libbb/copyfd.c: don't mmap a largish buffer if we only want to copy a few kb
function old new delta
bb_full_fd_action 283 295 +12
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index c5f8b5b..f42eb76 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -22,6 +22,8 @@
char *buffer;
int buffer_size;
+ if (size > 0 && size <= 4 * 1024)
+ goto use_small_buf;
/* We want page-aligned buffer, just in case kernel is clever
* and can do page-aligned io more efficiently */
buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
@@ -30,6 +32,7 @@
/* ignored: */ -1, 0);
buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
if (buffer == MAP_FAILED) {
+ use_small_buf:
buffer = alloca(4 * 1024);
buffer_size = 4 * 1024;
}