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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#include <linux/uio.h>
9
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
23 rq->__data_len += bio->bi_iter.bi_size;
24 }
25 return 0;
26}
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_iov(struct request *rq,
43 struct rq_map_data *map_data, struct iov_iter *iter,
44 gfp_t gfp_mask, bool copy)
45{
46 struct request_queue *q = rq->q;
47 struct bio *bio, *orig_bio;
48 int ret;
49
50 if (copy)
51 bio = bio_copy_user_iov(q, map_data, iter, gfp_mask);
52 else
53 bio = bio_map_user_iov(q, iter, gfp_mask);
54
55 if (IS_ERR(bio))
56 return PTR_ERR(bio);
57
58 if (map_data && map_data->null_mapped)
59 bio_set_flag(bio, BIO_NULL_MAPPED);
60
61 iov_iter_advance(iter, bio->bi_iter.bi_size);
62 if (map_data)
63 map_data->offset += bio->bi_iter.bi_size;
64
65 orig_bio = bio;
66 blk_queue_bounce(q, &bio);
67
68 /*
69 * We link the bounce buffer in and could have to traverse it
70 * later so we have to get a ref to prevent it from being freed
71 */
72 bio_get(bio);
73
74 ret = blk_rq_append_bio(q, rq, bio);
75 if (ret) {
76 bio_endio(bio);
77 __blk_rq_unmap_user(orig_bio);
78 bio_put(bio);
79 return ret;
80 }
81
82 return 0;
83}
84
85/**
86 * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
87 * @q: request queue where request should be inserted
88 * @rq: request to map data to
89 * @map_data: pointer to the rq_map_data holding pages (if necessary)
90 * @iter: iovec iterator
91 * @gfp_mask: memory allocation flags
92 *
93 * Description:
94 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
95 * a kernel bounce buffer is used.
96 *
97 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
98 * still in process context.
99 *
100 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
101 * before being submitted to the device, as pages mapped may be out of
102 * reach. It's the callers responsibility to make sure this happens. The
103 * original bio must be passed back in to blk_rq_unmap_user() for proper
104 * unmapping.
105 */
106int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
107 struct rq_map_data *map_data,
108 const struct iov_iter *iter, gfp_t gfp_mask)
109{
110 bool copy = false;
111 unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
112 struct bio *bio = NULL;
113 struct iov_iter i;
114 int ret;
115
116 if (map_data)
117 copy = true;
118 else if (iov_iter_alignment(iter) & align)
119 copy = true;
120 else if (queue_virt_boundary(q))
121 copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
122
123 i = *iter;
124 do {
125 ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy);
126 if (ret)
127 goto unmap_rq;
128 if (!bio)
129 bio = rq->bio;
130 } while (iov_iter_count(&i));
131
132 if (!bio_flagged(bio, BIO_USER_MAPPED))
133 rq->cmd_flags |= REQ_COPY_USER;
134 return 0;
135
136unmap_rq:
137 __blk_rq_unmap_user(bio);
138 rq->bio = NULL;
139 return -EINVAL;
140}
141EXPORT_SYMBOL(blk_rq_map_user_iov);
142
143int 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{
147 struct iovec iov;
148 struct iov_iter i;
149 int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
150
151 if (unlikely(ret < 0))
152 return ret;
153
154 return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
155}
156EXPORT_SYMBOL(blk_rq_map_user);
157
158/**
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
165 * the I/O completion may have changed rq->bio.
166 */
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}
188EXPORT_SYMBOL(blk_rq_unmap_user);
189
190/**
191 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
192 * @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
197 *
198 * Description:
199 * Data will be mapped directly if possible. Otherwise a bounce
200 * buffer is used. Can be called multiple times to append multiple
201 * buffers.
