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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
86db1e29 JA |
2 | /* |
3 | * Functions related to mapping data to requests | |
4 | */ | |
5 | #include <linux/kernel.h> | |
68db0cf1 | 6 | #include <linux/sched/task_stack.h> |
86db1e29 JA |
7 | #include <linux/module.h> |
8 | #include <linux/bio.h> | |
9 | #include <linux/blkdev.h> | |
26e49cfc | 10 | #include <linux/uio.h> |
86db1e29 JA |
11 | |
12 | #include "blk.h" | |
13 | ||
98d61d5b CH |
14 | /* |
15 | * Append a bio to a passthrough request. Only works can be merged into | |
16 | * the request based on the driver constraints. | |
17 | */ | |
18 | int blk_rq_append_bio(struct request *rq, struct bio *bio) | |
86db1e29 | 19 | { |
caa4b024 CH |
20 | blk_queue_bounce(rq->q, &bio); |
21 | ||
98d61d5b CH |
22 | if (!rq->bio) { |
23 | blk_rq_bio_prep(rq->q, rq, bio); | |
24 | } else { | |
25 | if (!ll_back_merge_fn(rq->q, rq, bio)) | |
26 | return -EINVAL; | |
27 | ||
86db1e29 JA |
28 | rq->biotail->bi_next = bio; |
29 | rq->biotail = bio; | |
4f024f37 | 30 | rq->__data_len += bio->bi_iter.bi_size; |
86db1e29 | 31 | } |
98d61d5b | 32 | |
86db1e29 JA |
33 | return 0; |
34 | } | |
98d61d5b | 35 | EXPORT_SYMBOL(blk_rq_append_bio); |
86db1e29 JA |
36 | |
37 | static int __blk_rq_unmap_user(struct bio *bio) | |
38 | { | |
39 | int ret = 0; | |
40 | ||
41 | if (bio) { | |
42 | if (bio_flagged(bio, BIO_USER_MAPPED)) | |
43 | bio_unmap_user(bio); | |
44 | else | |
45 | ret = bio_uncopy_user(bio); | |
46 | } | |
47 | ||
48 | return ret; | |
49 | } | |
50 | ||
4d6af73d CH |
51 | static int __blk_rq_map_user_iov(struct request *rq, |
52 | struct rq_map_data *map_data, struct iov_iter *iter, | |
53 | gfp_t gfp_mask, bool copy) | |
54 | { | |
55 | struct request_queue *q = rq->q; | |
56 | struct bio *bio, *orig_bio; | |
57 | int ret; | |
58 | ||
59 | if (copy) | |
60 | bio = bio_copy_user_iov(q, map_data, iter, gfp_mask); | |
61 | else | |
62 | bio = bio_map_user_iov(q, iter, gfp_mask); | |
63 | ||
64 | if (IS_ERR(bio)) | |
65 | return PTR_ERR(bio); | |
66 | ||
aebf526b CH |
67 | bio->bi_opf &= ~REQ_OP_MASK; |
68 | bio->bi_opf |= req_op(rq); | |
69 | ||
4d6af73d CH |
70 | if (map_data && map_data->null_mapped) |
71 | bio_set_flag(bio, BIO_NULL_MAPPED); | |
72 | ||
73 | iov_iter_advance(iter, bio->bi_iter.bi_size); | |
74 | if (map_data) | |
75 | map_data->offset += bio->bi_iter.bi_size; | |
76 | ||
77 | orig_bio = bio; | |
4d6af73d CH |
78 | |
79 | /* | |
80 | * We link the bounce buffer in and could have to traverse it | |
81 | * later so we have to get a ref to prevent it from being freed | |
82 | */ | |
98d61d5b | 83 | ret = blk_rq_append_bio(rq, bio); |
caa4b024 | 84 | bio_get(bio); |
4d6af73d CH |
85 | if (ret) { |
86 | bio_endio(bio); | |
87 | __blk_rq_unmap_user(orig_bio); | |
88 | bio_put(bio); | |
89 | return ret; | |
90 | } | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
86db1e29 | 95 | /** |
aebf526b | 96 | * blk_rq_map_user_iov - map user data to a request, for passthrough requests |
86db1e29 JA |
97 | * @q: request queue where request should be inserted |
98 | * @rq: request to map data to | |
152e283f | 99 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
26e49cfc | 100 | * @iter: iovec iterator |
a3bce90e | 101 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
102 | * |
103 | * Description: | |
710027a4 | 104 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
105 | * a kernel bounce buffer is used. |
106 | * | |
710027a4 | 107 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
108 | * still in process context. |
109 | * | |
110 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
111 | * before being submitted to the device, as pages mapped may be out of | |
112 | * reach. It's the callers responsibility to make sure this happens. The | |
113 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
114 | * unmapping. | |
115 | */ | |
116 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
26e49cfc KO |
117 | struct rq_map_data *map_data, |
118 | const struct iov_iter *iter, gfp_t gfp_mask) | |
86db1e29 | 119 | { |
357f435d AV |
120 | bool copy = false; |
121 | unsigned long align = q->dma_pad_mask | queue_dma_alignment(q); | |
4d6af73d CH |
122 | struct bio *bio = NULL; |
123 | struct iov_iter i; | |
124 | int ret; | |
86db1e29 | 125 | |
a0ac402c LT |
126 | if (!iter_is_iovec(iter)) |
127 | goto fail; | |
128 | ||
357f435d AV |
