[glibc] stdio-common: Add lock optimization to vfprintf and vfwprintf

[glibc] stdio-common: Add lock optimization to vfprintf and vfwprintf

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=3d0005b54af06d3bb7ab9f85bfe6a27552b11f74

commit 3d0005b54af06d3bb7ab9f85bfe6a27552b11f74
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon Dec 19 18:56:54 2022 +0100

    stdio-common: Add lock optimization to vfprintf and vfwprintf
    
    After the rewrite and the implicit unbuffered streams handling, this
    is very straightforward to add.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 stdio-common/vfprintf-internal.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/stdio-common/vfprintf-internal.c b/stdio-common/vfprintf-internal.c
index 83a6aea510..23ada8d0ff 100644
--- a/stdio-common/vfprintf-internal.c
+++ b/stdio-common/vfprintf-internal.c
@@ -1452,6 +1452,14 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap, unsigned int mode_flags)
     return EOF;
 #endif
 
+  if (!_IO_need_lock (s))
+    {
+      struct Xprintf (buffer_to_file) wrap;
+      Xprintf (buffer_to_file_init) (&wrap, s);
+      Xprintf_buffer (&wrap.base, format, ap, mode_flags);
+      return Xprintf (buffer_to_file_done) (&wrap);
+    }
+
   int done;
 
   /* Lock stream.  */