printk: add generic functions to find KERN_<LEVEL> headers

The current form of a KERN_<LEVEL> is "<.>".

Add printk_get_level and printk_skip_level functions to handle these
formats.

These functions centralize tests of KERN_<LEVEL> so a future modification
can change the KERN_<LEVEL> style and shorten the number of bytes consumed
by these headers.

[akpm@linux-foundation.org: fix build error and warning]
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Wu Fengguang <wfg@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 1bec2f7..6e12e1f 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -24,6 +24,32 @@
  */
 #define KERN_CONT	"<c>"
 
+static inline int printk_get_level(const char *buffer)
+{
+	if (buffer[0] == '<' && buffer[1] && buffer[2] == '>') {
+		switch (buffer[1]) {
+		case '0' ... '7':
+		case 'd':	/* KERN_DEFAULT */
+		case 'c':	/* KERN_CONT */
+			return buffer[1];
+		}
+	}
+	return 0;
+}
+
+static inline const char *printk_skip_level(const char *buffer)
+{
+	if (printk_get_level(buffer)) {
+		switch (buffer[1]) {
+		case '0' ... '7':
+		case 'd':	/* KERN_DEFAULT */
+		case 'c':	/* KERN_CONT */
+			return buffer + 3;
+		}
+	}
+	return buffer;
+}
+
 extern int console_printk[];
 
 #define console_loglevel (console_printk[0])