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>

2 files changed, 20 insertions, 7 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 9ddf25c21538..e2f41b051b12 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -121,6 +121,7 @@ extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
         __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)));
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index b025864d2e43..cbab1df150cf 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -851,23 +851,35 @@ EXPORT_SYMBOL(sscanf);
 
 
 /* Simplified asprintf. */
-char *kasprintf(gfp_t gfp, const char *fmt, ...)
+char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
 {
-        va_list ap;
         unsigned int len;
         char *p;
+        va_list aq;
 
-        va_start(ap, fmt);
-        len = vsnprintf(NULL, 0, fmt, ap);
-        va_end(ap);
+        va_copy(aq, ap);
+        len = vsnprintf(NULL, 0, fmt, aq);
+        va_end(aq);
 
         p = kmalloc(len+1, gfp);
         if (!p)
                 return NULL;
-        va_start(ap, fmt);
+
         vsnprintf(p, len+1, fmt, ap);
-        va_end(ap);
+
         return p;
 }
+EXPORT_SYMBOL(kvasprintf);
+
+char *kasprintf(gfp_t gfp, const char *fmt, ...)
+{
+        va_list ap;
+        char *p;
 
+        va_start(ap, fmt);
+        p = kvasprintf(gfp, fmt, ap);
+        va_end(ap);
+
+        return p;
+}
 EXPORT_SYMBOL(kasprintf);