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 /*
7  * Number of guaranteed raid bios in case of extreme VM load:
8  */
9 #define	NR_RAID_BIOS 256
10 
11 /* when we get a read error on a read-only array, we redirect to another
12  * device without failing the first device, or trying to over-write to
13  * correct the read error.  To keep track of bad blocks on a per-bio
14  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
15  */
16 #define IO_BLOCKED ((struct bio *)1)
17 /* When we successfully write to a known bad-block, we need to remove the
18  * bad-block marking which must be done from process context.  So we record
19  * the success by setting devs[n].bio to IO_MADE_GOOD
20  */
21 #define IO_MADE_GOOD ((struct bio *)2)
22 
23 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
24 
25 /* for managing resync I/O pages */
26 struct resync_pages {
27 	void		*raid_bio;
28 	struct page	*pages[RESYNC_PAGES];
29 };
30 
31 struct raid1_plug_cb {
32 	struct blk_plug_cb	cb;
33 	struct bio_list		pending;
34 };
35 
rbio_pool_free(void * rbio,void * data)36 static void rbio_pool_free(void *rbio, void *data)
37 {
38 	kfree(rbio);
39 }
40 
resync_alloc_pages(struct resync_pages * rp,gfp_t gfp_flags)41 static inline int resync_alloc_pages(struct resync_pages *rp,
42 				     gfp_t gfp_flags)
43 {
44 	int i;
45 
46 	for (i = 0; i < RESYNC_PAGES; i++) {
47 		rp->pages[i] = alloc_page(gfp_flags);
48 		if (!rp->pages[i])
49 			goto out_free;
50 	}
51 
52 	return 0;
53 
54 out_free:
55 	while (--i >= 0)
56 		put_page(rp->pages[i]);
57 	return -ENOMEM;
58 }
59 
resync_free_pages(struct resync_pages * rp)60 static inline void resync_free_pages(struct resync_pages *rp)
61 {
62 	int i;
63 
64 	for (i = 0; i < RESYNC_PAGES; i++)
65 		put_page(rp->pages[i]);
66 }
67 
resync_get_all_pages(struct resync_pages * rp)68 static inline void resync_get_all_pages(struct resync_pages *rp)
69 {
70 	int i;
71 
72 	for (i = 0; i < RESYNC_PAGES; i++)
73 		get_page(rp->pages[i]);
74 }
75 
resync_fetch_page(struct resync_pages * rp,unsigned idx)76 static inline struct page *resync_fetch_page(struct resync_pages *rp,
77 					     unsigned idx)
78 {
79 	if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
80 		return NULL;
81 	return rp->pages[idx];
82 }
83 
84 /*
85  * 'strct resync_pages' stores actual pages used for doing the resync
86  *  IO, and it is per-bio, so make .bi_private points to it.
87  */
get_resync_pages(struct bio * bio)88 static inline struct resync_pages *get_resync_pages(struct bio *bio)
89 {
90 	return bio->bi_private;
91 }
92 
93 /* generally called after bio_reset() for reseting bvec */
md_bio_reset_resync_pages(struct bio * bio,struct resync_pages * rp,int size)94 static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
95 			       int size)
96 {
97 	int idx = 0;
98 
99 	/* initialize bvec table again */
100 	do {
101 		struct page *page = resync_fetch_page(rp, idx);
102 		int len = min_t(int, size, PAGE_SIZE);
103 
104 		/*
105 		 * won't fail because the vec table is big
106 		 * enough to hold all these pages
107 		 */
108 		bio_add_page(bio, page, len, 0);
109 		size -= len;
110 	} while (idx++ < RESYNC_PAGES && size > 0);
111 }
112