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 | ||
12 | int blk_rq_append_bio(struct request_queue *q, struct request *rq, | |
13 | struct bio *bio) | |
14 | { | |
15 | if (!rq->bio) | |
16 | blk_rq_bio_prep(q, rq, bio); | |
17 | else if (!ll_back_merge_fn(q, rq, bio)) | |
18 | return -EINVAL; | |
19 | else { | |
20 | rq->biotail->bi_next = bio; | |
21 | rq->biotail = bio; | |
22 | ||
4f024f37 | 23 | rq->__data_len += bio->bi_iter.bi_size; |
86db1e29 JA |
24 | } |
25 | return 0; | |
26 | } | |
86db1e29 JA |
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 | ||
86db1e29 | 42 | /** |
710027a4 | 43 | * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
44 | * @q: request queue where request should be inserted |
45 | * @rq: request to map data to | |
152e283f | 46 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
26e49cfc | 47 | * @iter: iovec iterator |
a3bce90e | 48 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
49 | * |
50 | * Description: | |
710027a4 | 51 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
52 | * a kernel bounce buffer is used. |
53 | * | |
710027a4 | 54 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
55 | * still in process context. |
56 | * | |
57 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
58 | * before being submitted to the device, as pages mapped may be out of | |
59 | * reach. It's the callers responsibility to make sure this happens. The | |
60 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
61 | * unmapping. | |
62 | */ | |
63 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
26e49cfc KO |
64 | struct rq_map_data *map_data, |
65 | const struct iov_iter *iter, gfp_t gfp_mask) | |
86db1e29 JA |
66 | { |
67 | struct bio *bio; | |
afdc1a78 | 68 | int unaligned = 0; |
26e49cfc KO |
69 | struct iov_iter i; |
70 | struct iovec iov; | |
86db1e29 | 71 | |
26e49cfc | 72 | if (!iter || !iter->count) |
86db1e29 JA |
73 | return -EINVAL; |
74 | ||
26e49cfc KO |
75 | iov_for_each(iov, i, *iter) { |
76 | unsigned long uaddr = (unsigned long) iov.iov_base; | |
afdc1a78 | 77 | |
26e49cfc | 78 | if (!iov.iov_len) |
54787556 XF |
79 | return -EINVAL; |
80 | ||
6b76106d BH |
81 | /* |
82 | * Keep going so we check length of all segments | |
83 | */ | |
84 | if (uaddr & queue_dma_alignment(q)) | |
afdc1a78 | 85 | unaligned = 1; |
afdc1a78 FT |
86 | } |
87 | ||
26e49cfc KO |
88 | if (unaligned || (q->dma_pad_mask & iter->count) || map_data) |
89 | bio = bio_copy_user_iov(q, map_data, iter, gfp_mask); | |
afdc1a78 | 90 | else |
37f19e57 | 91 | bio = bio_map_user_iov(q, iter, gfp_mask); |
afdc1a78 | 92 | |
86db1e29 JA |
93 | if (IS_ERR(bio)) |
94 | return PTR_ERR(bio); | |
95 | ||
a0763b27 CH |
96 | if (map_data && map_data->null_mapped) |
97 | bio->bi_flags |= (1 << BIO_NULL_MAPPED); | |
98 | ||
26e49cfc | 99 | if (bio->bi_iter.bi_size != iter->count) { |
c26156b2 JA |
100 | /* |
101 | * Grab an extra reference to this bio, as bio_unmap_user() | |
102 | * expects to be able to drop it twice as it happens on the | |
103 | * normal IO completion path | |
104 | */ | |
105 | bio_get(bio); | |
86db1e29 | 106 | bio_endio(bio, 0); |
53cc0b29 | 107 | __blk_rq_unmap_user(bio); |
86db1e29 JA |
108 | return -EINVAL; |
109 | } | |
110 | ||
f18573ab FT |
111 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
112 | rq->cmd_flags |= REQ_COPY_USER; | |
113 | ||
07359fc6 | 114 | blk_queue_bounce(q, &bio); |
86db1e29 JA |
115 | bio_get(bio); |
116 | blk_rq_bio_prep(q, rq, bio); | |
86db1e29 JA |
117 | return 0; |
118 | } | |
