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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
Sagi Grimberg463484562015-09-03 19:28:23 +030012static bool iovec_gap_to_prv(struct request_queue *q,
13 struct iovec *prv, struct iovec *cur)
14{
15 unsigned long prev_end;
16
17 if (!queue_virt_boundary(q))
18 return false;
19
20 if (prv->iov_base == NULL && prv->iov_len == 0)
21 /* prv is not set - don't check */
22 return false;
23
24 prev_end = (unsigned long)(prv->iov_base + prv->iov_len);
25
26 return (((unsigned long)cur->iov_base & queue_virt_boundary(q)) ||
27 prev_end & queue_virt_boundary(q));
28}
29
Jens Axboe86db1e22008-01-29 14:53:40 +010030int blk_rq_append_bio(struct request_queue *q, struct request *rq,
31 struct bio *bio)
32{
33 if (!rq->bio)
34 blk_rq_bio_prep(q, rq, bio);
35 else if (!ll_back_merge_fn(q, rq, bio))
36 return -EINVAL;
37 else {
38 rq->biotail->bi_next = bio;
39 rq->biotail = bio;
40
Kent Overstreet4f024f32013-10-11 15:44:27 -070041 rq->__data_len += bio->bi_iter.bi_size;
Jens Axboe86db1e22008-01-29 14:53:40 +010042 }
43 return 0;
44}
Jens Axboe86db1e22008-01-29 14:53:40 +010045
46static int __blk_rq_unmap_user(struct bio *bio)
47{
48 int ret = 0;
49
50 if (bio) {
51 if (bio_flagged(bio, BIO_USER_MAPPED))
52 bio_unmap_user(bio);
53 else
54 ret = bio_uncopy_user(bio);
55 }
56
57 return ret;
58}
59
Jens Axboe86db1e22008-01-29 14:53:40 +010060/**
Randy Dunlap710027a2008-08-19 20:13:11 +020061 * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
Jens Axboe86db1e22008-01-29 14:53:40 +010062 * @q: request queue where request should be inserted
63 * @rq: request to map data to
FUJITA Tomonori152e2832008-08-28 16:17:06 +090064 * @map_data: pointer to the rq_map_data holding pages (if necessary)
Kent Overstreet26e49cf2015-01-18 16:16:31 +010065 * @iter: iovec iterator
FUJITA Tomonoria3bce902008-08-28 16:17:05 +090066 * @gfp_mask: memory allocation flags
Jens Axboe86db1e22008-01-29 14:53:40 +010067 *
68 * Description:
Randy Dunlap710027a2008-08-19 20:13:11 +020069 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
Jens Axboe86db1e22008-01-29 14:53:40 +010070 * a kernel bounce buffer is used.
71 *
Randy Dunlap710027a2008-08-19 20:13:11 +020072 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
Jens Axboe86db1e22008-01-29 14:53:40 +010073 * still in process context.
74 *
75 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
76 * before being submitted to the device, as pages mapped may be out of
77 * reach. It's the callers responsibility to make sure this happens. The
78 * original bio must be passed back in to blk_rq_unmap_user() for proper
79 * unmapping.
