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-rw-r--r--block/bio.c38
1 files changed, 21 insertions, 17 deletions
diff --git a/block/bio.c b/block/bio.c
index 683cbb40f051..ce797d73bb43 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -636,7 +636,7 @@ 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)
+ bool *same_page)
{
phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
bv->bv_offset + bv->bv_len - 1;
@@ -647,15 +647,9 @@ static inline bool page_is_mergeable(const struct bio_vec *bv,
if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
return false;
- if ((vec_end_addr & PAGE_MASK) != page_addr) {
- if (same_page)
- return false;
- if (pfn_to_page(PFN_DOWN(vec_end_addr)) + 1 != page)
- return false;
- }
-
- WARN_ON_ONCE(same_page && (len + off) > PAGE_SIZE);
-
+ *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;
}
@@ -701,6 +695,7 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
bool put_same_page)
{
struct bio_vec *bvec;
+ bool same_page = false;
/*
* cloned bio must not modify vec list
@@ -729,7 +724,7 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
if (bvec_gap_to_prev(q, bvec, offset))
return 0;
- if (page_is_mergeable(bvec, page, len, offset, false) &&
+ if (page_is_mergeable(bvec, page, len, offset, &same_page) &&
can_add_page_to_seg(q, bvec, page, len, offset)) {
bvec->bv_len += len;
goto done;
@@ -767,8 +762,7 @@ EXPORT_SYMBOL(bio_add_pc_page);
* @page: start page to add
* @len: length of the data to add
* @off: offset of the data relative to @page
- * @same_page: if %true only merge if the new data is in the same physical
- * page as the last segment of the bio.
+ * @same_page: return if the segment has been merged inside the same page
*
* Try to add the data at @page + @off to the last bvec of @bio. This is a
* a useful optimisation for file systems with a block size smaller than the
@@ -779,7 +773,7 @@ EXPORT_SYMBOL(bio_add_pc_page);
* Return %true on success or %false on failure.
*/
bool __bio_try_merge_page(struct bio *bio, struct page *page,
- unsigned int len, unsigned int off, bool same_page)
+ unsigned int len, unsigned int off, bool *same_page)
{
if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
return false;
@@ -837,7 +831,9 @@ EXPORT_SYMBOL_GPL(__bio_add_page);
int bio_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
- if (!__bio_try_merge_page(bio, page, len, offset, false)) {
+ bool same_page = false;
+
+ if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
if (bio_full(bio))
return 0;
__bio_add_page(bio, page, len, offset);
@@ -900,6 +896,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
struct page **pages = (struct page **)bv;
+ bool same_page = false;
ssize_t size, left;
unsigned len, i;
size_t offset;
@@ -920,8 +917,15 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
struct page *page = pages[i];
len = min_t(size_t, PAGE_SIZE - offset, left);
- if (WARN_ON_ONCE(bio_add_page(bio, page, len, offset) != len))
- return -EINVAL;
+
+ if (__bio_try_merge_page(bio, page, len, offset, &same_page)) {
+ if (same_page)
+ put_page(page);
+ } else {
+ if (WARN_ON_ONCE(bio_full(bio)))
+ return -EINVAL;
+ __bio_add_page(bio, page, len, offset);
+ }
offset = 0;
}