blob: b8d2725324a6b88391db4c8a5daf7a9c1309dd86 [file] [log] [blame]
Jens Axboe86db1e22008-01-29 14:53:40 +01001/*
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>
Kent Overstreet26e49cf2015-01-18 16:16:31 +01008#include <linux/uio.h>
Jens Axboe86db1e22008-01-29 14:53:40 +01009
10#include "blk.h"
11
12int 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
Kent Overstreet4f024f32013-10-11 15:44:27 -070023 rq->__data_len += bio->bi_iter.bi_size;
Jens Axboe86db1e22008-01-29 14:53:40 +010024 }
25 return 0;
26}
Jens Axboe86db1e22008-01-29 14:53:40 +010027
28static 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
Jens Axboe86db1e22008-01-29 14:53:40 +010042/**
Randy Dunlap710027a2008-08-19 20:13:11 +020043 * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
Jens Axboe86db1e22008-01-29 14:53:40 +010044 * @q: request queue where request should be inserted
45 * @rq: request to map data to
FUJITA Tomonori152e2832008-08-28 16:17:06 +090046 * @map_data: pointer to the rq_map_data holding pages (if necessary)
Kent Overstreet26e49cf2015-01-18 16:16:31 +010047 * @iter: iovec iterator
FUJITA Tomonoria3bce902008-08-28 16:17:05 +090048 * @gfp_mask: memory allocation flags
Jens Axboe86db1e22008-01-29 14:53:40 +010049 *
50 * Description:
Randy Dunlap710027a2008-08-19 20:13:11 +020051 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
Jens Axboe86db1e22008-01-29 14:53:40 +010052 * a kernel bounce buffer is used.
53 *
Randy Dunlap710027a2008-08-19 20:13:11 +020054 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
Jens Axboe86db1e22008-01-29 14:53:40 +010055 * 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 */
63int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
Kent Overstreet26e49cf2015-01-18 16:16:31 +010064 struct rq_map_data *map_data,
65 const struct iov_iter *iter, gfp_t gfp_mask)
Jens Axboe86db1e22008-01-29 14:53:40 +010066{
67 struct bio *bio;
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020068 int unaligned = 0;
Kent Overstreet26e49cf2015-01-18 16:16:31 +010069 struct iov_iter i;
70 struct iovec iov;
Jens Axboe86db1e22008-01-29 14:53:40 +010071
Kent Overstreet26e49cf2015-01-18 16:16:31 +010072 if (!iter || !iter->count)
Jens Axboe86db1e22008-01-29 14:53:40 +010073 return -EINVAL;
74
Kent Overstreet26e49cf2015-01-18 16:16:31 +010075 iov_for_each(iov, i, *iter) {
76 unsigned long uaddr = (unsigned long) iov.iov_base;
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020077
Kent Overstreet26e49cf2015-01-18 16:16:31 +010078 if (!iov.iov_len)
Xiaotian Feng54787552010-11-29 10:03:55 +010079 return -EINVAL;
80
Ben Hutchings6b761062011-11-13 19:58:09 +010081 /*
82 * Keep going so we check length of all segments
83 */
84 if (uaddr & queue_dma_alignment(q))
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020085 unaligned = 1;
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020086 }
87
Kent Overstreet26e49cf2015-01-18 16:16:31 +010088 if (unaligned || (q->dma_pad_mask & iter->count) || map_data)
89 bio = bio_copy_user_iov(q, map_data, iter, gfp_mask);
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020090 else
Christoph Hellwig37f19e52015-01-18 16:16:33 +010091 bio = bio_map_user_iov(q, iter, gfp_mask);
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020092
Jens Axboe86db1e22008-01-29 14:53:40 +010093 if (IS_ERR(bio))
94 return PTR_ERR(bio);
95
Christoph Hellwiga0763b22015-02-11 14:07:49 +010096 if (map_data && map_data->null_mapped)
97 bio->bi_flags |= (1 << BIO_NULL_MAPPED);
98
Kent Overstreet26e49cf2015-01-18 16:16:31 +010099 if (bio->bi_iter.bi_size != iter->count) {
Jens Axboec26156b2008-11-18 15:07:05 +0100100 /*
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);
Jens Axboe86db1e22008-01-29 14:53:40 +0100106 bio_endio(bio, 0);
Petr Vandrovec53cc0b22008-11-19 11:12:14 +0100107 __blk_rq_unmap_user(bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100108 return -EINVAL;
109 }
110
