Add kvasprintf()

Add a kvasprintf() function to complement kasprintf().

No in-tree users yet, but I have some coming up.

[akpm@linux-foundation.org: EXPORT it]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Keir Fraser <keir@xensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 9ddf25c..e2f41b0 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -121,6 +121,7 @@
 	__attribute__ ((format (printf, 3, 0)));
 extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
+extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 
 extern int sscanf(const char *, const char *, ...)
 	__attribute__ ((format (scanf, 2, 3)));