1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (c) 2019 Christoph Hellwig.
 4 */
 5#include "xfs.h"
 6
 7static inline unsigned int bio_max_vecs(unsigned int count)
 8{
 9	return min_t(unsigned, howmany(count, PAGE_SIZE), BIO_MAX_PAGES);
10}
11
12int
13xfs_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}