2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public Licens
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
18 #include <linux/bio.h>
19 #include <linux/blkdev.h>
20 #include <linux/slab.h>
21 #include <linux/kernel.h>
27 [BLK_STS_OK] = { 0, "" },
28 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
29 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
30 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
31 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
32 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
33 [BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
34 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
35 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
36 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
37 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
39 /* device mapper special case, should not leak out: */
40 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
42 /* everything else not covered above: */
43 [BLK_STS_IOERR] = { -EIO, "I/O" },
46 int blk_status_to_errno(blk_status_t status)
48 int idx = (__force int)status;
50 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
52 return blk_errors[idx].err;
55 void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
56 struct bio *src, struct bvec_iter *src_iter)
58 struct bio_vec src_bv, dst_bv;
62 while (src_iter->bi_size && dst_iter->bi_size) {
63 src_bv = bio_iter_iovec(src, *src_iter);
64 dst_bv = bio_iter_iovec(dst, *dst_iter);
66 bytes = min(src_bv.bv_len, dst_bv.bv_len);
68 src_p = kmap_atomic(src_bv.bv_page);
69 dst_p = kmap_atomic(dst_bv.bv_page);
71 memcpy(dst_p + dst_bv.bv_offset,
72 src_p + src_bv.bv_offset,
78 flush_dcache_page(dst_bv.bv_page);
80 bio_advance_iter(src, src_iter, bytes);
81 bio_advance_iter(dst, dst_iter, bytes);
86 * bio_copy_data - copy contents of data buffers from one bio to another
88 * @dst: destination bio
90 * Stops when it reaches the end of either @src or @dst - that is, copies
91 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
93 void bio_copy_data(struct bio *dst, struct bio *src)
95 struct bvec_iter src_iter = src->bi_iter;
96 struct bvec_iter dst_iter = dst->bi_iter;
98 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
101 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
105 struct bvec_iter iter;
107 __bio_for_each_segment(bv, bio, iter, start) {
108 char *data = bvec_kmap_irq(&bv, &flags);
109 memset(data, 0, bv.bv_len);
110 bvec_kunmap_irq(data, &flags);
114 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
117 * most users will be overriding ->bi_bdev with a new target,
118 * so we don't set nor calculate new physical/hw segment counts here
120 bio->bi_bdev = bio_src->bi_bdev;
121 bio_set_flag(bio, BIO_CLONED);
122 bio->bi_opf = bio_src->bi_opf;
123 bio->bi_iter = bio_src->bi_iter;
124 bio->bi_io_vec = bio_src->bi_io_vec;
127 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
131 b = bio_alloc_bioset(gfp_mask, 0, bs);
135 __bio_clone_fast(b, bio);
139 struct bio *bio_split(struct bio *bio, int sectors,
140 gfp_t gfp, struct bio_set *bs)
142 struct bio *split = NULL;
144 BUG_ON(sectors <= 0);
145 BUG_ON(sectors >= bio_sectors(bio));
148 * Discards need a mutable bio_vec to accommodate the payload
149 * required by the DSM TRIM and UNMAP commands.
151 if (bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_SECURE_ERASE)
152 split = bio_clone_bioset(bio, gfp, bs);
154 split = bio_clone_fast(bio, gfp, bs);
159 split->bi_iter.bi_size = sectors << 9;
161 bio_advance(bio, split->bi_iter.bi_size);
166 void bio_free_pages(struct bio *bio)
168 struct bio_vec *bvec;
171 bio_for_each_segment_all(bvec, bio, i)
172 __free_page(bvec->bv_page);
175 int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
180 bio_for_each_segment_all(bv, bio, i) {
181 bv->bv_page = alloc_page(gfp_mask);
183 while (--bv >= bio->bi_io_vec)
184 __free_page(bv->bv_page);
192 void bio_advance(struct bio *bio, unsigned bytes)
194 bio_advance_iter(bio, &bio->bi_iter, bytes);
197 static void bio_free(struct bio *bio)
199 unsigned front_pad = bio->bi_pool ? bio->bi_pool->front_pad : 0;
201 kfree((void *) bio - front_pad);
204 void bio_put(struct bio *bio)
206 if (!bio_flagged(bio, BIO_REFFED))
209 BUG_ON(!atomic_read(&bio->__bi_cnt));
214 if (atomic_dec_and_test(&bio->__bi_cnt))
219 static inline bool bio_remaining_done(struct bio *bio)
222 * If we're not chaining, then ->__bi_remaining is always 1 and
223 * we always end io on the first invocation.
225 if (!bio_flagged(bio, BIO_CHAIN))
228 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
230 if (atomic_dec_and_test(&bio->__bi_remaining)) {
231 bio_clear_flag(bio, BIO_CHAIN);
238 static struct bio *__bio_chain_endio(struct bio *bio)
240 struct bio *parent = bio->bi_private;
242 if (!parent->bi_status)
243 parent->bi_status = bio->bi_status;
248 static void bio_chain_endio(struct bio *bio)
250 bio_endio(__bio_chain_endio(bio));
253 void bio_endio(struct bio *bio)
256 if (!bio_remaining_done(bio))
260 * Need to have a real endio function for chained bios, otherwise
261 * various corner cases will break (like stacking block devices that
262 * save/restore bi_end_io) - however, we want to avoid unbounded
263 * recursion and blowing the stack. Tail call optimization would
264 * handle this, but compiling with frame pointers also disables
265 * gcc's sibling call optimization.
267 if (bio->bi_end_io == bio_chain_endio) {
268 bio = __bio_chain_endio(bio);
276 void bio_reset(struct bio *bio)
278 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
280 memset(bio, 0, BIO_RESET_BYTES);
281 bio->bi_flags = flags;
282 atomic_set(&bio->__bi_remaining, 1);
285 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
287 unsigned front_pad = bs ? bs->front_pad : 0;
291 p = kmalloc(front_pad +
293 nr_iovecs * sizeof(struct bio_vec),
300 bio_init(bio, bio->bi_inline_vecs, nr_iovecs);
306 struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
309 struct bvec_iter iter;
313 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
317 bio->bi_bdev = bio_src->bi_bdev;
318 bio->bi_opf = bio_src->bi_opf;
319 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
320 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
322 switch (bio_op(bio)) {
324 case REQ_OP_SECURE_ERASE:
326 case REQ_OP_WRITE_SAME:
327 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
330 bio_for_each_segment(bv, bio_src, iter)
331 bio->bi_io_vec[bio->bi_vcnt++] = bv;