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> | |
afdc1a78 | 8 | #include <scsi/sg.h> /* for struct sg_iovec */ |
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) |
86db1e29 JA |
47 | * @iov: pointer to the iovec |
48 | * @iov_count: number of elements in the iovec | |
49 | * @len: I/O byte count | |
a3bce90e | 50 | * @gfp_mask: memory allocation flags |
86db1e29 JA |
51 | * |
52 | * Description: | |
710027a4 | 53 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
86db1e29 JA |
54 | * a kernel bounce buffer is used. |
55 | * | |
710027a4 | 56 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
86db1e29 JA |
57 | * still in process context. |
58 | * | |
59 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() | |
60 | * before being submitted to the device, as pages mapped may be out of | |
61 | * reach. It's the callers responsibility to make sure this happens. The | |
62 | * original bio must be passed back in to blk_rq_unmap_user() for proper | |
63 | * unmapping. | |
64 | */ | |
65 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, | |
86d564c8 | 66 | struct rq_map_data *map_data, const struct sg_iovec *iov, |
152e283f | 67 | int iov_count, unsigned int len, gfp_t gfp_mask) |
86db1e29 JA |
68 | { |
69 | struct bio *bio; | |
afdc1a78 FT |
70 | int i, read = rq_data_dir(rq) == READ; |
71 | int unaligned = 0; | |
86db1e29 JA |
72 | |
73 | if (!iov || iov_count <= 0) | |
74 | return -EINVAL; | |
75 | ||
afdc1a78 FT |
76 | for (i = 0; i < iov_count; i++) { |
77 | unsigned long uaddr = (unsigned long)iov[i].iov_base; | |
78 | ||
54787556 XF |
79 | if (!iov[i].iov_len) |
80 | return -EINVAL; | |
81 | ||
6b76106d BH |
82 | /* |
83 | * Keep going so we check length of all segments | |
84 | */ | |
85 | if (uaddr & queue_dma_alignment(q)) | |
afdc1a78 | 86 | unaligned = 1; |
afdc1a78 FT |
87 | } |
88 | ||
152e283f FT |
89 | if (unaligned || (q->dma_pad_mask & len) || map_data) |
90 | bio = bio_copy_user_iov(q, map_data, iov, iov_count, read, | |
91 | gfp_mask); | |
afdc1a78 | 92 | else |
a3bce90e | 93 | bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask); |
afdc1a78 | 94 | |
86db1e29 JA |
95 | if (IS_ERR(bio)) |
96 | return PTR_ERR(bio); | |
97 | ||
4f024f37 | 98 | if (bio->bi_iter.bi_size != len) { |
c26156b2 JA |
99 | /* |
100 | * Grab an extra reference to this bio, as bio_unmap_user() | |
101 | * expects to be able to drop it twice as it happens on the | |
102 | * normal IO completion path | |
103 | */ | |
104 | bio_get(bio); | |
86db1e29 | 105 | bio_endio(bio, 0); |
53cc0b29 | 106 | __blk_rq_unmap_user(bio); |
86db1e29 JA |
107 | return -EINVAL; |
108 | } | |
109 | ||
f18573ab FT |
110 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
111 | rq->cmd_flags |= REQ_COPY_USER; | |
112 | ||
07359fc6 | 113 | blk_queue_bounce(q, &bio); |
86db1e29 JA |
114 | bio_get(bio); |
115 | blk_rq_bio_prep(q, rq, bio); | |
86db1e29 JA |
116 | return 0; |
117 | } | |
152e283f | 118 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
86db1e29 | 119 | |
ddad8dd0 CH |
120 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
121 | struct rq_map_data *map_data, void __user *ubuf, | |
122 | unsigned long len, gfp_t gfp_mask) | |
123 | { | |
