1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2019 Christoph Hellwig.
4 */
5 #include "xfs.h"
6
bio_max_vecs(unsigned int count)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
xfs_rw_bdev(struct block_device * bdev,sector_t sector,unsigned int count,char * data,unsigned int op)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(prev, bio);
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 }
62