PTR_RET is now PTR_ERR_OR_ZERO

True, it's often used in return statements, but after much bikeshedding
it's probably better to have an explicit name.

(I tried just putting the IS_ERR check inside PTR_ERR itself and gcc
usually generated no more code.  But that clashes current expectations
of how PTR_ERR behaves, so having a separate function is better).

Suggested-by: Julia Lawall <julia.lawall@lip6.fr>
Suggested-by: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

include/linux/err.h

@@ -52,7 +52,7 @@ static inline void * __must_check ERR_CAST(__force const void *ptr)
 	return (void *) ptr;
 }
 
-static inline int __must_check PTR_RET(__force const void *ptr)
+static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
 {
 	if (IS_ERR(ptr))
 		return PTR_ERR(ptr);
@@ -60,6 +60,9 @@ static inline int __must_check PTR_RET(__force const void *ptr)
 		return 0;
 }
 
+/* Deprecated */
+#define PTR_RET(p) PTR_ERR_OR_ZERO(p)
+
 #endif
 
 #endif /* _LINUX_ERR_H */