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