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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2020-08-17 20:52:06 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-03 11:26:54 +0200 |
| commit | 2295664518c381ca422e95f2ca3a23f4bd06a711 (patch) | |
| tree | 29602a8e30e3a053929ffec5bc53c90602fbd154 | |
| parent | 3e9eb1e893ba5a71d472be4a34644526b366a536 (diff) | |
| download | linux-stable-2295664518c381ca422e95f2ca3a23f4bd06a711.tar.gz linux-stable-2295664518c381ca422e95f2ca3a23f4bd06a711.tar.bz2 linux-stable-2295664518c381ca422e95f2ca3a23f4bd06a711.zip | |
block: Fix page_is_mergeable() for compound pages
[ Upstream commit d81665198b83e55a28339d1f3e4890ed8a434556 ]
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.
Fixes: 52d52d1c98a9 ("block: only allow contiguous page structs in a bio_vec")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | block/bio.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/block/bio.c b/block/bio.c index 94d697217887..87505a93bcff 100644 --- a/block/bio.c +++ b/block/bio.c @@ -683,8 +683,8 @@ 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) @@ -693,9 +693,9 @@ 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); } static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio, |