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authorJens Axboe2008-01-29 07:53:40 -0600
committerJens Axboe2008-01-29 14:55:08 -0600
commit86db1e29772372155db08ff48a9ceb76e11a2ad1 (patch)
tree312f38eb3245873c476c50f816b85610fef9615a /block/blk-map.c
parent8324aa91d1e11a1fc25f209687a0b2e6c2ed47d0 (diff)
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block: continue ll_rw_blk.c splitup
Adds files for barrier handling, rq execution, io context handling, mapping data to requests, and queue settings. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-map.c')
-rw-r--r--block/blk-map.c264
1 files changed, 264 insertions, 0 deletions
diff --git a/block/blk-map.c b/block/blk-map.c
new file mode 100644
index 00000000000..916cfc96ffa
--- /dev/null
+++ b/block/blk-map.c
@@ -0,0 +1,264 @@
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>
8
9#include "blk.h"
10
11int blk_rq_append_bio(struct request_queue *q, struct request *rq,
12 struct bio *bio)
13{
14 if (!rq->bio)
15 blk_rq_bio_prep(q, rq, bio);
16 else if (!ll_back_merge_fn(q, rq, bio))
17 return -EINVAL;
18 else {
19 rq->biotail->bi_next = bio;
20 rq->biotail = bio;
21
22 rq->data_len += bio->bi_size;
23 }
24 return 0;
25}
26EXPORT_SYMBOL(blk_rq_append_bio);
27
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
42static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
43 void __user *ubuf, unsigned int len)
44{
45 unsigned long uaddr;
46 struct bio *bio, *orig_bio;
47 int reading, ret;
48
49 reading = rq_data_dir(rq) == READ;
50
51 /*
52 * if alignment requirement is satisfied, map in user pages for
53 * direct dma. else, set up kernel bounce buffers
54 */
55 uaddr = (unsigned long) ubuf;
56 if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
57 bio = bio_map_user(q, NULL, uaddr, len, reading);
58 else
59 bio = bio_copy_user(q, uaddr, len, reading);
60
61 if (IS_ERR(bio))
62 return PTR_ERR(bio);
63
64 orig_bio = bio;
65 blk_queue_bounce(q, &bio);
66
67 /*
68 * We link the bounce buffer in and could have to traverse it
69 * later so we have to get a ref to prevent it from being freed
70 */
71 bio_get(bio);
72
73 ret = blk_rq_append_bio(q, rq, bio);
74 if (!ret)
75 return bio->bi_size;
76
77 /* if it was boucned we must call the end io function */
78 bio_endio(bio, 0);
79 __blk_rq_unmap_user(orig_bio);
80 bio_put(bio);
81 return ret;
82}
83
84/**
85 * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
86 * @q: request queue where request should be inserted
87 * @rq: request structure to fill
88 * @ubuf: the user buffer
89 * @len: length of user data
90 *
91 * Description:
92 * Data will be mapped directly for zero copy io, if possible. Otherwise
93 * a kernel bounce buffer is used.
94 *
95 * A matching blk_rq_unmap_user() must be issued at the end of io, while
96 * still in process context.
97 *
98 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
99 * before being submitted to the device, as pages mapped may be out of
100 * reach. It's the callers responsibility to make sure this happens. The
101 * original bio must be passed back in to blk_rq_unmap_user() for proper
102 * unmapping.
