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-rw-r--r--kernel/drivers/xen/biomerge.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/drivers/xen/biomerge.c b/kernel/drivers/xen/biomerge.c
new file mode 100644
index 000000000..0edb91c0d
--- /dev/null
+++ b/kernel/drivers/xen/biomerge.c
@@ -0,0 +1,15 @@
+#include <linux/bio.h>
+#include <linux/io.h>
+#include <linux/export.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));
+}
+EXPORT_SYMBOL(xen_biovec_phys_mergeable);