[PATCH] sched: get rid of p->children use in show_task()

the p->parent PID printout gives us all the information about the
task tree that we need - the eldest_child()/older_sibling()/
younger_sibling() printouts are mostly historic and i do not
remember ever having used those fields. (IMO in fact they confuse
the SysRq-T output.) So remove them.

This code has sentimental value though, those fields and
printouts are one of the oldest ones still surviving from
Linux v0.95's kernel/sched.c:

        if (p->p_ysptr || p->p_osptr)
                printk("   Younger sib=%d, older sib=%d\n\r",
                        p->p_ysptr ? p->p_ysptr->pid : -1,
                        p->p_osptr ? p->p_osptr->pid : -1);
        else
                printk("\n\r");

written 15 years ago, in early 1992.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus 'snif' Torvalds <torvalds@linux-foundation.org>

kernel/sched.c

@@ -4687,27 +4687,6 @@ out_unlock:
 	return retval;
 }
 
-static inline struct task_struct *eldest_child(struct task_struct *p)
-{
-	if (list_empty(&p->children))
-		return NULL;
-	return list_entry(p->children.next,struct task_struct,sibling);
-}
-
-static inline struct task_struct *older_sibling(struct task_struct *p)
-{
-	if (p->sibling.prev==&p->parent->children)
-		return NULL;
-	return list_entry(p->sibling.prev,struct task_struct,sibling);
-}
-
-static inline struct task_struct *younger_sibling(struct task_struct *p)
-{
-	if (p->sibling.next==&p->parent->children)
-		return NULL;
-	return list_entry(p->sibling.next,struct task_struct,sibling);
-}
-
 static const char stat_nam[] = "RSDTtZX";
 
 static void show_task(struct task_struct *p)
@@ -4738,19 +4717,7 @@ static void show_task(struct task_struct *p)
 		free = (unsigned long)n - (unsigned long)end_of_stack(p);
 	}
 #endif
-	printk("%5lu %5d %6d ", free, p->pid, p->parent->pid);
-	if ((relative = eldest_child(p)))
-		printk("%5d ", relative->pid);
-	else
-		printk("      ");
-	if ((relative = younger_sibling(p)))
-		printk("%7d", relative->pid);
-	else
-		printk("       ");
-	if ((relative = older_sibling(p)))
-		printk(" %5d", relative->pid);
-	else
-		printk("      ");
+	printk("%5lu %5d %6d", free, p->pid, p->parent->pid);
 	if (!p->mm)
 		printk(" (L-TLB)\n");
 	else