[RFC] PTR_ERR: return 0 if ptr isn't an error value.

From: Rusty Russell
Date: Sun Jun 02 2013 - 22:32:56 EST

Back in 2011, Uwe Kleine-KÃnig added the nonsensically-named
PTR_RET(), providing a means to avoid if() statements in code (commit

Instead, just make PTR_ERR() return 0 if the pointer isn't an error
value. This is harmless, since PTR_ERR() should have never been
passed a non-error value. And GCC is usually smart enough to remove
the extra test if IS_ERR() has already been called.

My vmlinux text increased by 300 bytes:

text data bss dec hex filename
6029452 491628 2576384 9097464 8ad0f8 vmlinux
6029721 491628 2576384 9097733 8ad205 vmlinux.PTR_ERR

Cc: Uwe Kleine-KÃnig <u.kleine-koenig@xxxxxxxxxxxxxx>
Cc: Thomas Meyer <thomas@xxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

diff --git a/include/linux/err.h b/include/linux/err.h
index f2edce2..621d859 100644
--- a/include/linux/err.h
+++ b/include/linux/err.h
@@ -24,14 +24,16 @@ static inline void * __must_check ERR_PTR(long error)
return (void *) error;

-static inline long __must_check PTR_ERR(const void *ptr)
+static inline long __must_check IS_ERR(const void *ptr)
- return (long) ptr;
+ return IS_ERR_VALUE((unsigned long)ptr);

-static inline long __must_check IS_ERR(const void *ptr)
+static inline long __must_check PTR_ERR(const void *ptr)
- return IS_ERR_VALUE((unsigned long)ptr);
+ if (IS_ERR(ptr))
+ return (long) ptr;
+ return 0;

static inline long __must_check IS_ERR_OR_NULL(const void *ptr)
@@ -52,14 +54,7 @@ static inline void * __must_check ERR_CAST(const void *ptr)
return (void *) ptr;

-static inline int __must_check PTR_RET(const void *ptr)
- if (IS_ERR(ptr))
- return PTR_ERR(ptr);
- else
- return 0;
+#define PTR_RET PTR_ERR

#endif /* _LINUX_ERR_H */
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/