For *scnprintf(), vsnprintf() is always called even if the input size is
0. That is a waste of time, so just return 0 in this case.
Note that vsnprintf() will never return -1 to indicate an error. So
skipping the call to vsnprintf() when size is 0 will have no functional
impact at all.
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
---
lib/vsprintf.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3b8129dd374c..d419154b47bb 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2895,13 +2895,15 @@ int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
{
int i;
+ if (unlikely(!size))
+ return 0;
+
i = vsnprintf(buf, size, fmt, args);
if (likely(i < size))
return i;
- if (size != 0)
- return size - 1;
- return 0;
+
+ return size - 1;
}
EXPORT_SYMBOL(vscnprintf);
--
2.27.0
