[PATCH] make taskstats sending completely independent of delay accounting on/off status

Complete the separation of delay accounting and taskstats by ignoring the
return value of delay accounting functions that fill in parts of taskstats
before it is sent out (either in response to a command or as part of a task
exit).

Also make delayacct_add_tsk return silently when delay accounting is turned
off rather than treat it as an error.

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/delayacct.h

@@ -80,9 +80,7 @@ static inline void delayacct_blkio_end(void)
 static inline int delayacct_add_tsk(struct taskstats *d,
 					struct task_struct *tsk)
 {
-	if (likely(!delayacct_on))
-		return -EINVAL;
-	if (!tsk->delays)
+	if (likely(!delayacct_on) || !tsk->delays)
 		return 0;
 	return __delayacct_add_tsk(d, tsk);
 }

kernel/taskstats.c

@@ -177,7 +177,7 @@ static int send_cpu_listeners(struct sk_buff *skb, unsigned int cpu)
 static int fill_pid(pid_t pid, struct task_struct *pidtsk,
 		struct taskstats *stats)
 {
-	int rc;
+	int rc = 0;
 	struct task_struct *tsk = pidtsk;
 
 	if (!pidtsk) {
@@ -196,12 +196,10 @@ static int fill_pid(pid_t pid, struct task_struct *pidtsk,
 	 * Each accounting subsystem adds calls to its functions to
 	 * fill in relevant parts of struct taskstsats as follows
 	 *
-	 *	rc = per-task-foo(stats, tsk);
-	 *	if (rc)
-	 *		goto err;
+	 *	per-task-foo(stats, tsk);
 	 */
 
-	rc = delayacct_add_tsk(stats, tsk);
+	delayacct_add_tsk(stats, tsk);
 	stats->version = TASKSTATS_VERSION;
 
 	/* Define err: label here if needed */