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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> | |
26e49cfc | 8 | #include <linux/uio.h> |
86db1e29 JA |
9 | |
10 | #include "blk.h" | |
11 | ||
98d61d5b CH |
12 | /* |
13 | * Append a bio to a passthrough request. Only works can be merged into | |
14 | * the request based on the driver constraints. | |
15 | */ | |
16 | int blk_rq_append_bio(struct request *rq, struct bio *bio) | |
86db1e29 | 17 | { |
98d61d5b CH |
18 | if (!rq->bio) { |
19 | blk_rq_bio_prep(rq->q, rq, bio); | |
20 | } else { | |
21 | if (!ll_back_merge_fn(rq->q, rq, bio)) | |
22 | return -EINVAL; | |
23 | ||
86db1e29 JA |
24 | rq->biotail->bi_next = bio; |
25 | rq->biotail = bio; | |
4f024f37 | 26 | rq->__data_len += bio->bi_iter.bi_size; |
86db1e29 | 27 | } |
98d61d5b | 28 | |
86db1e29 JA |
29 | return 0; |
30 | } | |
98d61d5b | 31 | EXPORT_SYMBOL(blk_rq_append_bio); |
86db1e29 JA |
32 | |
33 | static int __blk_rq_unmap_user(struct bio *bio) | |
34 | { | |
35 | int ret = 0; | |
36 | ||
37 | if (bio) { | |
38 | if (bio_flagged(bio, BIO_USER_MAPPED)) | |
39 | bio_unmap_user(bio); | |
40 | else | |
41 | ret = bio_uncopy_user(bio); | |
42 | } | |
43 | ||
44 | return ret; | |
45 | } | |
46 | ||
4d6af73d CH |
47 | static int __blk_rq_map_user_iov(struct request *rq, |
48 | struct rq_map_data *map_data, struct iov_iter *iter, | |
49 | gfp_t gfp_mask, bool copy) | |
50 | { | |
51 | struct request_queue *q = rq->q; | |
52 | struct bio *bio, *orig_bio; | |
53 | int ret; | |
54 | ||
55 | if (copy) | |
56 | bio = bio_copy_user_iov(q, map_data, iter, gfp_mask); | |
57 | else | |
58 | bio = bio_map_user_iov(q, iter, gfp_mask); | |
59 | ||
60 | if (IS_ERR(bio)) | |
61 | return PTR_ERR(bio); | |
62 | ||
63 | if (map_data && map_data->null_mapped) | |
64 | bio_set_flag(bio, BIO_NULL_MAPPED); | |
65 | ||
66 | iov_iter_advance(iter, bio->bi_iter.bi_size); | |
67 | if (map_data) | |
68 | map_data->offset += bio->bi_iter.bi_size; | |
69 | ||
70 | orig_bio = bio; | |
71 | blk_queue_bounce(q, &bio); | |
72 | ||
73 | /* | |
74 | * We link the bounce buffer in and could have to traverse it | |
75 | * later so we have to get a ref to prevent it from being freed | |
76 | */ | |
77 | bio_get(bio); | |
78 | ||
98d61d5b | 79 | ret = blk_rq_append_bio(rq, bio); |
4d6af73d CH |
80 | if (ret) { |
81 | bio_endio(bio); | |
82 | __blk_rq_unmap_user(orig_bio); | |
83 | bio_put(bio); | |
84 | return ret; | |
85 | } | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
86db1e29 | 90 | /** |
710027a4 | 91 | * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
92 | * @q: request queue where request should be inserted |
93 | * @rq: request to map data to | |
152e283f | 94 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
26e49cfc | 95 | * @iter: iovec iterator |
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_iov(struct request_queue *q, struct request *rq, | |
26e49cfc KO |
112 | struct rq_map_data *map_data, |
113 | const struct iov_iter *iter, gfp_t gfp_mask) | |
86db1e29 | 114 | { |
357f435d AV |
115 | bool copy = false; |
116 | unsigned long align = q->dma_pad_mask | queue_dma_alignment(q); | |
4d6af73d CH |
117 | struct bio *bio = NULL; |
118 | struct iov_iter i; | |
119 | int ret; | |
86db1e29 | 120 | |
a0ac402c LT |
121 | if (!iter_is_iovec(iter)) |
122 | goto fail; | |
123 | ||
357f435d AV |
124 | if (map_data) |
125 | copy = true; | |
126 | else if (iov_iter_alignment(iter) & align) | |
127 | copy = true; | |
128 | else if (queue_virt_boundary(q)) | |
129 | copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter); | |
afdc1a78 | 130 | |
4d6af73d CH |
131 | i = *iter; |
132 | do { | |
133 | ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); | |
134 | if (ret) | |
135 | goto unmap_rq; | |
136 | if (!bio) | |
137 | bio = rq->bio; | |
138 | } while (iov_iter_count(&i)); | |
86db1e29 | 139 | |
f18573ab FT |
