From: Gavin Shan <gwshan@linux.vnet.ibm.com>
Date: Fri, 30 May 2014 17:35:54 +0000 (-0600)
Subject: drivers/vfio: Rework offsetofend()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b13460b92093b29347e99d6c3242e350052b62cd;p=linux-beck.git

drivers/vfio: Rework offsetofend()

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>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 81022a52bc34..8ec980b5e3af 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