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 bio_max_segs(howmany(count, PAGE_SIZE));
10}
11
12int
13xfs_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