seq_file: Add seq_vprintf function and export it

The existing seq_printf function is rewritten in terms of the new
seq_vprintf which is also exported to modules. This allows GFS2
(and potentially other seq_file users) to have a vprintf based
interface and to avoid an extra copy into a temporary buffer in
some cases.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>

1 files changed, 14 insertions, 4 deletions

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 0cbd0494b79e..14cf9de1dbe1 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -385,15 +385,12 @@ int seq_escape(struct seq_file *m, const char *s, const char *esc)
 }
 EXPORT_SYMBOL(seq_escape);
 
-int seq_printf(struct seq_file *m, const char *f, ...)
+int seq_vprintf(struct seq_file *m, const char *f, va_list args)
 {
-	va_list args;
 	int len;
 
 	if (m->count < m->size) {
-		va_start(args, f);
 		len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
-		va_end(args);
 		if (m->count + len < m->size) {
 			m->count += len;
 			return 0;
@@ -402,6 +399,19 @@ int seq_printf(struct seq_file *m, const char *f, ...)
 	seq_set_overflow(m);
 	return -1;
 }
+EXPORT_SYMBOL(seq_vprintf);
+
+int seq_printf(struct seq_file *m, const char *f, ...)
+{
+	int ret;
+	va_list args;
+
+	va_start(args, f);
+	ret = seq_vprintf(m, f, args);
+	va_end(args);
+
+	return ret;
+}
 EXPORT_SYMBOL(seq_printf);
 
 /**