include/ and checkpatch: prefer __scanf to __attribute__((format(scanf,...)

It's equivalent to __printf, so prefer __scanf.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/compiler-gcc.h

@@ -87,7 +87,8 @@
  */
 #define __pure				__attribute__((pure))
 #define __aligned(x)			__attribute__((aligned(x)))
-#define __printf(a,b)			__attribute__((format(printf,a,b)))
+#define __printf(a, b)			__attribute__((format(printf, a, b)))
+#define __scanf(a, b)			__attribute__((format(scanf, a, b)))
 #define  noinline			__attribute__((noinline))
 #define __attribute_const__		__attribute__((__const__))
 #define __maybe_unused			__attribute__((unused))

include/linux/kernel.h

@@ -328,10 +328,10 @@ extern __printf(2, 3)
 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 
-extern int sscanf(const char *, const char *, ...)
-	__attribute__ ((format (scanf, 2, 3)));
-extern int vsscanf(const char *, const char *, va_list)
-	__attribute__ ((format (scanf, 2, 0)));
+extern __scanf(2, 3)
+int sscanf(const char *, const char *, ...);
+extern __scanf(2, 0)
+int vsscanf(const char *, const char *, va_list);
 
 extern int get_option(char **str, int *pint);
 extern char *get_options(const char *str, int nints, int *ints);

include/xen/xenbus.h

@@ -139,9 +139,9 @@ int xenbus_transaction_start(struct xenbus_transaction *t);
 int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 
 /* Single read and scanf: returns -errno or num scanned if > 0. */
+__scanf(4, 5)
 int xenbus_scanf(struct xenbus_transaction t,
-		 const char *dir, const char *node, const char *fmt, ...)
-	__attribute__((format(scanf, 4, 5)));
+		 const char *dir, const char *node, const char *fmt, ...);
 
 /* Single printf and write: returns -errno or 0. */
 __printf(4, 5)

scripts/checkpatch.pl

@@ -3123,6 +3123,12 @@ sub process {
 			     "__printf(string-index, first-to-check) is preferred over __attribute__((format(printf, string-index, first-to-check)))\n" . $herecurr);
 		}
 
+# Check for __attribute__ format(scanf, prefer __scanf
+		if ($line =~ /\b__attribute__\s*\(\s*\(\s*format\s*\(\s*scanf\b/) {
+			WARN("PREFER_SCANF",
+			     "__scanf(string-index, first-to-check) is preferred over __attribute__((format(scanf, string-index, first-to-check)))\n" . $herecurr);
+		}
+
 # check for sizeof(&)
 		if ($line =~ /\bsizeof\s*\(\s*\&/) {
 			WARN("SIZEOF_ADDRESS",