diff --git a/block/bio.c b/block/bio.c
index 85e243ea6a0e..c34327aa9216 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;
 }
 
@@ -763,8 +757,7 @@ 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
@@ -775,7 +768,7 @@ 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;
@@ -833,7 +826,9 @@ 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);
diff --git a/fs/iomap.c b/fs/iomap.c
index 23ef63fd1669..12654c2e78f8 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -287,7 +287,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	struct iomap_readpage_ctx *ctx = data;
 	struct page *page = ctx->cur_page;
 	struct iomap_page *iop = iomap_page_create(inode, page);
-	bool is_contig = false;
+	bool same_page = false, is_contig = false;
 	loff_t orig_pos = pos;
 	unsigned poff, plen;
 	sector_t sector;
@@ -315,10 +315,14 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	 * Try to merge into a previous segment if we can.
 	 */
 	sector = iomap_sector(iomap, pos);
-	if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
-		if (__bio_try_merge_page(ctx->bio, page, plen, poff, true))
-			goto done;
+	if (ctx->bio && bio_end_sector(ctx->bio) == sector)
 		is_contig = true;
+
+	if (is_contig &&
+	    __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) {
+		if (!same_page && iop)
+			atomic_inc(&iop->read_count);
+		goto done;
 	}
 
 	/*
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index a6f0f4761a37..8da5e6637771 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -758,6 +758,7 @@ xfs_add_to_ioend(
 	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
 	unsigned		len = i_blocksize(inode);
 	unsigned		poff = offset & (PAGE_SIZE - 1);
+	bool			merged, same_page = false;
 	sector_t		sector;
 
 	sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
@@ -774,9 +775,13 @@ xfs_add_to_ioend(
 				wpc->imap.br_state, offset, bdev, sector);
 	}
 
-	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, true)) {
-		if (iop)
-			atomic_inc(&iop->write_count);
+	merged = __bio_try_merge_page(wpc->ioend->io_bio, page, len, poff,
+			&same_page);
+
+	if (iop && !same_page)
+		atomic_inc(&iop->write_count);
+
+	if (!merged) {
 		if (bio_full(wpc->ioend->io_bio))
 			xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
 		bio_add_page(wpc->ioend->io_bio, page, len, poff);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 0f23b5682640..f87abaa898f0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -423,7 +423,7 @@ extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 			   unsigned int, unsigned int);
 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);
 void __bio_add_page(struct bio *bio, struct page *page,
 		unsigned int len, unsigned int off);
 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
