From: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Date: Sat, 25 Oct 2008 14:51:19 +0000 (+0100)
Subject: udevd: avoid implicit memset in match_attr()
X-Git-Tag: 174~1377
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=cd94c04c518fffbf7f2c173952d77414a5d6bb6b

udevd: avoid implicit memset in match_attr()

Initializing a char array to "" is equivalent to a memset()
call - which is exactly what it gets compiled to.

Fixing this one callsite reduced memset() _user_ cpu cycles
from 2-4% to 0.05% on the EeePC.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
---

diff --git a/udev/udev-rules.c b/udev/udev-rules.c
index 4df9eb35c..44b26906b 100644
--- a/udev/udev-rules.c
+++ b/udev/udev-rules.c
@@ -1794,10 +1794,11 @@ static int match_attr(struct udev_rules *rules, struct udev_device *dev, struct
 	char attr[UTIL_PATH_SIZE];
 	const char *key_name = &rules->buf[cur->key.attr_off];
 	const char *key_value = &rules->buf[cur->key.value_off];
-	char value[UTIL_NAME_SIZE] = "";
+	char value[UTIL_NAME_SIZE];
 	size_t len;
 
 	util_strlcpy(attr, key_name, sizeof(attr));
+	util_strlcpy(value, "", sizeof(value));
 	util_resolve_subsys_kernel(event->udev, attr, value, sizeof(value), 1);
 	if (value[0] == '\0') {
 		const char *val;