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
12static void
13xfs_flush_bdev_async_endio(
14	struct bio	*bio)
15{
16	complete(bio->bi_private);
17}
18
19/*
20 * Submit a request for an async cache flush to run. If the request queue does
21 * not require flush operations, just skip it altogether. If the caller needs
22 * to wait for the flush completion at a later point in time, they must supply a
23 * valid completion. This will be signalled when the flush completes.  The
24 * caller never sees the bio that is issued here.
25 */
26void
27xfs_flush_bdev_async(
28	struct bio		*bio,
29	struct block_device	*bdev,
30	struct completion	*done)
31{
32	struct request_queue	*q = bdev->bd_disk->queue;
33
34	if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
35		complete(done);
36		return;
37	}
38
39	bio_init(bio, NULL, 0);
40	bio_set_dev(bio, bdev);
41	bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
42	bio->bi_private = done;
43	bio->bi_end_io = xfs_flush_bdev_async_endio;
44
45	submit_bio(bio);
46}
47int
48xfs_rw_bdev(
49	struct block_device	*bdev,
50	sector_t		sector,
51	unsigned int		count,
52	char			*data,
53	unsigned int		op)
54
55{
56	unsigned int		is_vmalloc = is_vmalloc_addr(data);
57	unsigned int		left = count;
58	int			error;
59	struct bio		*bio;
60
61	if (is_vmalloc && op == REQ_OP_WRITE)
62		flush_kernel_vmap_range(data, count);
63
64	bio = bio_alloc(GFP_KERNEL, bio_max_vecs(left));
65	bio_set_dev(bio, bdev);
66	bio->bi_iter.bi_sector = sector;
67	bio->bi_opf = op | REQ_META | REQ_SYNC;
68
69	do {
70		struct page	*page = kmem_to_page(data);
71		unsigned int	off = offset_in_page(data);
72		unsigned int	len = min_t(unsigned, left, PAGE_SIZE - off);
73
74		while (bio_add_page(bio, page, len, off) != len) {
75			struct bio	*prev = bio;
76
77			bio = bio_alloc(GFP_KERNEL, bio_max_vecs(left));
78			bio_copy_dev(bio, prev);
79			bio->bi_iter.bi_sector = bio_end_sector(prev);
80			bio->bi_opf = prev->bi_opf;
81			bio_chain(prev, bio);
82
83			submit_bio(prev);
84		}
85
86		data += len;
87		left -= len;
88	} while (left > 0);
89
90	error = submit_bio_wait(bio);
91	bio_put(bio);
92
93	if (is_vmalloc && op == REQ_OP_READ)
94		invalidate_kernel_vmap_range(data, count);
95	return error;
96}