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 /* When there are this many requests queue to be written by
26 * the raid thread, we become 'congested' to provide back-pressure
27 * for writeback.
28 */
29 static int max_queued_requests = 1024;
30
31 /* for managing resync I/O pages */
32 struct resync_pages {
33 void *raid_bio;
34 struct page *pages[RESYNC_PAGES];
35 };
36
rbio_pool_free(void * rbio,void * data)37 static void rbio_pool_free(void *rbio, void *data)
38 {
39 kfree(rbio);
40 }
41
resync_alloc_pages(struct resync_pages * rp,gfp_t gfp_flags)42 static inline int resync_alloc_pages(struct resync_pages *rp,
43 gfp_t gfp_flags)
44 {
45 int i;
46
47 for (i = 0; i < RESYNC_PAGES; i++) {
48 rp->pages[i] = alloc_page(gfp_flags);
49 if (!rp->pages[i])
50 goto out_free;
51 }
52
53 return 0;
54
55 out_free:
56 while (--i >= 0)
57 put_page(rp->pages[i]);
58 return -ENOMEM;
59 }
60
resync_free_pages(struct resync_pages * rp)61 static inline void resync_free_pages(struct resync_pages *rp)
62 {
63 int i;
64
65 for (i = 0; i < RESYNC_PAGES; i++)
66 put_page(rp->pages[i]);
67 }
68
resync_get_all_pages(struct resync_pages * rp)69 static inline void resync_get_all_pages(struct resync_pages *rp)
70 {
71 int i;
72
73 for (i = 0; i < RESYNC_PAGES; i++)
74 get_page(rp->pages[i]);
75 }
76
resync_fetch_page(struct resync_pages * rp,unsigned idx)77 static inline struct page *resync_fetch_page(struct resync_pages *rp,
78 unsigned idx)
79 {
80 if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
81 return NULL;
82 return rp->pages[idx];
83 }
84
85 /*
86 * 'strct resync_pages' stores actual pages used for doing the resync
87 * IO, and it is per-bio, so make .bi_private points to it.
88 */
get_resync_pages(struct bio * bio)89 static inline struct resync_pages *get_resync_pages(struct bio *bio)
90 {
91 return bio->bi_private;
92 }
93
94 /* generally called after bio_reset() for reseting bvec */
md_bio_reset_resync_pages(struct bio * bio,struct resync_pages * rp,int size)95 static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
96 int size)
97 {
98 int idx = 0;
99
100 /* initialize bvec table again */
101 do {
102 struct page *page = resync_fetch_page(rp, idx);
103 int len = min_t(int, size, PAGE_SIZE);
104
105 /*
106 * won't fail because the vec table is big
107 * enough to hold all these pages
108 */
109 bio_add_page(bio, page, len, 0);
110 size -= len;
111 } while (idx++ < RESYNC_PAGES && size > 0);
112 }
113