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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 <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_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(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_iter.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, const 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 /*
208 * Keep going so we check length of all segments
209 */
210 if (uaddr & queue_dma_alignment(q))
211 unaligned = 1;
212 }
213
214 if (unaligned || (q->dma_pad_mask & len) || map_data)
215 bio = bio_copy_user_iov(q, map_data, iov, iov_count, read,
216 gfp_mask);
217 else
218 bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask);
219
220 if (IS_ERR(bio))
221 return PTR_ERR(bio);
222
223 if (bio->bi_iter.bi_size != len) {
224 /*
225 * Grab an extra reference to this bio, as bio_unmap_user()
226 * expects to be able to drop it twice as it happens on the
227 * normal IO completion path
228 */
229 bio_get(bio);
230 bio_endio(bio, 0);
231 __blk_rq_unmap_user(bio);
232 return -EINVAL;
233 }
234
235 if (!bio_flagged(bio, BIO_USER_MAPPED))
236 rq->cmd_flags |= REQ_COPY_USER;
237
238 blk_queue_bounce(q, &bio);
239 bio_get(bio);
240 blk_rq_bio_prep(q, rq, bio);
241 rq->buffer = NULL;
242 return 0;
243}
244EXPORT_SYMBOL(blk_rq_map_user_iov);
245
246/**
247 * blk_rq_unmap_user - unmap a request with user data
248 * @bio: start of bio list
249 *
250 * Description:
251 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
252 * supply the original rq->bio from the blk_rq_map_user() return, since
253 * the I/O completion may have changed rq->bio.
254 */
255int blk_rq_unmap_user(struct bio *bio)
256{
257 struct bio *mapped_bio;
258 int ret = 0, ret2;
259
260 while (bio) {
261 mapped_bio = bio;
262 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
263 mapped_bio = bio->bi_private;
264
265 ret2 = __blk_rq_unmap_user(mapped_bio);
266 if (ret2 && !ret)
267 ret = ret2;
268
269 mapped_bio = bio;
270 bio = bio->bi_next;
271 bio_put(mapped_bio);
272 }
273
274 return ret;
275}
276EXPORT_SYMBOL(blk_rq_unmap_user);
277
278/**
279 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
280 * @q: request queue where request should be inserted
281 * @rq: request to fill
282 * @kbuf: the kernel buffer
283 * @len: length of user data
284 * @gfp_mask: memory allocation flags
285 *
286 * Description:
287 * Data will be mapped directly if possible. Otherwise a bounce
288 * buffer is used. Can be called multiple times to append multiple
289 * buffers.
290 */
291int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
292 unsigned int len, gfp_t gfp_mask)
293{
294 int reading = rq_data_dir(rq) == READ;
295 unsigned long addr = (unsigned long) kbuf;
296 int do_copy = 0;
297 struct bio *bio;
298 int ret;
299
300 if (len > (queue_max_hw_sectors(q) << 9))
301 return -EINVAL;
302 if (!len || !kbuf)
303 return -EINVAL;
304
305 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
306 if (do_copy)
307 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
308 else
309 bio = bio_map_kern(q, kbuf, len, gfp_mask);
310
311 if (IS_ERR(bio))
312 return PTR_ERR(bio);
313
314 if (!reading)
315 bio->bi_rw |= REQ_WRITE;
316
317 if (do_copy)
318 rq->cmd_flags |= REQ_COPY_USER;
319
320 ret = blk_rq_append_bio(q, rq, bio);
321 if (unlikely(ret)) {
322 /* request is too big */
323 bio_put(bio);
324 return ret;
325 }
326
327 blk_queue_bounce(q, &rq->bio);
328 rq->buffer = NULL;
329 return 0;
330}
331EXPORT_SYMBOL(blk_rq_map_kern);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions related to mapping data to requests
4 */
5#include <linux/kernel.h>
6#include <linux/sched/task_stack.h>
7#include <linux/module.h>
8#include <linux/bio.h>
9#include <linux/blkdev.h>
10#include <linux/uio.h>
11
12#include "blk.h"
13
14struct bio_map_data {
15 bool is_our_pages : 1;
16 bool is_null_mapped : 1;
17 struct iov_iter iter;
18 struct iovec iov[];
19};
20
21static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
22 gfp_t gfp_mask)
23{
24 struct bio_map_data *bmd;
25
26 if (data->nr_segs > UIO_MAXIOV)
27 return NULL;
28
29 bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
30 if (!bmd)
31 return NULL;
32 bmd->iter = *data;
33 if (iter_is_iovec(data)) {
34 memcpy(bmd->iov, iter_iov(data), sizeof(struct iovec) * data->nr_segs);
35 bmd->iter.__iov = bmd->iov;
36 }
37 return bmd;
38}
39
40/**
41 * bio_copy_from_iter - copy all pages from iov_iter to bio
42 * @bio: The &struct bio which describes the I/O as destination
43 * @iter: iov_iter as source
44 *
45 * Copy all pages from iov_iter to bio.
