1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c
new file mode 100644
index 000000000..05a286d24
--- /dev/null
+++ b/drivers/xen/biomerge.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bio.h>
+#include <linux/export.h>
+#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 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(page));
+
+	return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2;
+#else
+	/*
+	 * XXX: Add support for merging bio_vec when using different page
+	 * size in Xen and Linux.
+	 */
+	return false;
+#endif
+}