diff mbox

[2/4] drivers/vfio: Rework offsetofend()

Message ID 1399944924-1200-3-git-send-email-gwshan@linux.vnet.ibm.com
State Superseded
Headers show

Commit Message

Gavin Shan May 13, 2014, 1:35 a.m. UTC 
The macro offsetofend() introduces unnecessary temporary variable
"tmp". The patch avoids that and saves a bit memory in stack.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 include/linux/vfio.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
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Patch

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 81022a52..8ec980b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -86,9 +86,8 @@  extern void vfio_unregister_iommu_driver(
  * from user space.  This allows us to easily determine if the provided
  * structure is sized to include various fields.
  */
-#define offsetofend(TYPE, MEMBER) ({				\
-	TYPE tmp;						\
-	offsetof(TYPE, MEMBER) + sizeof(tmp.MEMBER); })		\
+#define offsetofend(TYPE, MEMBER) \
+	(offsetof(TYPE, MEMBER)	+ sizeof(((TYPE *)0)->MEMBER))
 
 /*
  * External user API