46 * Returns 0 on success, or error on failure.
47 */
48static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
49{
50 struct bio_vec *bvec;
51 struct bvec_iter_all iter_all;
52
53 bio_for_each_segment_all(bvec, bio, iter_all) {
54 ssize_t ret;
55
56 ret = copy_page_from_iter(bvec->bv_page,
57 bvec->bv_offset,
58 bvec->bv_len,
59 iter);
60
61 if (!iov_iter_count(iter))
62 break;
63
64 if (ret < bvec->bv_len)
65 return -EFAULT;
66 }
67
68 return 0;
69}
70
71/**
72 * bio_copy_to_iter - copy all pages from bio to iov_iter
73 * @bio: The &struct bio which describes the I/O as source
74 * @iter: iov_iter as destination
75 *
76 * Copy all pages from bio to iov_iter.
77 * Returns 0 on success, or error on failure.
78 */
79static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
80{
81 struct bio_vec *bvec;
82 struct bvec_iter_all iter_all;
83
84 bio_for_each_segment_all(bvec, bio, iter_all) {
85 ssize_t ret;
86
87 ret = copy_page_to_iter(bvec->bv_page,
88 bvec->bv_offset,
89 bvec->bv_len,
90 &iter);
91
92 if (!iov_iter_count(&iter))
93 break;
94
95 if (ret < bvec->bv_len)
96 return -EFAULT;
97 }
98
99 return 0;
100}
101
102/**
103 * bio_uncopy_user - finish previously mapped bio
104 * @bio: bio being terminated
105 *
106 * Free pages allocated from bio_copy_user_iov() and write back data
107 * to user space in case of a read.
108 */
109static int bio_uncopy_user(struct bio *bio)
110{
111 struct bio_map_data *bmd = bio->bi_private;
112 int ret = 0;
113
114 if (!bmd->is_null_mapped) {
115 /*
116 * if we're in a workqueue, the request is orphaned, so
117 * don't copy into a random user address space, just free
118 * and return -EINTR so user space doesn't expect any data.
119 */
120 if (!current->mm)
121 ret = -EINTR;
122 else if (bio_data_dir(bio) == READ)
123 ret = bio_copy_to_iter(bio, bmd->iter);
124 if (bmd->is_our_pages)
125 bio_free_pages(bio);
126 }
127 kfree(bmd);
128 return ret;
129}
130
131static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data,
132 struct iov_iter *iter, gfp_t gfp_mask)
133{
134 struct bio_map_data *bmd;
135 struct page *page;
136 struct bio *bio;
137 int i = 0, ret;
138 int nr_pages;
139 unsigned int len = iter->count;
140 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
141
142 bmd = bio_alloc_map_data(iter, gfp_mask);
143 if (!bmd)
144 return -ENOMEM;
145
146 /*
147 * We need to do a deep copy of the iov_iter including the iovecs.
148 * The caller provided iov might point to an on-stack or otherwise
149 * shortlived one.
