
269 | unsigned int len, gfp_t gfp_mask) | |
270 | { | |
68154e90 FT |
271 | unsigned long kaddr; |
272 | unsigned int alignment; | |
273 | int reading = rq_data_dir(rq) == READ; | |
274 | int do_copy = 0; | |
86db1e29 JA |
275 | struct bio *bio; |
276 | ||
277 | if (len > (q->max_hw_sectors << 9)) | |
278 | return -EINVAL; | |
279 | if (!len || !kbuf) | |
280 | return -EINVAL; | |
281 | ||
68154e90 FT |
282 | kaddr = (unsigned long)kbuf; |
283 | alignment = queue_dma_alignment(q) | q->dma_pad_mask; | |
a76eef95 FT |
284 | do_copy = ((kaddr & alignment) || (len & alignment) || |
285 | object_is_on_stack(kbuf)); | |
30c00eda | 286 | |
68154e90 FT |
287 | if (do_copy) |
288 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
289 | else | |
290 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
291 | ||
86db1e29 JA |
292 | if (IS_ERR(bio)) |
293 | return PTR_ERR(bio); | |
294 | ||
295 | if (rq_data_dir(rq) == WRITE) | |
296 | bio->bi_rw |= (1 << BIO_RW); | |
297 | ||
68154e90 FT |
298 | if (do_copy) |
299 | rq->cmd_flags |= REQ_COPY_USER; | |
300 | ||
86db1e29 JA |
301 | blk_rq_bio_prep(q, rq, bio); |
302 | blk_queue_bounce(q, &rq->bio); | |
303 | rq->buffer = rq->data = NULL; | |
304 | return 0; | |
305 | } | |
86db1e29 | 306 | EXPORT_SYMBOL(blk_rq_map_kern); |