Commit | Line | Data |
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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> | |
8 | ||
9 | #include "blk.h" | |
10 | ||
11 | int blk_rq_append_bio(struct request_queue *q, struct request *rq, | |
12 | struct bio *bio) | |
13 | { | |
14 | if (!rq->bio) | |
15 | blk_rq_bio_prep(q, rq, bio); | |
16 | else if (!ll_back_merge_fn(q, rq, bio)) | |
17 | return -EINVAL; | |
18 | else { | |
19 | rq->biotail->bi_next = bio; | |
20 | rq->biotail = bio; | |
21 | ||
22 | rq->data_len += bio->bi_size; | |
23 | } | |
24 | return 0; | |
25 | } | |
26 | EXPORT_SYMBOL(blk_rq_append_bio); | |
27 | ||
28 | static 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 | ||
42 | static int __blk_rq_map_user(struct request_queue *q, struct request *rq, | |
43 | void __user *ubuf, unsigned int len) | |
44 | { | |
45 | unsigned long uaddr; | |
e3790c7d | 46 | unsigned int alignment; |
86db1e29 JA |
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; | |
e3790c7d TH |
57 | alignment = queue_dma_alignment(q) | q->dma_pad_mask; |
58 | if (!(uaddr & alignment) && !(len & alignment)) | |
86db1e29 JA |
59 | bio = bio_map_user(q, NULL, uaddr, len, reading); |
60 | else | |
61 | bio = bio_copy_user(q, uaddr, len, reading); | |
62 | ||
63 | if (IS_ERR(bio)) | |
64 | return PTR_ERR(bio); | |
65 | ||
66 | orig_bio = bio; | |
67 | blk_queue_bounce(q, &bio); | |
68 | ||
69 | /* | |
70 | * We link the bounce buffer in and could have to traverse it | |
71 | * later so we have to get a ref to prevent it from being freed | |
72 | */ | |
73 | bio_get(bio); | |
74 | ||
75 | ret = blk_rq_append_bio(q, rq, bio); | |
76 | if (!ret) | |
77 | return bio->bi_size; | |
78 | ||
79 | /* if it was boucned we must call the end io function */ | |
80 | bio_endio(bio, 0); | |
81 | __blk_rq_unmap_user(orig_bio); | |
82 | bio_put(bio); | |
83 | return ret; | |
84 | } | |
85 | ||
86 | /** | |
87 | * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage | |
88 | * @q: request queue where request should be inserted | |
89 | * @rq: request structure to fill | |
90 | * @ubuf: the user buffer | |
91 | * @len: length of user data | |
92 | * | |
93 | * Description: | |
94 | * Data will be mapped directly for zero copy io, if possible. Otherwise | |
95 | * a kernel bounce buffer is used. | |
96 | * | |
97 | * A matching blk_rq_unmap_user() must be issued at the end of io, while | |
98 | * still in process context. | |
99 | * | |
100 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
101 | * before being submitted to the device, as pages mapped may be out of | |
102 | * reach. It's the callers responsibility to make sure this happens. The | |
103 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
104 | * unmapping. | |
105 | */ | |
106 | int blk_rq_map_user(struct request_queue *q, struct request *rq, | |
107 | void __user *ubuf, unsigned long len) | |
108 | { | |
109 | unsigned long bytes_read = 0; | |
110 | struct bio *bio = NULL; | |
111 | int ret; | |
112 | ||
113 | if (len > (q->max_hw_sectors << 9)) | |
114 | return -EINVAL; | |
115 | if (!len || !ubuf) | |
116 | return -EINVAL; | |
117 | ||
118 | while (bytes_read != len) { | |
119 | unsigned long map_len, end, start; | |
120 | ||
121 | map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); | |
122 | end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) | |
123 | >> PAGE_SHIFT; | |
124 | start = (unsigned long)ubuf >> PAGE_SHIFT; | |
125 | ||
126 | /* | |
127 | * A bad offset could cause us to require BIO_MAX_PAGES + 1 | |
128 | * pages. If this happens we just lower the requested | |
129 | * mapping len by a page so that we can fit | |
130 | */ | |
131 | if (end - start > BIO_MAX_PAGES) | |
132 | map_len -= PAGE_SIZE; | |
133 | ||
134 | ret = __blk_rq_map_user(q, rq, ubuf, map_len); | |
135 | if (ret < 0) | |
136 | goto unmap_rq; | |
137 | if (!bio) | |
138 | bio = rq->bio; | |
139 | bytes_read += ret; | |
140 | ubuf += ret; | |
141 | } | |
142 | ||
40b01b9b TH |
143 | /* |
144 | * __blk_rq_map_user() copies the buffers if starting address | |
e3790c7d TH |
145 | * or length isn't aligned to dma_pad_mask. As the copied |
146 | * buffer is always page aligned, we know that there's enough | |
147 | * room for padding. Extend the last bio and update | |
148 | * rq->data_len accordingly. | |
40b01b9b TH |
149 | * |
150 | * On unmap, bio_uncopy_user() will use unmodified | |
151 | * bio_map_data pointed to by bio->bi_private. | |
152 | */ | |
e3790c7d TH |