150 */
151 bmd->is_our_pages = !map_data;
152 bmd->is_null_mapped = (map_data && map_data->null_mapped);
153
154 nr_pages = bio_max_segs(DIV_ROUND_UP(offset + len, PAGE_SIZE));
155
156 ret = -ENOMEM;
157 bio = bio_kmalloc(nr_pages, gfp_mask);
158 if (!bio)
159 goto out_bmd;
160 bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, req_op(rq));
161
162 if (map_data) {
163 nr_pages = 1U << map_data->page_order;
164 i = map_data->offset / PAGE_SIZE;
165 }
166 while (len) {
167 unsigned int bytes = PAGE_SIZE;
168
169 bytes -= offset;
170
171 if (bytes > len)
172 bytes = len;
173
174 if (map_data) {
175 if (i == map_data->nr_entries * nr_pages) {
176 ret = -ENOMEM;
177 goto cleanup;
178 }
179
180 page = map_data->pages[i / nr_pages];
181 page += (i % nr_pages);
182
183 i++;
184 } else {
185 page = alloc_page(GFP_NOIO | gfp_mask);
186 if (!page) {
187 ret = -ENOMEM;
188 goto cleanup;
189 }
190 }
191
192 if (bio_add_pc_page(rq->q, bio, page, bytes, offset) < bytes) {
193 if (!map_data)
194 __free_page(page);
195 break;
196 }
197
198 len -= bytes;
199 offset = 0;
200 }
201
202 if (map_data)
203 map_data->offset += bio->bi_iter.bi_size;
204
205 /*
206 * success
207 */
208 if (iov_iter_rw(iter) == WRITE &&
209 (!map_data || !map_data->null_mapped)) {
210 ret = bio_copy_from_iter(bio, iter);
211 if (ret)
212 goto cleanup;
213 } else if (map_data && map_data->from_user) {
214 struct iov_iter iter2 = *iter;
215
216 /* This is the copy-in part of SG_DXFER_TO_FROM_DEV. */
217 iter2.data_source = ITER_SOURCE;
218 ret = bio_copy_from_iter(bio, &iter2);
219 if (ret)
220 goto cleanup;
221 } else {
222 if (bmd->is_our_pages)
223 zero_fill_bio(bio);
224 iov_iter_advance(iter, bio->bi_iter.bi_size);
225 }
226
227 bio->bi_private = bmd;
228
229 ret = blk_rq_append_bio(rq, bio);
230 if (ret)
231 goto cleanup;
232 return 0;
233cleanup:
234 if (!map_data)
235 bio_free_pages(bio);
236 bio_uninit(bio);
237 kfree(bio);
238out_bmd:
239 kfree(bmd);
240 return ret;
241}
242
243static void blk_mq_map_bio_put(struct bio *bio)
244{
245 if (bio->bi_opf & REQ_ALLOC_CACHE) {
246 bio_put(bio);
247 } else {
248 bio_uninit(bio);
249 kfree(bio);
250 }
251}
252
253static struct bio *blk_rq_map_bio_alloc(struct request *rq,
254 unsigned int nr_vecs, gfp_t gfp_mask)
255{
256 struct bio *bio;
257
258 if (rq->cmd_flags & REQ_ALLOC_CACHE && (nr_vecs <= BIO_INLINE_VECS)) {
259 bio = bio_alloc_bioset(NULL, nr_vecs, rq->cmd_flags, gfp_mask,
260 &fs_bio_set);
261 if (!bio)
262 return NULL;
263 } else {
264 bio = bio_kmalloc(nr_vecs, gfp_mask);
265 if (!bio)
266 return NULL;
267 bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs, req_op(rq));
268 }
269 return bio;
270}
271
272static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
273 gfp_t gfp_mask)
274{
275 iov_iter_extraction_t extraction_flags = 0;
