1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c
new file mode 100644
index 000000000000..ba6eda4b5143
--- /dev/null
+++ b/drivers/xen/biomerge.c
@@ -0,0 +1,13 @@
+#include <linux/bio.h>
+#include <linux/io.h>
+#include <xen/page.h>
+
+bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
+                               const struct bio_vec *vec2)
+{
+        unsigned long mfn1 = pfn_to_mfn(page_to_pfn(vec1->bv_page));
+        unsigned long mfn2 = pfn_to_mfn(page_to_pfn(vec2->bv_page));
+
+        return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&
+                ((mfn1 == mfn2) || ((mfn1+1) == mfn2));
+}