1// SPDX-License-Identifier: GPL-2.0
 2/* Maximum size of each resync request */
 3#define RESYNC_BLOCK_SIZE (64*1024)
 4#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
 5
 6/* for managing resync I/O pages */
 7struct resync_pages {
 8	void		*raid_bio;
 9	struct page	*pages[RESYNC_PAGES];
10};
11
12static inline int resync_alloc_pages(struct resync_pages *rp,
13				     gfp_t gfp_flags)
14{
15	int i;
16
17	for (i = 0; i < RESYNC_PAGES; i++) {
18		rp->pages[i] = alloc_page(gfp_flags);
19		if (!rp->pages[i])
20			goto out_free;
21	}
22
23	return 0;
24
25out_free:
26	while (--i >= 0)
27		put_page(rp->pages[i]);
28	return -ENOMEM;
29}
30
31static inline void resync_free_pages(struct resync_pages *rp)
32{
33	int i;
34
35	for (i = 0; i < RESYNC_PAGES; i++)
36		put_page(rp->pages[i]);
37}
38
39static inline void resync_get_all_pages(struct resync_pages *rp)
40{
41	int i;
42
43	for (i = 0; i < RESYNC_PAGES; i++)
44		get_page(rp->pages[i]);
45}
46
47static inline struct page *resync_fetch_page(struct resync_pages *rp,
48					     unsigned idx)
49{
50	if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
51		return NULL;
52	return rp->pages[idx];
53}
54
55/*
56 * 'strct resync_pages' stores actual pages used for doing the resync
57 *  IO, and it is per-bio, so make .bi_private points to it.
58 */
59static inline struct resync_pages *get_resync_pages(struct bio *bio)
60{
61	return bio->bi_private;
62}
63
64/* generally called after bio_reset() for reseting bvec */
65static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
66			       int size)
67{
68	int idx = 0;
69
70	/* initialize bvec table again */
71	do {
72		struct page *page = resync_fetch_page(rp, idx);
73		int len = min_t(int, size, PAGE_SIZE);
74
75		/*
76		 * won't fail because the vec table is big
77		 * enough to hold all these pages
78		 */
79		bio_add_page(bio, page, len, 0);
80		size -= len;
81	} while (idx++ < RESYNC_PAGES && size > 0);
82}