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-rw-r--r--drivers/xen/Makefile2
-rw-r--r--drivers/xen/biomerge.c13
2 files changed, 14 insertions, 1 deletions
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index fcaf838f54be..b47f5da674d3 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -1,4 +1,4 @@
-obj-y += grant-table.o features.o events.o manage.o
+obj-y += grant-table.o features.o events.o manage.o biomerge.o
obj-y += xenbus/
nostackp := $(call cc-option, -fno-stack-protector)
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));
+}