Commit | Line | Data |
---|---|---|
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> | |
26e49cfc | 8 | #include <linux/uio.h> |
86db1e29 JA |
9 | |
10 | #include "blk.h" | |
11 | ||
46348456 SG |
12 | static bool iovec_gap_to_prv(struct request_queue *q, |
13 | struct iovec *prv, struct iovec *cur) | |
14 | { | |
15 | unsigned long prev_end; | |
16 | ||
17 | if (!queue_virt_boundary(q)) | |
18 | return false; | |
19 | ||
20 | if (prv->iov_base == NULL && prv->iov_len == 0) | |
21 | /* prv is not set - don't check */ | |
22 | return false; | |
23 | ||
24 | prev_end = (unsigned long)(prv->iov_base + prv->iov_len); | |
25 | ||
26 | return (((unsigned long)cur->iov_base & queue_virt_boundary(q)) || | |
27 | prev_end & queue_virt_boundary(q)); | |
28 | } | |
29 | ||
86db1e29 JA |
30 | int blk_rq_append_bio(struct request_queue *q, struct request *rq, |
31 | struct bio *bio) | |
32 | { | |
33 | if (!rq->bio) | |
34 | blk_rq_bio_prep(q, rq, bio); | |
35 | else if (!ll_back_merge_fn(q, rq, bio)) | |
36 | return -EINVAL; | |
37 | else { | |
38 | rq->biotail->bi_next = bio; | |
39 | rq->biotail = bio; | |
40 | ||
4f024f37 | 41 | rq->__data_len += bio->bi_iter.bi_size; |
86db1e29 JA |
42 | } |
43 | return 0; | |
44 | } | |
86db1e29 JA |
45 | |
46 | static int __blk_rq_unmap_user(struct bio *bio) | |
47 | { | |
48 | int ret = 0; | |
49 | ||
50 | if (bio) { | |
51 | if (bio_flagged(bio, BIO_USER_MAPPED)) | |
52 | bio_unmap_user(bio); | |
53 | else | |
54 | ret = bio_uncopy_user(bio); | |
55 | } | |
56 | ||
57 | return ret; | |
58 | } | |
59 | ||
4d6af73d CH |
60 | static int __blk_rq_map_user_iov(struct request *rq, |
61 | struct rq_map_data *map_data, struct iov_iter *iter, | |
62 | gfp_t gfp_mask, bool copy) | |
63 | { | |
64 | struct request_queue *q = rq->q; | |
65 | struct bio *bio, *orig_bio; | |
66 | int ret; | |
67 | ||
68 | if (copy) | |
69 | bio = bio_copy_user_iov(q, map_data, iter, gfp_mask); | |
70 | else | |
71 | bio = bio_map_user_iov(q, iter, gfp_mask); | |
72 | ||
73 | if (IS_ERR(bio)) | |
74 | return PTR_ERR(bio); | |
75 | ||
76 | if (map_data && map_data->null_mapped) | |
77 | bio_set_flag(bio, BIO_NULL_MAPPED); | |
78 | ||
79 | iov_iter_advance(iter, bio->bi_iter.bi_size); | |
80 | if (map_data) | |
81 | map_data->offset += bio->bi_iter.bi_size; | |
82 | ||
83 | orig_bio = bio; | |
84 | blk_queue_bounce(q, &bio); | |
85 | ||
86 | /* | |
87 | * We link the bounce buffer in and could have to traverse it | |
88 | * later so we have to get a ref to prevent it from being freed | |
89 | */ | |
90 | bio_get(bio); | |
91 | ||
92 | ret = blk_rq_append_bio(q, rq, bio); | |
93 | if (ret) { | |
94 | bio_endio(bio); | |
95 | __blk_rq_unmap_user(orig_bio); | |
96 | bio_put(bio); | |
97 | return ret; | |
98 | } | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
86db1e29 | 103 | /** |
710027a4 | 104 | * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
105 | * @q: request queue where request should be inserted |
106 | * @rq: request to map data to | |
152e283f | 107 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
26e49cfc | 108 | * @iter: iovec iterator |
a3bce90e | 109 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
110 | * |
111 | * Description: | |
710027a4 | 112 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
113 | * a kernel bounce buffer is used. |
114 | * | |
710027a4 | 115 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
116 | * still in process context. |
117 | * | |
118 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
119 | * before being submitted to the device, as pages mapped may be out of | |
120 | * reach. It's the callers responsibility to make sure this happens. The | |
121 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
122 | * unmapping. | |
123 | */ | |
124 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
26e49cfc KO |
125 | struct rq_map_data *map_data, |
126 | const struct iov_iter *iter, gfp_t gfp_mask) | |
86db1e29 | 127 | { |
46348456 | 128 | struct iovec iov, prv = {.iov_base = NULL, .iov_len = 0}; |
4d6af73d CH |
129 | bool copy = (q->dma_pad_mask & iter->count) || map_data; |
130 | struct bio *bio = NULL; | |
131 | struct iov_iter i; | |
132 | int ret; | |
86db1e29 | 133 | |
26e49cfc | 134 | if (!iter || !iter->count) |
86db1e29 JA |
135 | return -EINVAL; |
136 | ||
26e49cfc KO |
137 | iov_for_each(iov, i, *iter) { |
138 | unsigned long uaddr = (unsigned long) iov.iov_base; | |
afdc1a78 | 139 | |
26e49cfc | 140 | if (!iov.iov_len) |
54787556 XF |
141 | return -EINVAL; |
