[PATCH 2/2] string: support overriding strchr/strrchr/strstr macros

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Architecture code may want to override these functions, e.g.
in the case that they are overridden due to use of libfuzzer.

Add #ifndefs to support that and move up the architecture-specific
header, so the overrides may work.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 include/linux/string.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index 4aa11555a005..3b8775c9a57d 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -6,6 +6,10 @@
 #include <linux/types.h>	/* for size_t */
 #include <linux/stddef.h>	/* for NULL */
 #include <linux/overflow.h>	/* for array_size */
+/*
+ * Include machine specific inline routines
+ */
+#include <asm/string.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -16,27 +20,28 @@ extern char * strsep(char **,const char *);
 extern __kernel_size_t strspn(const char *,const char *);
 
 
+#ifndef strchr
 #define strchr(s, c) ({ \
 	(typeof(&(s)[0]))(_strchr((s), c)); \
 	})
+#endif
 
+#ifndef strrchr
 #define strrchr(s, c) ({ \
 	(typeof(&(s)[0]))(_strrchr((s), c)); \
 	})
+#endif
 
+#ifndef strstr
 #define strstr(s1, s2) ({ \
 	(typeof(&(s1)[0]))(_strstr((s1), (s2))); \
 	})
+#endif
 
 #ifndef __HAVE_ARCH_STRCHRNUL
 extern char * strchrnul(const char *,int);
 #endif
 
-/*
- * Include machine specific inline routines
- */
-#include <asm/string.h>
-
 #ifndef __HAVE_ARCH_STRCPY
 extern char * strcpy(char *,const char *);
 #endif
-- 
2.39.5