block: pass page to xen_biovec_phys_mergeable

xen_biovec_phys_mergeable() only needs .bv_page of the 2nd bio bvec
for checking if the two bvecs can be merged, so pass page to
xen_biovec_phys_mergeable() directly.

No function change.

Cc: ris Ostrovsky <[e-mail]>
Cc: Juergen Gross <[e-mail]>
Cc: [e-mail]
Cc: Omar Sandoval <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Boris Ostrovsky <[e-mail]>
Signed-off-by: Ming Lei <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

block/blk.h

···
 
 	if (addr1 + vec1->bv_len != addr2)
 		return false;
-	if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2))
+	if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page))
 		return false;
 	if ((addr1 | mask) != ((addr2 + vec2->bv_len - 1) | mask))
 		return false;

drivers/xen/biomerge.c

···
 #include <xen/xen.h>
 #include <xen/page.h>
 
+/* check if @page can be merged with 'vec1' */
 bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
-			       const struct bio_vec *vec2)
+			       const struct page *page)
 {
 #if XEN_PAGE_SIZE == PAGE_SIZE
 	unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page));
-	unsigned long bfn2 = pfn_to_bfn(page_to_pfn(vec2->bv_page));
+	unsigned long bfn2 = pfn_to_bfn(page_to_pfn(page));
 
 	return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2;
 #else

include/xen/xen.h

···
 #endif	/* CONFIG_XEN_DOM0 */
 
 struct bio_vec;
+struct page;
+
 bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
-		const struct bio_vec *vec2);
+		const struct page *page);
 
 #if defined(CONFIG_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
 extern u64 xen_saved_max_mem_size;