276 unsigned int max_sectors = queue_max_hw_sectors(rq->q);
277 unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
278 struct bio *bio;
279 int ret;
280 int j;
281
282 if (!iov_iter_count(iter))
283 return -EINVAL;
284
285 bio = blk_rq_map_bio_alloc(rq, nr_vecs, gfp_mask);
286 if (bio == NULL)
287 return -ENOMEM;
288
289 if (blk_queue_pci_p2pdma(rq->q))
290 extraction_flags |= ITER_ALLOW_P2PDMA;
291 if (iov_iter_extract_will_pin(iter))
292 bio_set_flag(bio, BIO_PAGE_PINNED);
293
294 while (iov_iter_count(iter)) {
295 struct page *stack_pages[UIO_FASTIOV];
296 struct page **pages = stack_pages;
297 ssize_t bytes;
298 size_t offs;
299 int npages;
300
301 if (nr_vecs > ARRAY_SIZE(stack_pages))
302 pages = NULL;
303
304 bytes = iov_iter_extract_pages(iter, &pages, LONG_MAX,
305 nr_vecs, extraction_flags, &offs);
306 if (unlikely(bytes <= 0)) {
307 ret = bytes ? bytes : -EFAULT;
308 goto out_unmap;
309 }
310
311 npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
312
313 if (unlikely(offs & queue_dma_alignment(rq->q)))
314 j = 0;
315 else {
316 for (j = 0; j < npages; j++) {
317 struct page *page = pages[j];
318 unsigned int n = PAGE_SIZE - offs;
319 bool same_page = false;
320
321 if (n > bytes)
322 n = bytes;
323
324 if (!bio_add_hw_page(rq->q, bio, page, n, offs,
325 max_sectors, &same_page))
326 break;
327
328 if (same_page)
329 bio_release_page(bio, page);
330 bytes -= n;
331 offs = 0;
332 }
333 }
334 /*
335 * release the pages we didn't map into the bio, if any
336 */
337 while (j < npages)
338 bio_release_page(bio, pages[j++]);
339 if (pages != stack_pages)
340 kvfree(pages);
341 /* couldn't stuff something into bio? */
342 if (bytes) {
343 iov_iter_revert(iter, bytes);
344 break;
345 }
346 }
347
348 ret = blk_rq_append_bio(rq, bio);
349 if (ret)
350 goto out_unmap;
351 return 0;
352
353 out_unmap:
354 bio_release_pages(bio, false);
355 blk_mq_map_bio_put(bio);
356 return ret;
357}
358
359static void bio_invalidate_vmalloc_pages(struct bio *bio)
360{
361#ifdef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
362 if (bio->bi_private && !op_is_write(bio_op(bio))) {
363 unsigned long i, len = 0;
364
365 for (i = 0; i < bio->bi_vcnt; i++)
366 len += bio->bi_io_vec[i].bv_len;
367 invalidate_kernel_vmap_range(bio->bi_private, len);
368 }
369#endif
370}
371
372static void bio_map_kern_endio(struct bio *bio)
373{
374 bio_invalidate_vmalloc_pages(bio);
375 bio_uninit(bio);
376 kfree(bio);
377}
378
379/**
380 * bio_map_kern - map kernel address into bio
381 * @q: the struct request_queue for the bio
382 * @data: pointer to buffer to map
383 * @len: length in bytes
384 * @gfp_mask: allocation flags for bio allocation
385 *
386 * Map the kernel address into a bio suitable for io to a block
387 * device. Returns an error pointer in case of error.