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200111 if (!bio_flagged(bio, BIO_USER_MAPPED))
112 rq->cmd_flags |= REQ_COPY_USER;
113
FUJITA Tomonori07359fc2008-06-26 19:39:23 +0200114 blk_queue_bounce(q, &bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100115 bio_get(bio);
116 blk_rq_bio_prep(q, rq, bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100117 return 0;
118}
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900119EXPORT_SYMBOL(blk_rq_map_user_iov);
Jens Axboe86db1e22008-01-29 14:53:40 +0100120
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100121int 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{
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100125 struct iovec iov;
126 struct iov_iter i;
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100127
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100128 iov.iov_base = ubuf;
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100129 iov.iov_len = len;
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100130 iov_iter_init(&i, rq_data_dir(rq), &iov, 1, len);
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100131
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100132 return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100133}
134EXPORT_SYMBOL(blk_rq_map_user);
135
Jens Axboe86db1e22008-01-29 14:53:40 +0100136/**
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
Randy Dunlap710027a2008-08-19 20:13:11 +0200143 * the I/O completion may have changed rq->bio.
Jens Axboe86db1e22008-01-29 14:53:40 +0100144 */
145int 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}
Jens Axboe86db1e22008-01-29 14:53:40 +0100166EXPORT_SYMBOL(blk_rq_unmap_user);
167
168/**
Randy Dunlap710027a2008-08-19 20:13:11 +0200169 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
Jens Axboe86db1e22008-01-29 14:53:40 +0100170 * @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
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200175 *
176 * Description:
177 * Data will be mapped directly if possible. Otherwise a bounce
Masanari Iidae2278672014-02-18 22:54:36 +0900178 * buffer is used. Can be called multiple times to append multiple
James Bottomley3a5a3922009-05-17 18:55:18 +0300179 * buffers.
Jens Axboe86db1e22008-01-29 14:53:40 +0100180 */
181int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
182 unsigned int len, gfp_t gfp_mask)
183{
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200184 int reading = rq_data_dir(rq) == READ;
Namhyung Kim14417792010-09-15 13:08:27 +0200185 unsigned long addr = (unsigned long) kbuf;
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200186 int do_copy = 0;
Jens Axboe86db1e22008-01-29 14:53:40 +0100187 struct bio *bio;
James Bottomley3a5a3922009-05-17 18:55:18 +0300188 int ret;
Jens Axboe86db1e22008-01-29 14:53:40 +0100189
Martin K. Petersenae03bf62009-05-22 17:17:50 -0400190 if (len > (queue_max_hw_sectors(q) << 9))
Jens Axboe86db1e22008-01-29 14:53:40 +0100191 return -EINVAL;
192 if (!len || !kbuf)
193 return -EINVAL;
194
Namhyung Kim14417792010-09-15 13:08:27 +0200195 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200196 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
Jens Axboe86db1e22008-01-29 14:53:40 +0100201 if (IS_ERR(bio))
202 return PTR_ERR(bio);
203
majianpeng609f6ea2011-12-21 15:27:24 +0100204 if (!reading)
Benny Halevya45dc2d2010-09-13 21:32:19 +0200205 bio->bi_rw |= REQ_WRITE;
Jens Axboe86db1e22008-01-29 14:53:40 +0100206
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200207 if (do_copy)
208 rq->cmd_flags |= REQ_COPY_USER;
209
James Bottomley3a5a3922009-05-17 18:55:18 +0300210 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
Jens Axboe86db1e22008-01-29 14:53:40 +0100217 blk_queue_bounce(q, &rq->bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100218 return 0;
219}
Jens Axboe86db1e22008-01-29 14:53:40 +0100220EXPORT_SYMBOL(blk_rq_map_kern);