[PATCH] produce a warning on unchecked inode_setattr use

The patch below uses the new-in-gcc-3.4 option to generate a warning on
unchecked results of marked functions, and applies this to the
inode_setattr function (which based on recent bk commits HAS to be checked
for it's return value for correct operation).  A warning looks like this:

fs/ext2/inode.c:1279: warning: ignoring return value of 'inode_setattr', declared with attribute warn_unused_result
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/compiler-gcc+.h

@@ -13,3 +13,4 @@
 #define __attribute_used__	__attribute__((__used__))
 #define __attribute_pure__	__attribute__((pure))
 #define __attribute_const__	__attribute__((__const__))
+#define __must_check 		__attribute__((warn_unused_result))

include/linux/compiler-gcc3.h

@@ -25,3 +25,6 @@
 #if __GNUC_MINOR__ >= 1
 #define  noinline __attribute__((noinline))
 #endif
+#if __GNUC_MINOR__ >= 4
+#define __must_check __attribute__((warn_unused_result))
+#endif

include/linux/compiler.h

@@ -69,6 +69,10 @@ extern void __chk_user_ptr(void __user *);
 # define __deprecated		/* unimplemented */
 #endif
 
+#ifndef __must_check
+#define __must_check
+#endif
+
 /*
  * Allow us to avoid 'defined but not used' warnings on functions and data,
  * as well as force them to be emitted to the assembly file.

include/linux/fs.h

@@ -1521,7 +1521,7 @@ extern int simple_pin_fs(char *name, struct vfsmount **mount, int *count);
 extern void simple_release_fs(struct vfsmount **mount, int *count);
 
 extern int inode_change_ok(struct inode *, struct iattr *);
-extern int inode_setattr(struct inode *, struct iattr *);
+extern int __must_check inode_setattr(struct inode *, struct iattr *);
 
 extern void inode_update_time(struct inode *inode, int ctime_too);