388 */
389static struct bio *bio_map_kern(struct request_queue *q, void *data,
390 unsigned int len, gfp_t gfp_mask)
391{
392 unsigned long kaddr = (unsigned long)data;
393 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
394 unsigned long start = kaddr >> PAGE_SHIFT;
395 const int nr_pages = end - start;
396 bool is_vmalloc = is_vmalloc_addr(data);
397 struct page *page;
398 int offset, i;
399 struct bio *bio;
400
401 bio = bio_kmalloc(nr_pages, gfp_mask);
402 if (!bio)
403 return ERR_PTR(-ENOMEM);
404 bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0);
405
406 if (is_vmalloc) {
407 flush_kernel_vmap_range(data, len);
408 bio->bi_private = data;
409 }
410
411 offset = offset_in_page(kaddr);
412 for (i = 0; i < nr_pages; i++) {
413 unsigned int bytes = PAGE_SIZE - offset;
414
415 if (len <= 0)
416 break;
417
418 if (bytes > len)
419 bytes = len;
420
421 if (!is_vmalloc)
422 page = virt_to_page(data);
423 else
424 page = vmalloc_to_page(data);
425 if (bio_add_pc_page(q, bio, page, bytes,
426 offset) < bytes) {
427 /* we don't support partial mappings */
428 bio_uninit(bio);
429 kfree(bio);
430 return ERR_PTR(-EINVAL);
431 }
432
433 data += bytes;
434 len -= bytes;
435 offset = 0;
436 }
437
438 bio->bi_end_io = bio_map_kern_endio;
439 return bio;
440}
441
442static void bio_copy_kern_endio(struct bio *bio)
443{
444 bio_free_pages(bio);
445 bio_uninit(bio);
446 kfree(bio);
447}
448
449static void bio_copy_kern_endio_read(struct bio *bio)
450{
451 char *p = bio->bi_private;
452 struct bio_vec *bvec;
453 struct bvec_iter_all iter_all;
454
455 bio_for_each_segment_all(bvec, bio, iter_all) {
456 memcpy_from_bvec(p, bvec);
457 p += bvec->bv_len;
458 }
459
460 bio_copy_kern_endio(bio);
461}
462
463/**
464 * bio_copy_kern - copy kernel address into bio
465 * @q: the struct request_queue for the bio
466 * @data: pointer to buffer to copy
467 * @len: length in bytes
468 * @gfp_mask: allocation flags for bio and page allocation
469 * @reading: data direction is READ
470 *
471 * copy the kernel address into a bio suitable for io to a block
472 * device. Returns an error pointer in case of error.
473 */
474static struct bio *bio_copy_kern(struct request_queue *q, void *data,
475 unsigned int len, gfp_t gfp_mask, int reading)
476{
477 unsigned long kaddr = (unsigned long)data;
478 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
479 unsigned long start = kaddr >> PAGE_SHIFT;
480 struct bio *bio;
481 void *p = data;
482 int nr_pages = 0;
483
484 /*
485 * Overflow, abort
486 */
487 if (end < start)
488 return ERR_PTR(-EINVAL);
489
490 nr_pages = end - start;
491 bio = bio_kmalloc(nr_pages, gfp_mask);
492 if (!bio)
493 return ERR_PTR(-ENOMEM);
494 bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0);
495
496 while (len) {
497 struct page *page;
498 unsigned int bytes = PAGE_SIZE;
499
500 if (bytes > len)
501 bytes = len;
502
503 page = alloc_page(GFP_NOIO | __GFP_ZERO | gfp_mask);
504 if (!page)
505 goto cleanup;
506
507 if (!reading)
508 memcpy(page_address(page), p, bytes);
509
510 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
511 break;
512
513 len -= bytes;
514 p += bytes;
515 }
516
517 if (reading) {
518 bio->bi_end_io = bio_copy_kern_endio_read;
519 bio->bi_private = data;
520 } else {
521 bio->bi_end_io = bio_copy_kern_endio;
522 }
523
524 return bio;
525
526cleanup:
527 bio_free_pages(bio);
528 bio_uninit(bio);
529 kfree(bio);
530 return ERR_PTR(-ENOMEM);
531}
532
533/*
534 * Append a bio to a passthrough request. Only works if the bio can be merged
535 * into the request based on the driver constraints.
