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 bio_max_segs(howmany(count, PAGE_SIZE));
10 }
11
12 int
xfs_rw_bdev(struct block_device * bdev,sector_t sector,unsigned int count,char * data,enum req_op op)13 xfs_rw_bdev(
14 struct block_device *bdev,
15 sector_t sector,
16 unsigned int count,
17 char *data,
18 enum req_op 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(bdev, bio_max_vecs(left), op | REQ_META | REQ_SYNC,
30 GFP_KERNEL);
31 bio->bi_iter.bi_sector = sector;
32
33 do {
34 struct page *page = kmem_to_page(data);
35 unsigned int off = offset_in_page(data);
36 unsigned int len = min_t(unsigned, left, PAGE_SIZE - off);
37
38 while (bio_add_page(bio, page, len, off) != len) {
39 struct bio *prev = bio;
40
41 bio = bio_alloc(prev->bi_bdev, bio_max_vecs(left),
42 prev->bi_opf, GFP_KERNEL);
43 bio->bi_iter.bi_sector = bio_end_sector(prev);
44 bio_chain(prev, bio);
45
46 submit_bio(prev);
47 }
48
49 data += len;
50 left -= len;
51 } while (left > 0);
52
53 error = submit_bio_wait(bio);
54 bio_put(bio);
55
56 if (is_vmalloc && op == REQ_OP_READ)
57 invalidate_kernel_vmap_range(data, count);
58 return error;
59 }
60