140 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
141 | rq->cmd_flags |= REQ_COPY_USER; | |
86db1e29 | 142 | return 0; |
4d6af73d CH |
143 | |
144 | unmap_rq: | |
145 | __blk_rq_unmap_user(bio); | |
a0ac402c | 146 | fail: |
4d6af73d CH |
147 | rq->bio = NULL; |
148 | return -EINVAL; | |
86db1e29 | 149 | } |
152e283f | 150 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
86db1e29 | 151 | |
ddad8dd0 CH |
152 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
153 | struct rq_map_data *map_data, void __user *ubuf, | |
154 | unsigned long len, gfp_t gfp_mask) | |
155 | { | |
26e49cfc KO |
156 | struct iovec iov; |
157 | struct iov_iter i; | |
8f7e885a | 158 | int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i); |
ddad8dd0 | 159 | |
8f7e885a AV |
160 | if (unlikely(ret < 0)) |
161 | return ret; | |
ddad8dd0 | 162 | |
26e49cfc | 163 | return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask); |
ddad8dd0 CH |
164 | } |
165 | EXPORT_SYMBOL(blk_rq_map_user); | |
166 | ||
86db1e29 JA |
167 | /** |
168 | * blk_rq_unmap_user - unmap a request with user data | |
169 | * @bio: start of bio list | |
170 | * | |
171 | * Description: | |
172 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
173 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 174 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
175 | */ |
176 | int blk_rq_unmap_user(struct bio *bio) | |
177 | { | |
178 | struct bio *mapped_bio; | |
179 | int ret = 0, ret2; | |
180 | ||
181 | while (bio) { | |
182 | mapped_bio = bio; | |
183 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
184 | mapped_bio = bio->bi_private; | |
185 | ||
186 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
187 | if (ret2 && !ret) | |
188 | ret = ret2; | |
189 | ||
190 | mapped_bio = bio; | |
191 | bio = bio->bi_next; | |
192 | bio_put(mapped_bio); | |
193 | } | |
194 | ||
195 | return ret; | |
196 | } | |
86db1e29 JA |
197 | EXPORT_SYMBOL(blk_rq_unmap_user); |
198 | ||
199 | /** | |
710027a4 | 200 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
201 | * @q: request queue where request should be inserted |
202 | * @rq: request to fill | |
203 | * @kbuf: the kernel buffer | |
204 | * @len: length of user data | |
205 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
206 | * |
207 | * Description: | |
208 | * Data will be mapped directly if possible. Otherwise a bounce | |
e227867f | 209 | * buffer is used. Can be called multiple times to append multiple |
3a5a3927 | 210 | * buffers. |
86db1e29 JA |
211 | */ |
212 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
213 | unsigned int len, gfp_t gfp_mask) | |
214 | { | |
68154e90 | 215 | int reading = rq_data_dir(rq) == READ; |
14417799 | 216 | unsigned long addr = (unsigned long) kbuf; |
68154e90 | 217 | int do_copy = 0; |
86db1e29 | 218 | struct bio *bio; |
3a5a3927 | 219 | int ret; |
86db1e29 | 220 | |
ae03bf63 | 221 | if (len > (queue_max_hw_sectors(q) << 9)) |
86db1e29 JA |
222 | return -EINVAL; |
223 | if (!len || !kbuf) | |
224 | return -EINVAL; | |
225 | ||
14417799 | 226 | do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf); |
68154e90 FT |
227 | if (do_copy) |
228 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
229 | else | |
230 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
231 | ||
86db1e29 JA |
232 | if (IS_ERR(bio)) |
233 | return PTR_ERR(bio); | |
234 | ||
609f6ea1 | 235 | if (!reading) |
95fe6c1a | 236 | bio_set_op_attrs(bio, REQ_OP_WRITE, 0); |
86db1e29 | 237 | |
68154e90 FT |
238 | if (do_copy) |
239 | rq->cmd_flags |= REQ_COPY_USER; | |
240 | ||
98d61d5b | 241 | ret = blk_rq_append_bio(rq, bio); |
3a5a3927 JB |
242 | if (unlikely(ret)) { |
243 | /* request is too big */ | |
244 | bio_put(bio); | |
245 | return ret; | |
246 | } | |
247 | ||
86db1e29 | 248 | blk_queue_bounce(q, &rq->bio); |
86db1e29 JA |
249 | return 0; |
250 | } | |
86db1e29 | 251 | EXPORT_SYMBOL(blk_rq_map_kern); |