If we pass in an offset which is larger than PAGE_SIZE, then
page_is_mergeable() thinks it's not mergeable with the previous bio_vec,
leading to a large number of bio_vecs being used. Use a slightly more
obvious test that the two pages are compatible with each other.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Fixes: 52d52d1c98a9 ("block: only allow contiguous page structs in a bio_vec")
---
block/bio.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index c63ba04bd629..a9931f23d933 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -740,8 +740,8 @@ 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;
+ size_t bv_end = bv->bv_offset + bv->bv_len;
+ phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;
phys_addr_t page_addr = page_to_phys(page);
if (vec_end_addr + 1 != page_addr + off)
@@ -750,9 +750,9 @@ static inline bool page_is_mergeable(const struct bio_vec *bv,
return false;
*same_page = ((vec_end_addr & PAGE_MASK) == page_addr);
- if (!*same_page && pfn_to_page(PFN_DOWN(vec_end_addr)) + 1 != page)
- return false;
- return true;
+ if (*same_page)
+ return true;
+ return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE);
}
/*
--
2.28.0
