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6ad5b325 CH |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (c) 2019 Christoph Hellwig. | |
4 | */ | |
5 | #include "xfs.h" | |
6 | ||
7 | static inline unsigned int bio_max_vecs(unsigned int count) | |
8 | { | |
9 | return min_t(unsigned, howmany(count, PAGE_SIZE), BIO_MAX_PAGES); | |
10 | } | |
11 | ||
12 | int | |
13 | xfs_rw_bdev( | |
14 | struct block_device *bdev, | |
15 | sector_t sector, | |
16 | unsigned int count, | |
17 | char *data, | |
18 | unsigned int op) | |
19 | ||
20 | { | |
21 | unsigned int is_vmalloc = is_vmalloc_addr(data); | |
22 | unsigned int left = count; | |
23 | int error; | |
24 | struct bio *bio; | |
25 | ||
26 | if (is_vmalloc && op == REQ_OP_WRITE) | |
27 | flush_kernel_vmap_range(data, count); | |
28 | ||
29 | bio = bio_alloc(GFP_KERNEL, bio_max_vecs(left)); | |
30 | bio_set_dev(bio, bdev); | |
31 | bio->bi_iter.bi_sector = sector; | |
32 | bio->bi_opf = op | REQ_META | REQ_SYNC; | |
33 | ||
34 | do { | |
35 | struct page *page = kmem_to_page(data); | |
36 | unsigned int off = offset_in_page(data); | |
37 | unsigned int len = min_t(unsigned, left, PAGE_SIZE - off); | |
38 | ||
39 | while (bio_add_page(bio, page, len, off) != len) { | |
40 | struct bio *prev = bio; | |
41 | ||
42 | bio = bio_alloc(GFP_KERNEL, bio_max_vecs(left)); | |
43 | bio_copy_dev(bio, prev); | |
44 | bio->bi_iter.bi_sector = bio_end_sector(prev); | |
45 | bio->bi_opf = prev->bi_opf; | |
46 | bio_chain(bio, prev); | |
47 | ||
48 | submit_bio(prev); | |
49 | } | |
50 | ||
51 | data += len; | |
52 | left -= len; | |
53 | } while (left > 0); | |
54 | ||
55 | error = submit_bio_wait(bio); | |
56 | bio_put(bio); | |
57 | ||
58 | if (is_vmalloc && op == REQ_OP_READ) | |
59 | invalidate_kernel_vmap_range(data, count); | |
60 | return error; | |
61 | } |