129 | if (map_data) |
130 | copy = true; | |
131 | else if (iov_iter_alignment(iter) & align) | |
132 | copy = true; | |
133 | else if (queue_virt_boundary(q)) | |
134 | copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter); | |
afdc1a78 | 135 | |
4d6af73d CH |
136 | i = *iter; |
137 | do { | |
138 | ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); | |
139 | if (ret) | |
140 | goto unmap_rq; | |
141 | if (!bio) | |
142 | bio = rq->bio; | |
143 | } while (iov_iter_count(&i)); | |
86db1e29 | 144 | |
f18573ab | 145 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
e8064021 | 146 | rq->rq_flags |= RQF_COPY_USER; |
86db1e29 | 147 | return 0; |
4d6af73d CH |
148 | |
149 | unmap_rq: | |
150 | __blk_rq_unmap_user(bio); | |
a0ac402c | 151 | fail: |
4d6af73d CH |
152 | rq->bio = NULL; |
153 | return -EINVAL; | |
86db1e29 | 154 | } |
152e283f | 155 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
86db1e29 | 156 | |
ddad8dd0 CH |
157 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
158 | struct rq_map_data *map_data, void __user *ubuf, | |
159 | unsigned long len, gfp_t gfp_mask) | |
160 | { | |
26e49cfc KO |
161 | struct iovec iov; |
162 | struct iov_iter i; | |
8f7e885a | 163 | int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i); |
ddad8dd0 | 164 | |
8f7e885a AV |
165 | if (unlikely(ret < 0)) |
166 | return ret; | |
ddad8dd0 | 167 | |
26e49cfc | 168 | return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask); |
ddad8dd0 CH |
169 | } |
170 | EXPORT_SYMBOL(blk_rq_map_user); | |
171 | ||
86db1e29 JA |
172 | /** |
173 | * blk_rq_unmap_user - unmap a request with user data | |
174 | * @bio: start of bio list | |
175 | * | |
176 | * Description: | |
177 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
178 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 179 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
180 | */ |
181 | int blk_rq_unmap_user(struct bio *bio) | |
182 | { | |
183 | struct bio *mapped_bio; | |
184 | int ret = 0, ret2; | |
185 | ||
186 | while (bio) { | |
187 | mapped_bio = bio; | |
188 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
189 | mapped_bio = bio->bi_private; | |
190 | ||
191 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
192 | if (ret2 && !ret) | |
193 | ret = ret2; | |
194 | ||
195 | mapped_bio = bio; | |
196 | bio = bio->bi_next; | |
197 | bio_put(mapped_bio); | |
198 | } | |
199 | ||
200 | return ret; | |
201 | } | |
86db1e29 JA |
202 | EXPORT_SYMBOL(blk_rq_unmap_user); |
203 | ||
204 | /** | |
aebf526b | 205 | * blk_rq_map_kern - map kernel data to a request, for passthrough requests |
86db1e29 JA |
206 | * @q: request queue where request should be inserted |
207 | * @rq: request to fill | |
208 | * @kbuf: the kernel buffer | |
209 | * @len: length of user data | |
210 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
211 | * |
212 | * Description: | |
213 | * Data will be mapped directly if possible. Otherwise a bounce | |
e227867f | 214 | * buffer is used. Can be called multiple times to append multiple |
3a5a3927 | 215 | * buffers. |
86db1e29 JA |
216 | */ |
217 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
218 | unsigned int len, gfp_t gfp_mask) | |
219 | { | |
68154e90 | 220 | int reading = rq_data_dir(rq) == READ; |
14417799 | 221 | unsigned long addr = (unsigned long) kbuf; |
68154e90 | 222 | int do_copy = 0; |
86db1e29 | 223 | struct bio *bio; |
3a5a3927 | 224 | int ret; |
86db1e29 | 225 | |
ae03bf63 | 226 | if (len > (queue_max_hw_sectors(q) << 9)) |
86db1e29 JA |
227 | return -EINVAL; |
228 | if (!len || !kbuf) | |
229 | return -EINVAL; | |
230 | ||
14417799 | 231 | do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf); |
68154e90 FT |
232 | if (do_copy) |
233 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
234 | else | |
235 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
236 | ||
86db1e29 JA |
237 | if (IS_ERR(bio)) |
238 | return PTR_ERR(bio); | |
239 | ||
aebf526b CH |
240 | bio->bi_opf &= ~REQ_OP_MASK; |
241 | bio->bi_opf |= req_op(rq); | |
86db1e29 | 242 | |
68154e90 | 243 | if (do_copy) |
e8064021 | 244 | rq->rq_flags |= RQF_COPY_USER; |
68154e90 | 245 | |
98d61d5b | 246 | ret = blk_rq_append_bio(rq, bio); |
3a5a3927 JB |
247 | if (unlikely(ret)) { |
248 | /* request is too big */ | |
249 | bio_put(bio); | |
250 | return ret; | |
251 | } | |
252 | ||
86db1e29 JA |
253 | return 0; |
254 | } | |
86db1e29 | 255 | EXPORT_SYMBOL(blk_rq_map_kern); |