103 */
104int blk_rq_map_user(struct request_queue *q, struct request *rq,
105 void __user *ubuf, unsigned long len)
106{
107 unsigned long bytes_read = 0;
108 struct bio *bio = NULL;
109 int ret;
110
111 if (len > (q->max_hw_sectors << 9))
112 return -EINVAL;
113 if (!len || !ubuf)
114 return -EINVAL;
115
116 while (bytes_read != len) {
117 unsigned long map_len, end, start;
118
119 map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
120 end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
121 >> PAGE_SHIFT;
122 start = (unsigned long)ubuf >> PAGE_SHIFT;
123
124 /*
125 * A bad offset could cause us to require BIO_MAX_PAGES + 1
126 * pages. If this happens we just lower the requested
127 * mapping len by a page so that we can fit
128 */
129 if (end - start > BIO_MAX_PAGES)
130 map_len -= PAGE_SIZE;
131
132 ret = __blk_rq_map_user(q, rq, ubuf, map_len);
133 if (ret < 0)
134 goto unmap_rq;
135 if (!bio)
136 bio = rq->bio;
137 bytes_read += ret;
138 ubuf += ret;
139 }
140
141 rq->buffer = rq->data = NULL;
142 return 0;
143unmap_rq:
144 blk_rq_unmap_user(bio);
145 return ret;
146}
147
148EXPORT_SYMBOL(blk_rq_map_user);
149
150/**
151 * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
152 * @q: request queue where request should be inserted
153 * @rq: request to map data to
154 * @iov: pointer to the iovec
155 * @iov_count: number of elements in the iovec
156 * @len: I/O byte count
157 *
158 * Description:
159 * Data will be mapped directly for zero copy io, if possible. Otherwise
160 * a kernel bounce buffer is used.
161 *
162 * A matching blk_rq_unmap_user() must be issued at the end of io, while
163 * still in process context.
164 *
165 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
166 * before being submitted to the device, as pages mapped may be out of
167 * reach. It's the callers responsibility to make sure this happens. The
168 * original bio must be passed back in to blk_rq_unmap_user() for proper
169 * unmapping.
170 */
171int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
172 struct sg_iovec *iov, int iov_count, unsigned int len)
173{
174 struct bio *bio;
175
176 if (!iov || iov_count <= 0)
177 return -EINVAL;
178
179 /* we don't allow misaligned data like bio_map_user() does. If the
180 * user is using sg, they're expected to know the alignment constraints
181 * and respect them accordingly */
182 bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
183 if (IS_ERR(bio))
184 return PTR_ERR(bio);
185
186 if (bio->bi_size != len) {
187 bio_endio(bio, 0);
188 bio_unmap_user(bio);
189 return -EINVAL;
190 }
191
192 bio_get(bio);
193 blk_rq_bio_prep(q, rq, bio);
194 rq->buffer = rq->data = NULL;
195 return 0;
196}
197
198EXPORT_SYMBOL(blk_rq_map_user_iov);
199
200/**
201 * blk_rq_unmap_user - unmap a request with user data
202 * @bio: start of bio list
203 *
204 * Description:
205 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
206 * supply the original rq->bio from the blk_rq_map_user() return, since
207 * the io completion may have changed rq->bio.
208 */
209int blk_rq_unmap_user(struct bio *bio)
210{
211 struct bio *mapped_bio;
212 int ret = 0, ret2;
213
214 while (bio) {
215 mapped_bio = bio;
216 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
217 mapped_bio = bio->bi_private;
218
219 ret2 = __blk_rq_unmap_user(mapped_bio);
220 if (ret2 && !ret)
221 ret = ret2;
222
223 mapped_bio = bio;
224 bio = bio->bi_next;
225 bio_put(mapped_bio);
226 }
227
228 return ret;
229}
230
231EXPORT_SYMBOL(blk_rq_unmap_user);
232
233/**
234 * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
235 * @q: request queue where request should be inserted
236 * @rq: request to fill
237 * @kbuf: the kernel buffer
238 * @len: length of user data
239 * @gfp_mask: memory allocation flags
240 */
241int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
242 unsigned int len, gfp_t gfp_mask)
243{
244 struct bio *bio;
245
246 if (len > (q->max_hw_sectors << 9))
247 return -EINVAL;
248 if (!len || !kbuf)
249 return -EINVAL;
250
251 bio = bio_map_kern(q, kbuf, len, gfp_mask);
252 if (IS_ERR(bio))
253 return PTR_ERR(bio);
254
255 if (rq_data_dir(rq) == WRITE)
256 bio->bi_rw |= (1 << BIO_RW);
257
258 blk_rq_bio_prep(q, rq, bio);
259 blk_queue_bounce(q, &rq->bio);
260 rq->buffer = rq->data = NULL;
261 return 0;
262}
263
264EXPORT_SYMBOL(blk_rq_map_kern);