80 */
81int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
Kent Overstreet26e49cf2015-01-18 16:16:31 +010082 struct rq_map_data *map_data,
83 const struct iov_iter *iter, gfp_t gfp_mask)
Jens Axboe86db1e22008-01-29 14:53:40 +010084{
85 struct bio *bio;
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020086 int unaligned = 0;
Kent Overstreet26e49cf2015-01-18 16:16:31 +010087 struct iov_iter i;
Sagi Grimberg463484562015-09-03 19:28:23 +030088 struct iovec iov, prv = {.iov_base = NULL, .iov_len = 0};
Jens Axboe86db1e22008-01-29 14:53:40 +010089
Kent Overstreet26e49cf2015-01-18 16:16:31 +010090 if (!iter || !iter->count)
Jens Axboe86db1e22008-01-29 14:53:40 +010091 return -EINVAL;
92
Kent Overstreet26e49cf2015-01-18 16:16:31 +010093 iov_for_each(iov, i, *iter) {
94 unsigned long uaddr = (unsigned long) iov.iov_base;
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +020095
Kent Overstreet26e49cf2015-01-18 16:16:31 +010096 if (!iov.iov_len)
Xiaotian Feng54787552010-11-29 10:03:55 +010097 return -EINVAL;
98
Ben Hutchings6b761062011-11-13 19:58:09 +010099 /*
100 * Keep going so we check length of all segments
101 */
Sagi Grimberg463484562015-09-03 19:28:23 +0300102 if ((uaddr & queue_dma_alignment(q)) ||
103 iovec_gap_to_prv(q, &prv, &iov))
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +0200104 unaligned = 1;
Sagi Grimberg463484562015-09-03 19:28:23 +0300105
106 prv.iov_base = iov.iov_base;
107 prv.iov_len = iov.iov_len;
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +0200108 }
109
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100110 if (unaligned || (q->dma_pad_mask & iter->count) || map_data)
111 bio = bio_copy_user_iov(q, map_data, iter, gfp_mask);
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +0200112 else
Christoph Hellwig37f19e52015-01-18 16:16:33 +0100113 bio = bio_map_user_iov(q, iter, gfp_mask);
FUJITA Tomonoriafdc1a72008-04-11 12:56:51 +0200114
Jens Axboe86db1e22008-01-29 14:53:40 +0100115 if (IS_ERR(bio))
116 return PTR_ERR(bio);
117
Christoph Hellwiga0763b22015-02-11 14:07:49 +0100118 if (map_data && map_data->null_mapped)
Jens Axboeb7c44ed2015-07-24 12:37:59 -0600119 bio_set_flag(bio, BIO_NULL_MAPPED);
Christoph Hellwiga0763b22015-02-11 14:07:49 +0100120
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100121 if (bio->bi_iter.bi_size != iter->count) {
Jens Axboec26156b2008-11-18 15:07:05 +0100122 /*
123 * Grab an extra reference to this bio, as bio_unmap_user()
124 * expects to be able to drop it twice as it happens on the
125 * normal IO completion path
126 */
127 bio_get(bio);
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200128 bio_endio(bio);
Petr Vandrovec53cc0b22008-11-19 11:12:14 +0100129 __blk_rq_unmap_user(bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100130 return -EINVAL;
131 }
132
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200133 if (!bio_flagged(bio, BIO_USER_MAPPED))
134 rq->cmd_flags |= REQ_COPY_USER;
135
FUJITA Tomonori07359fc2008-06-26 19:39:23 +0200136 blk_queue_bounce(q, &bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100137 bio_get(bio);
138 blk_rq_bio_prep(q, rq, bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100139 return 0;
140}
FUJITA Tomonori152e2832008-08-28 16:17:06 +0900141EXPORT_SYMBOL(blk_rq_map_user_iov);
Jens Axboe86db1e22008-01-29 14:53:40 +0100142
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100143int blk_rq_map_user(struct request_queue *q, struct request *rq,
144 struct rq_map_data *map_data, void __user *ubuf,
145 unsigned long len, gfp_t gfp_mask)
146{
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100147 struct iovec iov;
148 struct iov_iter i;
Al Viro8f7e8852015-03-21 20:06:04 -0400149 int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100150
Al Viro8f7e8852015-03-21 20:06:04 -0400151 if (unlikely(ret < 0))
152 return ret;
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100153
Kent Overstreet26e49cf2015-01-18 16:16:31 +0100154 return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
Christoph Hellwigddad8dd2015-01-18 16:16:29 +0100155}
156EXPORT_SYMBOL(blk_rq_map_user);
157
Jens Axboe86db1e22008-01-29 14:53:40 +0100158/**
159 * blk_rq_unmap_user - unmap a request with user data
160 * @bio: start of bio list
161 *
162 * Description:
163 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
164 * supply the original rq->bio from the blk_rq_map_user() return, since
Randy Dunlap710027a2008-08-19 20:13:11 +0200165 * the I/O completion may have changed rq->bio.
