tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#define MAX_PLUG_BIO 32
25
26/* for managing resync I/O pages */
27struct resync_pages {
28 void *raid_bio;
29 struct page *pages[RESYNC_PAGES];
30};
31
32struct raid1_plug_cb {
33 struct blk_plug_cb cb;
34 struct bio_list pending;
35 unsigned int count;
36};
37
38static void rbio_pool_free(void *rbio, void *data)
39{
40 kfree(rbio);
41}
42
43static inline int resync_alloc_pages(struct resync_pages *rp,
44 gfp_t gfp_flags)
45{
46 int i;
47
48 for (i = 0; i < RESYNC_PAGES; i++) {
49 rp->pages[i] = alloc_page(gfp_flags);
50 if (!rp->pages[i])
51 goto out_free;
52 }
53
54 return 0;
55
56out_free:
57 while (--i >= 0)
58 put_page(rp->pages[i]);
59 return -ENOMEM;
60}
61
62static inline void resync_free_pages(struct resync_pages *rp)
63{
64 int i;
65
66 for (i = 0; i < RESYNC_PAGES; i++)
67 put_page(rp->pages[i]);
68}
69
70static inline void resync_get_all_pages(struct resync_pages *rp)
71{
72 int i;
73
74 for (i = 0; i < RESYNC_PAGES; i++)
75 get_page(rp->pages[i]);
76}
77
78static inline struct page *resync_fetch_page(struct resync_pages *rp,
79 unsigned idx)
80{
81 if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
82 return NULL;
83 return rp->pages[idx];
84}
85
86/*
87 * 'strct resync_pages' stores actual pages used for doing the resync
88 * IO, and it is per-bio, so make .bi_private points to it.
89 */
90static inline struct resync_pages *get_resync_pages(struct bio *bio)
91{
92 return bio->bi_private;
93}
94
95/* generally called after bio_reset() for reseting bvec */
96static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
97 int size)
98{
99 int idx = 0;
100
101 /* initialize bvec table again */
102 do {
103 struct page *page = resync_fetch_page(rp, idx);
104 int len = min_t(int, size, PAGE_SIZE);
105
106 if (WARN_ON(!bio_add_page(bio, page, len, 0))) {
107 bio->bi_status = BLK_STS_RESOURCE;
108 bio_endio(bio);
109 return;
110 }
111
112 size -= len;
113 } while (idx++ < RESYNC_PAGES && size > 0);
114}
115
116
117static inline void raid1_submit_write(struct bio *bio)
118{
119 struct md_rdev *rdev = (void *)bio->bi_bdev;
120
121 bio->bi_next = NULL;
122 bio_set_dev(bio, rdev->bdev);
123 if (test_bit(Faulty, &rdev->flags))
124 bio_io_error(bio);
125 else if (unlikely(bio_op(bio) == REQ_OP_DISCARD &&
126 !bdev_max_discard_sectors(bio->bi_bdev)))
127 /* Just ignore it */
128 bio_endio(bio);
129 else
130 submit_bio_noacct(bio);
131}
132
133static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
134 blk_plug_cb_fn unplug, int copies)
135{
136 struct raid1_plug_cb *plug = NULL;
137 struct blk_plug_cb *cb;
138
139 /*
140 * If bitmap is not enabled, it's safe to submit the io directly, and
141 * this can get optimal performance.
142 */
143 if (!md_bitmap_enabled(mddev->bitmap)) {
144 raid1_submit_write(bio);
145 return true;
146 }
147
148 cb = blk_check_plugged(unplug, mddev, sizeof(*plug));
149 if (!cb)
150 return false;
151
152 plug = container_of(cb, struct raid1_plug_cb, cb);
153 bio_list_add(&plug->pending, bio);
154 if (++plug->count / MAX_PLUG_BIO >= copies) {
155 list_del(&cb->list);
156 cb->callback(cb, false);
157 }
158
159
160 return true;
161}
162
163/*
164 * current->bio_list will be set under submit_bio() context, in this case bitmap
165 * io will be added to the list and wait for current io submission to finish,
166 * while current io submission must wait for bitmap io to be done. In order to
167 * avoid such deadlock, submit bitmap io asynchronously.
168 */
169static inline void raid1_prepare_flush_writes(struct bitmap *bitmap)
170{
171 if (current->bio_list)
172 md_bitmap_unplug_async(bitmap);
173 else
174 md_bitmap_unplug(bitmap);
175}