142 | ||
6b76106d BH |
143 | /* |
144 | * Keep going so we check length of all segments | |
145 | */ | |
46348456 SG |
146 | if ((uaddr & queue_dma_alignment(q)) || |
147 | iovec_gap_to_prv(q, &prv, &iov)) | |
4d6af73d | 148 | copy = true; |
46348456 SG |
149 | |
150 | prv.iov_base = iov.iov_base; | |
151 | prv.iov_len = iov.iov_len; | |
afdc1a78 FT |
152 | } |
153 | ||
4d6af73d CH |
154 | i = *iter; |
155 | do { | |
156 | ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); | |
157 | if (ret) | |
158 | goto unmap_rq; | |
159 | if (!bio) | |
160 | bio = rq->bio; | |
161 | } while (iov_iter_count(&i)); | |
86db1e29 | 162 | |
f18573ab FT |
163 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
164 | rq->cmd_flags |= REQ_COPY_USER; | |
86db1e29 | 165 | return 0; |
4d6af73d CH |
166 | |
167 | unmap_rq: | |
168 | __blk_rq_unmap_user(bio); | |
169 | rq->bio = NULL; | |
170 | return -EINVAL; | |
86db1e29 | 171 | } |
152e283f | 172 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
86db1e29 | 173 | |
ddad8dd0 CH |
174 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
175 | struct rq_map_data *map_data, void __user *ubuf, | |
176 | unsigned long len, gfp_t gfp_mask) | |
177 | { | |
26e49cfc KO |
178 | struct iovec iov; |
179 | struct iov_iter i; | |
8f7e885a | 180 | int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i); |
ddad8dd0 | 181 | |
8f7e885a AV |
182 | if (unlikely(ret < 0)) |
183 | return ret; | |
ddad8dd0 | 184 | |
26e49cfc | 185 | return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask); |
ddad8dd0 CH |
186 | } |
187 | EXPORT_SYMBOL(blk_rq_map_user); | |
188 | ||
86db1e29 JA |
189 | /** |
190 | * blk_rq_unmap_user - unmap a request with user data | |
191 | * @bio: start of bio list | |
192 | * | |
193 | * Description: | |
194 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
195 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 196 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
197 | */ |
198 | int blk_rq_unmap_user(struct bio *bio) | |
199 | { | |
200 | struct bio *mapped_bio; | |
201 | int ret = 0, ret2; | |
202 | ||
203 | while (bio) { | |
204 | mapped_bio = bio; | |
205 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
206 | mapped_bio = bio->bi_private; | |
207 | ||
208 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
209 | if (ret2 && !ret) | |
210 | ret = ret2; | |
211 | ||
212 | mapped_bio = bio; | |
213 | bio = bio->bi_next; | |
214 | bio_put(mapped_bio); | |
215 | } | |
216 | ||
217 | return ret; | |
218 | } | |
86db1e29 JA |
219 | EXPORT_SYMBOL(blk_rq_unmap_user); |
220 | ||
221 | /** | |
710027a4 | 222 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
223 | * @q: request queue where request should be inserted |
224 | * @rq: request to fill | |
225 | * @kbuf: the kernel buffer | |
226 | * @len: length of user data | |
227 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
228 | * |
229 | * Description: | |
230 | * Data will be mapped directly if possible. Otherwise a bounce | |
e227867f | 231 | * buffer is used. Can be called multiple times to append multiple |
3a5a3927 | 232 | * buffers. |
86db1e29 JA |
233 | */ |
234 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
235 | unsigned int len, gfp_t gfp_mask) | |
236 | { | |
68154e90 | 237 | int reading = rq_data_dir(rq) == READ; |
14417799 | 238 | unsigned long addr = (unsigned long) kbuf; |
68154e90 | 239 | int do_copy = 0; |
86db1e29 | 240 | struct bio *bio; |
3a5a3927 | 241 | int ret; |
86db1e29 | 242 | |
ae03bf63 | 243 | if (len > (queue_max_hw_sectors(q) << 9)) |
86db1e29 JA |
244 | return -EINVAL; |
245 | if (!len || !kbuf) | |
246 | return -EINVAL; | |
247 | ||
14417799 | 248 | do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf); |
68154e90 FT |
249 | if (do_copy) |
250 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
251 | else | |
252 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
253 | ||
86db1e29 JA |
254 | if (IS_ERR(bio)) |
255 | return PTR_ERR(bio); | |
256 | ||
609f6ea1 | 257 | if (!reading) |
a45dc2d2 | 258 | bio->bi_rw |= REQ_WRITE; |
86db1e29 | 259 | |
68154e90 FT |
260 | if (do_copy) |
261 | rq->cmd_flags |= REQ_COPY_USER; | |
262 | ||
3a5a3927 JB |
263 | ret = blk_rq_append_bio(q, rq, bio); |
264 | if (unlikely(ret)) { | |
265 | /* request is too big */ | |
266 | bio_put(bio); | |
267 | return ret; | |
268 | } | |
269 | ||
86db1e29 | 270 | blk_queue_bounce(q, &rq->bio); |
86db1e29 JA |
271 | return 0; |
272 | } | |
86db1e29 | 273 | EXPORT_SYMBOL(blk_rq_map_kern); |