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// SPDX-License-Identifier: GPL-2.0
/* Maximum size of each resync request */
#define RESYNC_BLOCK_SIZE (64*1024)
#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
/*
* Number of guaranteed raid bios in case of extreme VM load:
*/
#define NR_RAID_BIOS 256
/* when we get a read error on a read-only array, we redirect to another
* device without failing the first device, or trying to over-write to
* correct the read error. To keep track of bad blocks on a per-bio
* level, we store IO_BLOCKED in the appropriate 'bios' pointer
*/
#define IO_BLOCKED ((struct bio *)1)
/* When we successfully write to a known bad-block, we need to remove the
* bad-block marking which must be done from process context. So we record
* the success by setting devs[n].bio to IO_MADE_GOOD
*/
#define IO_MADE_GOOD ((struct bio *)2)
#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
/* When there are this many requests queue to be written by
* the raid thread, we become 'congested' to provide back-pressure
* for writeback.
*/
static int max_queued_requests = 1024;
/* for managing resync I/O pages */
struct resync_pages {
void *raid_bio;
struct page *pages[RESYNC_PAGES];
};
static inline int resync_alloc_pages(struct resync_pages *rp,
gfp_t gfp_flags)
{
int i;
for (i = 0; i < RESYNC_PAGES; i++) {
rp->pages[i] = alloc_page(gfp_flags);
if (!rp->pages[i])
goto out_free;
}
return 0;
out_free:
while (--i >= 0)
put_page(rp->pages[i]);
return -ENOMEM;
}
static inline void resync_free_pages(struct resync_pages *rp)
{
int i;
for (i = 0; i < RESYNC_PAGES; i++)
put_page(rp->pages[i]);
}
static inline void resync_get_all_pages(struct resync_pages *rp)
{
int i;
for (i = 0; i < RESYNC_PAGES; i++)
get_page(rp->pages[i]);
}
static inline struct page *resync_fetch_page(struct resync_pages *rp,
unsigned idx)
{
if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
return NULL;
return rp->pages[idx];
}
/*
* 'strct resync_pages' stores actual pages used for doing the resync
* IO, and it is per-bio, so make .bi_private points to it.
*/
static inline struct resync_pages *get_resync_pages(struct bio *bio)
{
return bio->bi_private;
}
/* generally called after bio_reset() for reseting bvec */
static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
int size)
{
int idx = 0;
/* initialize bvec table again */
do {
struct page *page = resync_fetch_page(rp, idx);
int len = min_t(int, size, PAGE_SIZE);
/*
* won't fail because the vec table is big
* enough to hold all these pages
*/
bio_add_page(bio, page, len, 0);
size -= len;
} while (idx++ < RESYNC_PAGES && size > 0);
}
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