arm,arm64: do not always merge biovec if we are running on Xen

This is similar to what it is done on X86: biovecs are prevented from merging
otherwise every dma requests would be forced to bounce on the swiotlb buffer.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>


Changes in v7:
- remove the extra autotranslate check in biomerge.c.

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 1d12f89140ba..c163287b9871 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -22,11 +22,14 @@
 #ifdef __KERNEL__
 
 #include <linux/types.h>
+#include <linux/blk_types.h>
 
 #include <asm/byteorder.h>
 #include <asm/barrier.h>
 #include <asm/pgtable.h>
 
+#include <xen/xen.h>
+
 /*
  * Generic IO read/write.  These perform native-endian accesses.
  */
@@ -263,5 +266,11 @@ extern int devmem_is_allowed(unsigned long pfn);
  */
 #define xlate_dev_kmem_ptr(p)   p
 
+extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
+                                      const struct bio_vec *vec2);
+#define BIOVEC_PHYS_MERGEABLE(vec1, vec2)                               \
+        (__BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&                         \
+         (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2)))
+
 #endif  /* __KERNEL__ */
 #endif  /* __ASM_IO_H */