124 | struct sg_iovec iov; | |
125 | ||
126 | iov.iov_base = (void __user *)ubuf; | |
127 | iov.iov_len = len; | |
128 | ||
129 | return blk_rq_map_user_iov(q, rq, map_data, &iov, 1, len, gfp_mask); | |
130 | } | |
131 | EXPORT_SYMBOL(blk_rq_map_user); | |
132 | ||
86db1e29 JA |
133 | /** |
134 | * blk_rq_unmap_user - unmap a request with user data | |
135 | * @bio: start of bio list | |
136 | * | |
137 | * Description: | |
138 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must | |
139 | * supply the original rq->bio from the blk_rq_map_user() return, since | |
710027a4 | 140 | * the I/O completion may have changed rq->bio. |
86db1e29 JA |
141 | */ |
142 | int blk_rq_unmap_user(struct bio *bio) | |
143 | { | |
144 | struct bio *mapped_bio; | |
145 | int ret = 0, ret2; | |
146 | ||
147 | while (bio) { | |
148 | mapped_bio = bio; | |
149 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) | |
150 | mapped_bio = bio->bi_private; | |
151 | ||
152 | ret2 = __blk_rq_unmap_user(mapped_bio); | |
153 | if (ret2 && !ret) | |
154 | ret = ret2; | |
155 | ||
156 | mapped_bio = bio; | |
157 | bio = bio->bi_next; | |
158 | bio_put(mapped_bio); | |
159 | } | |
160 | ||
161 | return ret; | |
162 | } | |
86db1e29 JA |
163 | EXPORT_SYMBOL(blk_rq_unmap_user); |
164 | ||
165 | /** | |
710027a4 | 166 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
86db1e29 JA |
167 | * @q: request queue where request should be inserted |
168 | * @rq: request to fill | |
169 | * @kbuf: the kernel buffer | |
170 | * @len: length of user data | |
171 | * @gfp_mask: memory allocation flags | |
68154e90 FT |
172 | * |
173 | * Description: | |
174 | * Data will be mapped directly if possible. Otherwise a bounce | |
e227867f | 175 | * buffer is used. Can be called multiple times to append multiple |
3a5a3927 | 176 | * buffers. |
86db1e29 JA |
177 | */ |
178 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, | |
179 | unsigned int len, gfp_t gfp_mask) | |
180 | { | |
68154e90 | 181 | int reading = rq_data_dir(rq) == READ; |
14417799 | 182 | unsigned long addr = (unsigned long) kbuf; |
68154e90 | 183 | int do_copy = 0; |
86db1e29 | 184 | struct bio *bio; |
3a5a3927 | 185 | int ret; |
86db1e29 | 186 | |
ae03bf63 | 187 | if (len > (queue_max_hw_sectors(q) << 9)) |
86db1e29 JA |
188 | return -EINVAL; |
189 | if (!len || !kbuf) | |
190 | return -EINVAL; | |
191 | ||
14417799 | 192 | do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf); |
68154e90 FT |
193 | if (do_copy) |
194 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); | |
195 | else | |
196 | bio = bio_map_kern(q, kbuf, len, gfp_mask); | |
197 | ||
86db1e29 JA |
198 | if (IS_ERR(bio)) |
199 | return PTR_ERR(bio); | |
200 | ||
609f6ea1 | 201 | if (!reading) |
a45dc2d2 | 202 | bio->bi_rw |= REQ_WRITE; |
86db1e29 | 203 | |
68154e90 FT |
204 | if (do_copy) |
205 | rq->cmd_flags |= REQ_COPY_USER; | |
206 | ||
3a5a3927 JB |
207 | ret = blk_rq_append_bio(q, rq, bio); |
208 | if (unlikely(ret)) { | |
209 | /* request is too big */ | |
210 | bio_put(bio); | |
211 | return ret; | |
212 | } | |
213 | ||
86db1e29 | 214 | blk_queue_bounce(q, &rq->bio); |
86db1e29 JA |
215 | return 0; |
216 | } | |
86db1e29 | 217 | EXPORT_SYMBOL(blk_rq_map_kern); |