153 | if (len & q->dma_pad_mask) { |
154 | unsigned int pad_len = (q->dma_pad_mask & ~len) + 1; | |
56d94a37 | 155 | struct bio *tail = rq->biotail; |
e3790c7d | 156 | |
56d94a37 HH |
157 | tail->bi_io_vec[tail->bi_vcnt - 1].bv_len += pad_len; |
158 | tail->bi_size += pad_len; | |
40b01b9b | 159 | |
7a85f889 | 160 | rq->extra_len += pad_len; |
40b01b9b TH |
161 | } |
162 | ||
86db1e29 JA |
163 | rq->buffer = rq->data = NULL; |
164 | return 0; | |
165 | unmap_rq: | |
166 | blk_rq_unmap_user(bio); | |
84e9e03c | 167 | rq->bio = NULL; |
86db1e29 JA |
168 | return ret; |
169 | } | |
86db1e29 JA |
170 | EXPORT_SYMBOL(blk_rq_map_user); |
171 | ||
172 | /** | |
173 | * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage | |
174 | * @q: request queue where request should be inserted | |
175 | * @rq: request to map data to | |
176 | * @iov: pointer to the iovec | |
177 | * @iov_count: number of elements in the iovec | |
178 | * @len: I/O byte count | |
179 | * | |
180 | * Description: | |
181 | * Data will be mapped directly for zero copy io, if possible. Otherwise | |
182 | * a kernel bounce buffer is used. | |
183 | * | |
184 | * A matching blk_rq_unmap_user() must be issued at the end of io, while | |
185 | * still in process context. | |
186 | * | |
187 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
188 | * before being submitted to the device, as pages mapped may be out of | |
189 | * reach. It's the callers responsibility to make sure this happens. The | |
190 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
191 | * unmapping. | |
192 | */ | |
193 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
194 | struct sg_iovec *iov, int iov_count, unsigned int len) | |
195 | { | |
196 | struct bio *bio; | |
197 | ||
198 | if (!iov || iov_count <= 0) | |
199 | return -EINVAL; | |
200 | ||
201 | /* we don't allow misaligned data like bio_map_user() does. If the | |
202 | * user is using sg, they're expected to know the alignment constraints | |
203 | * and respect them accordingly */ | |
6728cb0e JA |
204 | bio = bio_map_user_iov(q, NULL, iov, iov_count, |
205 | rq_data_dir(rq) == READ); | |
86db1e29 JA |
206 | if (IS_ERR(bio)) |
207 | return PTR_ERR(bio); | |
208 | ||
209 | if (bio->bi_size != len) { | |
210 | bio_endio(bio, 0); | |
211 | bio_unmap_user(bio); | |
212 | return -EINVAL; | |
213 | } | |
214 | ||
215 | bio_get(bio); | |
216 | blk_rq_bio_prep(q, rq, bio); | |
217 | rq->buffer = rq->data = NULL; | |
218 | return 0; | |
219 | } | |
86db1e29 JA |
220 | |
221 | /** | |
222 | * blk_rq_unmap_user - unmap a request with user data | |
223 | * @bio: start of bio list | |
224 | * | |
225 | * Description: | |
226 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
227 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
228 | * the io completion may have changed rq->bio. | |
229 | */ | |
230 | int blk_rq_unmap_user(struct bio *bio) | |
231 | { | |
232 | struct bio *mapped_bio; | |
233 | int ret = 0, ret2; | |
234 | ||
235 | while (bio) { | |
236 | mapped_bio = bio; | |
237 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
238 | mapped_bio = bio->bi_private; | |
239 | ||
240 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
241 | if (ret2 && !ret) | |
242 | ret = ret2; | |
243 | ||
244 | mapped_bio = bio; | |
245 | bio = bio->bi_next; | |
246 | bio_put(mapped_bio); | |
247 | } | |
248 | ||
249 | return ret; | |
250 | } | |
86db1e29 JA |
251 | EXPORT_SYMBOL(blk_rq_unmap_user); |
252 | ||
253 | /** | |
254 | * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage | |
255 | * @q: request queue where request should be inserted | |
256 | * @rq: request to fill | |
257 | * @kbuf: the kernel buffer | |
258 | * @len: length of user data | |
259 | * @gfp_mask: memory allocation flags | |
260 | */ | |
261 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
262 | unsigned int len, gfp_t gfp_mask) | |
263 | { | |
264 | struct bio *bio; | |
265 | ||
266 | if (len > (q->max_hw_sectors << 9)) | |
267 | return -EINVAL; | |
268 | if (!len || !kbuf) | |
269 | return -EINVAL; | |
270 | ||
271 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
272 | if (IS_ERR(bio)) | |
273 | return PTR_ERR(bio); | |
274 | ||
275 | if (rq_data_dir(rq) == WRITE) | |
276 | bio->bi_rw |= (1 << BIO_RW); | |
277 | ||
278 | blk_rq_bio_prep(q, rq, bio); | |
279 | blk_queue_bounce(q, &rq->bio); | |
280 | rq->buffer = rq->data = NULL; | |
281 | return 0; | |
282 | } | |
86db1e29 | 283 | EXPORT_SYMBOL(blk_rq_map_kern); |