536 */
537int blk_rq_append_bio(struct request *rq, struct bio *bio)
538{
539 struct bvec_iter iter;
540 struct bio_vec bv;
541 unsigned int nr_segs = 0;
542
543 bio_for_each_bvec(bv, bio, iter)
544 nr_segs++;
545
546 if (!rq->bio) {
547 blk_rq_bio_prep(rq, bio, nr_segs);
548 } else {
549 if (!ll_back_merge_fn(rq, bio, nr_segs))
550 return -EINVAL;
551 rq->biotail->bi_next = bio;
552 rq->biotail = bio;
553 rq->__data_len += (bio)->bi_iter.bi_size;
554 bio_crypt_free_ctx(bio);
555 }
556
557 return 0;
558}
559EXPORT_SYMBOL(blk_rq_append_bio);
560
561/* Prepare bio for passthrough IO given ITER_BVEC iter */
562static int blk_rq_map_user_bvec(struct request *rq, const struct iov_iter *iter)
563{
564 const struct queue_limits *lim = &rq->q->limits;
565 unsigned int max_bytes = lim->max_hw_sectors << SECTOR_SHIFT;
566 unsigned int nsegs;
567 struct bio *bio;
568 int ret;
569
570 if (!iov_iter_count(iter) || iov_iter_count(iter) > max_bytes)
571 return -EINVAL;
572
573 /* reuse the bvecs from the iterator instead of allocating new ones */
574 bio = blk_rq_map_bio_alloc(rq, 0, GFP_KERNEL);
575 if (!bio)
576 return -ENOMEM;
577 bio_iov_bvec_set(bio, iter);
578
579 /* check that the data layout matches the hardware restrictions */
580 ret = bio_split_rw_at(bio, lim, &nsegs, max_bytes);
581 if (ret) {
582 /* if we would have to split the bio, copy instead */
583 if (ret > 0)
584 ret = -EREMOTEIO;
585 blk_mq_map_bio_put(bio);
586 return ret;
587 }
588
589 blk_rq_bio_prep(rq, bio, nsegs);
590 return 0;
591}
592
593/**
594 * blk_rq_map_user_iov - map user data to a request, for passthrough requests
595 * @q: request queue where request should be inserted
596 * @rq: request to map data to
597 * @map_data: pointer to the rq_map_data holding pages (if necessary)
598 * @iter: iovec iterator
599 * @gfp_mask: memory allocation flags
600 *
601 * Description:
602 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
603 * a kernel bounce buffer is used.
604 *
605 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
606 * still in process context.
607 */
608int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
609 struct rq_map_data *map_data,
610 const struct iov_iter *iter, gfp_t gfp_mask)
611{
612 bool copy = false, map_bvec = false;
613 unsigned long align = blk_lim_dma_alignment_and_pad(&q->limits);
614 struct bio *bio = NULL;
615 struct iov_iter i;
616 int ret = -EINVAL;
617
618 if (map_data)
619 copy = true;
620 else if (blk_queue_may_bounce(q))
621 copy = true;
622 else if (iov_iter_alignment(iter) & align)
623 copy = true;
624 else if (iov_iter_is_bvec(iter))
625 map_bvec = true;
626 else if (!user_backed_iter(iter))
627 copy = true;
628 else if (queue_virt_boundary(q))
629 copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
630
631 if (map_bvec) {
632 ret = blk_rq_map_user_bvec(rq, iter);
633 if (!ret)
634 return 0;
635 if (ret != -EREMOTEIO)
636 goto fail;
637 /* fall back to copying the data on limits mismatches */
638 copy = true;
639 }
640
641 i = *iter;
642 do {
643 if (copy)
644 ret = bio_copy_user_iov(rq, map_data, &i, gfp_mask);
645 else
646 ret = bio_map_user_iov(rq, &i, gfp_mask);
647 if (ret)
648 goto unmap_rq;
649 if (!bio)
650 bio = rq->bio;
651 } while (iov_iter_count(&i));
652
653 return 0;
654
655unmap_rq:
656 blk_rq_unmap_user(bio);
657fail:
658 rq->bio = NULL;
659 return ret;
660}
661EXPORT_SYMBOL(blk_rq_map_user_iov);
662
663int blk_rq_map_user(struct request_queue *q, struct request *rq,
