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block: check if page is mergeable in one helper

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Now the check for deciding if one page is mergeable to current bvec
becomes a bit complicated, and we need to reuse the code before
adding pc page.

So move the check in one dedicated helper.

No function change.

Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2019-03-17 18:01:07 +08:00 committed by Jens Axboe
parent 5a8ce240d4
commit 5919482e22
1 changed files with 23 additions and 13 deletions
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36
block/bio.c
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@ -647,6 +647,24 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
}
EXPORT_SYMBOL(bio_clone_fast);
static inline bool page_is_mergeable(const struct bio_vec *bv,
struct page *page, unsigned int len, unsigned int off,
bool same_page)
{
phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
bv->bv_offset + bv->bv_len - 1;
phys_addr_t page_addr = page_to_phys(page);
if (vec_end_addr + 1 != page_addr + off)
return false;
if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
return false;
if (same_page && (vec_end_addr & PAGE_MASK) != page_addr)
return false;
return true;
}
/**
* bio_add_pc_page - attempt to add page to passthrough bio
* @q: the target queue
@ -770,20 +788,12 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
if (bio->bi_vcnt > 0) {
struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
bv->bv_offset + bv->bv_len - 1;
phys_addr_t page_addr = page_to_phys(page);
if (vec_end_addr + 1 != page_addr + off)
return false;
if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
return false;
if (same_page && (vec_end_addr & PAGE_MASK) != page_addr)
return false;
bv->bv_len += len;
bio->bi_iter.bi_size += len;
return true;
if (page_is_mergeable(bv, page, len, off, same_page)) {
bv->bv_len += len;
bio->bi_iter.bi_size += len;
return true;
}
}
return false;
}