sched: Fix string comparison in /proc/sched_features

Fix incorrect handling of the following case:

 INTERACTIVE
 INTERACTIVE_SOMETHING_ELSE

The comparison only checks up to each element's length.

Changelog since v1:
 - Embellish using some Rostedtisms.
  [ mingo:                 ^^ == smaller and cleaner ]

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tony Lindgren <tony@atomide.com>
LKML-Reference: <20100913214700.GB16118@Krystal>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -721,7 +721,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
 		size_t cnt, loff_t *ppos)
 {
 	char buf[64];
-	char *cmp = buf;
+	char *cmp;
 	int neg = 0;
 	int i;
 
@@ -732,6 +732,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
 		return -EFAULT;
 
 	buf[cnt] = 0;
+	cmp = strstrip(buf);
 
 	if (strncmp(buf, "NO_", 3) == 0) {
 		neg = 1;
@@ -739,9 +740,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
 	}
 
 	for (i = 0; sched_feat_names[i]; i++) {
-		int len = strlen(sched_feat_names[i]);
-
-		if (strncmp(cmp, sched_feat_names[i], len) == 0) {
+		if (strcmp(cmp, sched_feat_names[i]) == 0) {
 			if (neg)
 				sysctl_sched_features &= ~(1UL << i);
 			else