202 */
203int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
204 unsigned int len, gfp_t gfp_mask)
205{
206 int reading = rq_data_dir(rq) == READ;
207 unsigned long addr = (unsigned long) kbuf;
208 int do_copy = 0;
209 struct bio *bio;
210 int ret;
211
212 if (len > (queue_max_hw_sectors(q) << 9))
213 return -EINVAL;
214 if (!len || !kbuf)
215 return -EINVAL;
216
217 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
218 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
223 if (IS_ERR(bio))
224 return PTR_ERR(bio);
225
226 if (!reading)
227 bio->bi_rw |= REQ_WRITE;
228
229 if (do_copy)
230 rq->cmd_flags |= REQ_COPY_USER;
231
232 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
239 blk_queue_bounce(q, &rq->bio);
240 return 0;
241}
242EXPORT_SYMBOL(blk_rq_map_kern);
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#include <scsi/sg.h> /* for struct sg_iovec */
9
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
23 rq->__data_len += bio->bi_size;
24 }
25 return 0;
26}
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 struct rq_map_data *map_data, void __user *ubuf,
44 unsigned int len, gfp_t gfp_mask)
45{
46 unsigned long uaddr;
47 struct bio *bio, *orig_bio;
48 int reading, ret;
49
50 reading = rq_data_dir(rq) == READ;
51
52 /*
53 * if alignment requirement is satisfied, map in user pages for
54 * direct dma. else, set up kernel bounce buffers
55 */
56 uaddr = (unsigned long) ubuf;
57 if (blk_rq_aligned(q, uaddr, len) && !map_data)
58 bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
59 else
60 bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask);
61
62 if (IS_ERR(bio))
63 return PTR_ERR(bio);
64
65 if (map_data && map_data->null_mapped)
66 bio->bi_flags |= (1 << BIO_NULL_MAPPED);
67
68 orig_bio = bio;
69 blk_queue_bounce(q, &bio);
70
71 /*
72 * We link the bounce buffer in and could have to traverse it
73 * later so we have to get a ref to prevent it from being freed
74 */
75 bio_get(bio);
76
77 ret = blk_rq_append_bio(q, rq, bio);
78 if (!ret)
79 return bio->bi_size;
80
81 /* if it was boucned we must call the end io function */
82 bio_endio(bio, 0);
83 __blk_rq_unmap_user(orig_bio);
84 bio_put(bio);
85 return ret;
86}
87
88/**
89 * blk_rq_map_user - map user data to a request, for REQ_TYPE_BLOCK_PC usage
90 * @q: request queue where request should be inserted
91 * @rq: request structure to fill
92 * @map_data: pointer to the rq_map_data holding pages (if necessary)
93 * @ubuf: the user buffer
94 * @len: length of user data
95 * @gfp_mask: memory allocation flags
96 *
97 * Description:
98 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
99 * a kernel bounce buffer is used.
100 *
101 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
102 * still in process context.
103 *
104 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
105 * before being submitted to the device, as pages mapped may be out of
106 * reach. It's the callers responsibility to make sure this happens. The
107 * original bio must be passed back in to blk_rq_unmap_user() for proper
108 * unmapping.
109 */
110int blk_rq_map_user(struct request_queue *q, struct request *rq,
111 struct rq_map_data *map_data, void __user *ubuf,
112 unsigned long len, gfp_t gfp_mask)
113{
114 unsigned long bytes_read = 0;
115 struct bio *bio = NULL;
116 int ret;
117
118 if (len > (queue_max_hw_sectors(q) << 9))
119 return -EINVAL;
120 if (!len)
121 return -EINVAL;
122
123 if (!ubuf && (!map_data || !map_data->null_mapped))
124 return -EINVAL;
125
126 while (bytes_read != len) {
127 unsigned long map_len, end, start;
128
129 map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
130 end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
131 >> PAGE_SHIFT;
132 start = (unsigned long)ubuf >> PAGE_SHIFT;
133
134 /*
135 * A bad offset could cause us to require BIO_MAX_PAGES + 1
136 * pages. If this happens we just lower the requested
137 * mapping len by a page so that we can fit
138 */
139 if (end - start > BIO_MAX_PAGES)
140 map_len -= PAGE_SIZE;
141
142 ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len,
143 gfp_mask);
144 if (ret < 0)
145 goto unmap_rq;
146 if (!bio)
147 bio = rq->bio;
148 bytes_read += ret;
149 ubuf += ret;
150
151 if (map_data)
152 map_data->offset += ret;
153 }
154
155 if (!bio_flagged(bio, BIO_USER_MAPPED))
156 rq->cmd_flags |= REQ_COPY_USER;
157
158 rq->buffer = NULL;
159 return 0;
160unmap_rq:
161 blk_rq_unmap_user(bio);
162 rq->bio = NULL;
163 return ret;
164}
165EXPORT_SYMBOL(blk_rq_map_user);
166
167/**
168 * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
169 * @q: request queue where request should be inserted
170 * @rq: request to map data to
171 * @map_data: pointer to the rq_map_data holding pages (if necessary)
172 * @iov: pointer to the iovec
173 * @iov_count: number of elements in the iovec
174 * @len: I/O byte count
175 * @gfp_mask: memory allocation flags
176 *
177 * Description:
178 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
179 * a kernel bounce buffer is used.
