1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /* Maximum size of each resync request */
3*4882a593Smuzhiyun #define RESYNC_BLOCK_SIZE (64*1024)
4*4882a593Smuzhiyun #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun /*
7*4882a593Smuzhiyun * Number of guaranteed raid bios in case of extreme VM load:
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun #define NR_RAID_BIOS 256
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun /* when we get a read error on a read-only array, we redirect to another
12*4882a593Smuzhiyun * device without failing the first device, or trying to over-write to
13*4882a593Smuzhiyun * correct the read error. To keep track of bad blocks on a per-bio
14*4882a593Smuzhiyun * level, we store IO_BLOCKED in the appropriate 'bios' pointer
15*4882a593Smuzhiyun */
16*4882a593Smuzhiyun #define IO_BLOCKED ((struct bio *)1)
17*4882a593Smuzhiyun /* When we successfully write to a known bad-block, we need to remove the
18*4882a593Smuzhiyun * bad-block marking which must be done from process context. So we record
19*4882a593Smuzhiyun * the success by setting devs[n].bio to IO_MADE_GOOD
20*4882a593Smuzhiyun */
21*4882a593Smuzhiyun #define IO_MADE_GOOD ((struct bio *)2)
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun /* When there are this many requests queue to be written by
26*4882a593Smuzhiyun * the raid thread, we become 'congested' to provide back-pressure
27*4882a593Smuzhiyun * for writeback.
28*4882a593Smuzhiyun */
29*4882a593Smuzhiyun static int max_queued_requests = 1024;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun /* for managing resync I/O pages */
32*4882a593Smuzhiyun struct resync_pages {
33*4882a593Smuzhiyun void *raid_bio;
34*4882a593Smuzhiyun struct page *pages[RESYNC_PAGES];
35*4882a593Smuzhiyun };
36*4882a593Smuzhiyun
rbio_pool_free(void * rbio,void * data)37*4882a593Smuzhiyun static void rbio_pool_free(void *rbio, void *data)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun kfree(rbio);
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun
resync_alloc_pages(struct resync_pages * rp,gfp_t gfp_flags)42*4882a593Smuzhiyun static inline int resync_alloc_pages(struct resync_pages *rp,
43*4882a593Smuzhiyun gfp_t gfp_flags)
44*4882a593Smuzhiyun {
45*4882a593Smuzhiyun int i;
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun for (i = 0; i < RESYNC_PAGES; i++) {
48*4882a593Smuzhiyun rp->pages[i] = alloc_page(gfp_flags);
49*4882a593Smuzhiyun if (!rp->pages[i])
50*4882a593Smuzhiyun goto out_free;
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun return 0;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun out_free:
56*4882a593Smuzhiyun while (--i >= 0)
57*4882a593Smuzhiyun put_page(rp->pages[i]);
58*4882a593Smuzhiyun return -ENOMEM;
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun
resync_free_pages(struct resync_pages * rp)61*4882a593Smuzhiyun static inline void resync_free_pages(struct resync_pages *rp)
62*4882a593Smuzhiyun {
63*4882a593Smuzhiyun int i;
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun for (i = 0; i < RESYNC_PAGES; i++)
66*4882a593Smuzhiyun put_page(rp->pages[i]);
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun
resync_get_all_pages(struct resync_pages * rp)69*4882a593Smuzhiyun static inline void resync_get_all_pages(struct resync_pages *rp)
70*4882a593Smuzhiyun {
71*4882a593Smuzhiyun int i;
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun for (i = 0; i < RESYNC_PAGES; i++)
74*4882a593Smuzhiyun get_page(rp->pages[i]);
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
resync_fetch_page(struct resync_pages * rp,unsigned idx)77*4882a593Smuzhiyun static inline struct page *resync_fetch_page(struct resync_pages *rp,
78*4882a593Smuzhiyun unsigned idx)
79*4882a593Smuzhiyun {
80*4882a593Smuzhiyun if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
81*4882a593Smuzhiyun return NULL;
82*4882a593Smuzhiyun return rp->pages[idx];
83*4882a593Smuzhiyun }
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun /*
86*4882a593Smuzhiyun * 'strct resync_pages' stores actual pages used for doing the resync
87*4882a593Smuzhiyun * IO, and it is per-bio, so make .bi_private points to it.
88*4882a593Smuzhiyun */
get_resync_pages(struct bio * bio)89*4882a593Smuzhiyun static inline struct resync_pages *get_resync_pages(struct bio *bio)
90*4882a593Smuzhiyun {
91*4882a593Smuzhiyun return bio->bi_private;
92*4882a593Smuzhiyun }
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun /* generally called after bio_reset() for reseting bvec */
md_bio_reset_resync_pages(struct bio * bio,struct resync_pages * rp,int size)95*4882a593Smuzhiyun static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
96*4882a593Smuzhiyun int size)
97*4882a593Smuzhiyun {
98*4882a593Smuzhiyun int idx = 0;
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun /* initialize bvec table again */
101*4882a593Smuzhiyun do {
102*4882a593Smuzhiyun struct page *page = resync_fetch_page(rp, idx);
103*4882a593Smuzhiyun int len = min_t(int, size, PAGE_SIZE);
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun /*
106*4882a593Smuzhiyun * won't fail because the vec table is big
107*4882a593Smuzhiyun * enough to hold all these pages
108*4882a593Smuzhiyun */
109*4882a593Smuzhiyun bio_add_page(bio, page, len, 0);
110*4882a593Smuzhiyun size -= len;
111*4882a593Smuzhiyun } while (idx++ < RESYNC_PAGES && size > 0);
112*4882a593Smuzhiyun }
113