664 struct rq_map_data *map_data, void __user *ubuf,
665 unsigned long len, gfp_t gfp_mask)
666{
667 struct iov_iter i;
668 int ret = import_ubuf(rq_data_dir(rq), ubuf, len, &i);
669
670 if (unlikely(ret < 0))
671 return ret;
672
673 return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
674}
675EXPORT_SYMBOL(blk_rq_map_user);
676
677int blk_rq_map_user_io(struct request *req, struct rq_map_data *map_data,
678 void __user *ubuf, unsigned long buf_len, gfp_t gfp_mask,
679 bool vec, int iov_count, bool check_iter_count, int rw)
680{
681 int ret = 0;
682
683 if (vec) {
684 struct iovec fast_iov[UIO_FASTIOV];
685 struct iovec *iov = fast_iov;
686 struct iov_iter iter;
687
688 ret = import_iovec(rw, ubuf, iov_count ? iov_count : buf_len,
689 UIO_FASTIOV, &iov, &iter);
690 if (ret < 0)
691 return ret;
692
693 if (iov_count) {
694 /* SG_IO howto says that the shorter of the two wins */
695 iov_iter_truncate(&iter, buf_len);
696 if (check_iter_count && !iov_iter_count(&iter)) {
697 kfree(iov);
698 return -EINVAL;
699 }
700 }
701
702 ret = blk_rq_map_user_iov(req->q, req, map_data, &iter,
703 gfp_mask);
704 kfree(iov);
705 } else if (buf_len) {
706 ret = blk_rq_map_user(req->q, req, map_data, ubuf, buf_len,
707 gfp_mask);
708 }
709 return ret;
710}
711EXPORT_SYMBOL(blk_rq_map_user_io);
712
713/**
714 * blk_rq_unmap_user - unmap a request with user data
715 * @bio: start of bio list
716 *
717 * Description:
718 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
719 * supply the original rq->bio from the blk_rq_map_user() return, since
720 * the I/O completion may have changed rq->bio.
721 */
722int blk_rq_unmap_user(struct bio *bio)
723{
724 struct bio *next_bio;
725 int ret = 0, ret2;
726
727 while (bio) {
728 if (bio->bi_private) {
729 ret2 = bio_uncopy_user(bio);
730 if (ret2 && !ret)
731 ret = ret2;
732 } else {
733 bio_release_pages(bio, bio_data_dir(bio) == READ);
734 }
735
736 if (bio_integrity(bio))
737 bio_integrity_unmap_user(bio);
738
739 next_bio = bio;
740 bio = bio->bi_next;
741 blk_mq_map_bio_put(next_bio);
742 }
743
744 return ret;
745}
746EXPORT_SYMBOL(blk_rq_unmap_user);
747
748/**
749 * blk_rq_map_kern - map kernel data to a request, for passthrough requests
750 * @q: request queue where request should be inserted
751 * @rq: request to fill
752 * @kbuf: the kernel buffer
753 * @len: length of user data
754 * @gfp_mask: memory allocation flags
755 *
756 * Description:
757 * Data will be mapped directly if possible. Otherwise a bounce
758 * buffer is used. Can be called multiple times to append multiple
759 * buffers.
760 */
761int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
762 unsigned int len, gfp_t gfp_mask)
763{
764 int reading = rq_data_dir(rq) == READ;
765 unsigned long addr = (unsigned long) kbuf;
766 struct bio *bio;
767 int ret;
768
769 if (len > (queue_max_hw_sectors(q) << 9))
770 return -EINVAL;
771 if (!len || !kbuf)
772 return -EINVAL;
773
774 if (!blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf) ||
775 blk_queue_may_bounce(q))
776 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
777 else
778 bio = bio_map_kern(q, kbuf, len, gfp_mask);
779
780 if (IS_ERR(bio))
781 return PTR_ERR(bio);
782
783 bio->bi_opf &= ~REQ_OP_MASK;
784 bio->bi_opf |= req_op(rq);
785
786 ret = blk_rq_append_bio(rq, bio);
787 if (unlikely(ret)) {
788 bio_uninit(bio);
789 kfree(bio);
790 }
791 return ret;
792}
793EXPORT_SYMBOL(blk_rq_map_kern);