180 *
181 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
182 * still in process context.
183 *
184 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
185 * before being submitted to the device, as pages mapped may be out of
186 * reach. It's the callers responsibility to make sure this happens. The
187 * original bio must be passed back in to blk_rq_unmap_user() for proper
188 * unmapping.
189 */
190int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
191 struct rq_map_data *map_data, struct sg_iovec *iov,
192 int iov_count, unsigned int len, gfp_t gfp_mask)
193{
194 struct bio *bio;
195 int i, read = rq_data_dir(rq) == READ;
196 int unaligned = 0;
197
198 if (!iov || iov_count <= 0)
199 return -EINVAL;
200
201 for (i = 0; i < iov_count; i++) {
202 unsigned long uaddr = (unsigned long)iov[i].iov_base;
203
204 if (!iov[i].iov_len)
205 return -EINVAL;
206
207 if (uaddr & queue_dma_alignment(q)) {
208 unaligned = 1;
209 break;
210 }
211 }
212
213 if (unaligned || (q->dma_pad_mask & len) || map_data)
214 bio = bio_copy_user_iov(q, map_data, iov, iov_count, read,
215 gfp_mask);
216 else
217 bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask);
218
219 if (IS_ERR(bio))
220 return PTR_ERR(bio);
221
222 if (bio->bi_size != len) {
223 /*
224 * Grab an extra reference to this bio, as bio_unmap_user()
225 * expects to be able to drop it twice as it happens on the
226 * normal IO completion path
227 */
228 bio_get(bio);
229 bio_endio(bio, 0);
230 __blk_rq_unmap_user(bio);
231 return -EINVAL;
232 }
233
234 if (!bio_flagged(bio, BIO_USER_MAPPED))
235 rq->cmd_flags |= REQ_COPY_USER;
236
237 blk_queue_bounce(q, &bio);
238 bio_get(bio);
239 blk_rq_bio_prep(q, rq, bio);
240 rq->buffer = NULL;
241 return 0;
242}
243EXPORT_SYMBOL(blk_rq_map_user_iov);
244
245/**
246 * blk_rq_unmap_user - unmap a request with user data
247 * @bio: start of bio list
248 *
249 * Description:
250 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
251 * supply the original rq->bio from the blk_rq_map_user() return, since
252 * the I/O completion may have changed rq->bio.
253 */
254int blk_rq_unmap_user(struct bio *bio)
255{
256 struct bio *mapped_bio;
257 int ret = 0, ret2;
258
259 while (bio) {
260 mapped_bio = bio;
261 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
262 mapped_bio = bio->bi_private;
263
264 ret2 = __blk_rq_unmap_user(mapped_bio);
265 if (ret2 && !ret)
266 ret = ret2;
267
268 mapped_bio = bio;
269 bio = bio->bi_next;
270 bio_put(mapped_bio);
271 }
272
273 return ret;
274}
275EXPORT_SYMBOL(blk_rq_unmap_user);
276
277/**
278 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
279 * @q: request queue where request should be inserted
280 * @rq: request to fill
281 * @kbuf: the kernel buffer
282 * @len: length of user data
283 * @gfp_mask: memory allocation flags
284 *
285 * Description:
286 * Data will be mapped directly if possible. Otherwise a bounce
287 * buffer is used. Can be called multple times to append multple
288 * buffers.
289 */
290int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
291 unsigned int len, gfp_t gfp_mask)
292{
293 int reading = rq_data_dir(rq) == READ;
294 unsigned long addr = (unsigned long) kbuf;
295 int do_copy = 0;
296 struct bio *bio;
297 int ret;
298
299 if (len > (queue_max_hw_sectors(q) << 9))
300 return -EINVAL;
301 if (!len || !kbuf)
302 return -EINVAL;
303
304 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
305 if (do_copy)
306 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
307 else
308 bio = bio_map_kern(q, kbuf, len, gfp_mask);
309
310 if (IS_ERR(bio))
311 return PTR_ERR(bio);
312
313 if (rq_data_dir(rq) == WRITE)
314 bio->bi_rw |= REQ_WRITE;
315
316 if (do_copy)
317 rq->cmd_flags |= REQ_COPY_USER;
318
319 ret = blk_rq_append_bio(q, rq, bio);
320 if (unlikely(ret)) {
321 /* request is too big */
322 bio_put(bio);
323 return ret;
324 }
325
326 blk_queue_bounce(q, &rq->bio);
327 rq->buffer = NULL;
328 return 0;
329}
330EXPORT_SYMBOL(blk_rq_map_kern);