152e283f | 119 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
86db1e29 | 120 | |
ddad8dd0 CH |
121 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
122 | struct rq_map_data *map_data, void __user *ubuf, | |
123 | unsigned long len, gfp_t gfp_mask) | |
124 | { | |
26e49cfc KO |
125 | struct iovec iov; |
126 | struct iov_iter i; | |
8f7e885a | 127 | int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i); |
ddad8dd0 | 128 | |
8f7e885a AV |
129 | if (unlikely(ret < 0)) |
130 | return ret; | |
ddad8dd0 | 131 | |
26e49cfc | 132 | return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask); |
ddad8dd0 CH |
133 | } |
134 | EXPORT_SYMBOL(blk_rq_map_user); | |
135 | ||
86db1e29 JA |
136 | /** |
137 | * blk_rq_unmap_user - unmap a request with user data | |
138 | * @bio: start of bio list | |
139 | * | |
140 | * Description: | |
141 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
142 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 143 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
144 | */ |
145 | int blk_rq_unmap_user(struct bio *bio) | |
146 | { | |
147 | struct bio *mapped_bio; | |
148 | int ret = 0, ret2; | |
149 | ||
150 | while (bio) { | |
151 | mapped_bio = bio; | |
152 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
153 | mapped_bio = bio->bi_private; | |
154 | ||
155 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
156 | if (ret2 && !ret) | |
157 | ret = ret2; | |
158 | ||
159 | mapped_bio = bio; | |
160 | bio = bio->bi_next; | |
161 | bio_put(mapped_bio); | |
162 | } | |
163 | ||
164 | return ret; | |
165 | } | |
86db1e29 JA |
166 | EXPORT_SYMBOL(blk_rq_unmap_user); |
167 | ||
168 | /** | |
710027a4 | 169 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
170 | * @q: request queue where request should be inserted |
171 | * @rq: request to fill | |
172 | * @kbuf: the kernel buffer | |
173 | * @len: length of user data | |
174 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
175 | * |
176 | * Description: | |
177 | * Data will be mapped directly if possible. Otherwise a bounce | |
e227867f | 178 | * buffer is used. Can be called multiple times to append multiple |
3a5a3927 | 179 | * buffers. |
86db1e29 JA |
180 | */ |
181 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
182 | unsigned int len, gfp_t gfp_mask) | |
183 | { | |
68154e90 | 184 | int reading = rq_data_dir(rq) == READ; |
14417799 | 185 | unsigned long addr = (unsigned long) kbuf; |
68154e90 | 186 | int do_copy = 0; |
86db1e29 | 187 | struct bio *bio; |
3a5a3927 | 188 | int ret; |
86db1e29 | 189 | |
ae03bf63 | 190 | if (len > (queue_max_hw_sectors(q) << 9)) |
86db1e29 JA |
191 | return -EINVAL; |
192 | if (!len || !kbuf) | |
193 | return -EINVAL; | |
194 | ||
14417799 | 195 | do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf); |
68154e90 FT |
196 | if (do_copy) |
197 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
198 | else | |
199 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
200 | ||
86db1e29 JA |
201 | if (IS_ERR(bio)) |
202 | return PTR_ERR(bio); | |
203 | ||
609f6ea1 | 204 | if (!reading) |
a45dc2d2 | 205 | bio->bi_rw |= REQ_WRITE; |
86db1e29 | 206 | |
68154e90 FT |
207 | if (do_copy) |
208 | rq->cmd_flags |= REQ_COPY_USER; | |
209 | ||
3a5a3927 JB |
210 | ret = blk_rq_append_bio(q, rq, bio); |
211 | if (unlikely(ret)) { | |
212 | /* request is too big */ | |
213 | bio_put(bio); | |
214 | return ret; | |
215 | } | |
216 | ||
86db1e29 | 217 | blk_queue_bounce(q, &rq->bio); |
86db1e29 JA |
218 | return 0; |
219 | } | |
86db1e29 | 220 | EXPORT_SYMBOL(blk_rq_map_kern); |