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 */
 26struct resync_pages {
 27	void		*raid_bio;
 28	struct page	*pages[RESYNC_PAGES];
 29};
 30
 31struct raid1_plug_cb {
 32	struct blk_plug_cb	cb;
 33	struct bio_list		pending;
 34};
 35
 36static void rbio_pool_free(void *rbio, void *data)
 37{
 38	kfree(rbio);
 39}
 40
 41static 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
 54out_free:
 55	while (--i >= 0)
 56		put_page(rp->pages[i]);
 57	return -ENOMEM;
 58}
 59
 60static 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
 68static 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
 76static 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 */
 88static 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 */
 94static 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}