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