Jens Axboe86db1e22008-01-29 14:53:40 +0100166 */
167int blk_rq_unmap_user(struct bio *bio)
168{
169 struct bio *mapped_bio;
170 int ret = 0, ret2;
171
172 while (bio) {
173 mapped_bio = bio;
174 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
175 mapped_bio = bio->bi_private;
176
177 ret2 = __blk_rq_unmap_user(mapped_bio);
178 if (ret2 && !ret)
179 ret = ret2;
180
181 mapped_bio = bio;
182 bio = bio->bi_next;
183 bio_put(mapped_bio);
184 }
185
186 return ret;
187}
Jens Axboe86db1e22008-01-29 14:53:40 +0100188EXPORT_SYMBOL(blk_rq_unmap_user);
189
190/**
Randy Dunlap710027a2008-08-19 20:13:11 +0200191 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
Jens Axboe86db1e22008-01-29 14:53:40 +0100192 * @q: request queue where request should be inserted
193 * @rq: request to fill
194 * @kbuf: the kernel buffer
195 * @len: length of user data
196 * @gfp_mask: memory allocation flags
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200197 *
198 * Description:
199 * Data will be mapped directly if possible. Otherwise a bounce
Masanari Iidae2278672014-02-18 22:54:36 +0900200 * buffer is used. Can be called multiple times to append multiple
James Bottomley3a5a3922009-05-17 18:55:18 +0300201 * buffers.
Jens Axboe86db1e22008-01-29 14:53:40 +0100202 */
203int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
204 unsigned int len, gfp_t gfp_mask)
205{
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200206 int reading = rq_data_dir(rq) == READ;
Namhyung Kim14417792010-09-15 13:08:27 +0200207 unsigned long addr = (unsigned long) kbuf;
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200208 int do_copy = 0;
Jens Axboe86db1e22008-01-29 14:53:40 +0100209 struct bio *bio;
James Bottomley3a5a3922009-05-17 18:55:18 +0300210 int ret;
Jens Axboe86db1e22008-01-29 14:53:40 +0100211
Martin K. Petersenae03bf62009-05-22 17:17:50 -0400212 if (len > (queue_max_hw_sectors(q) << 9))
Jens Axboe86db1e22008-01-29 14:53:40 +0100213 return -EINVAL;
214 if (!len || !kbuf)
215 return -EINVAL;
216
Namhyung Kim14417792010-09-15 13:08:27 +0200217 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200218 if (do_copy)
219 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
220 else
221 bio = bio_map_kern(q, kbuf, len, gfp_mask);
222
Jens Axboe86db1e22008-01-29 14:53:40 +0100223 if (IS_ERR(bio))
224 return PTR_ERR(bio);
225
majianpeng609f6ea2011-12-21 15:27:24 +0100226 if (!reading)
Benny Halevya45dc2d2010-09-13 21:32:19 +0200227 bio->bi_rw |= REQ_WRITE;
Jens Axboe86db1e22008-01-29 14:53:40 +0100228
FUJITA Tomonori68154e92008-04-25 12:47:50 +0200229 if (do_copy)
230 rq->cmd_flags |= REQ_COPY_USER;
231
James Bottomley3a5a3922009-05-17 18:55:18 +0300232 ret = blk_rq_append_bio(q, rq, bio);
233 if (unlikely(ret)) {
234 /* request is too big */
235 bio_put(bio);
236 return ret;
237 }
238
Jens Axboe86db1e22008-01-29 14:53:40 +0100239 blk_queue_bounce(q, &rq->bio);
Jens Axboe86db1e22008-01-29 14:53:40 +0100240 return 0;
241}
Jens Axboe86db1e22008-01-29 14:53:40 +0100242EXPORT_SYMBOL(blk_rq_map_kern);