signals: kill the awful task_rq_unlock_wait() hack

oleg-nesterov · torvalds · commit b7b8ff6373d4 · 2010-05-27T09:12:46.000-07:00
Now that task->signal can't go away we can revert the horrible hack added by ad474ca ("fix for account_group_exec_runtime(), make sure ->signal can't be freed under rq->lock"). And we can do more cleanups sched_stats.h/posix-cpu-timers.c later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
@@ -268,7 +268,6 @@ extern void init_idle(struct task_struct *idle, int cpu);
 extern void init_idle_bootup_task(struct task_struct *idle);
 
 extern int runqueue_is_locked(int cpu);
-extern void task_rq_unlock_wait(struct task_struct *p);
 
 extern cpumask_var_t nohz_cpu_mask;
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
diff --git a/kernel/exit.c b/kernel/exit.c
@@ -145,11 +145,6 @@ static void __exit_signal(struct task_struct *tsk)
 	if (sig) {
 		flush_sigqueue(&sig->shared_pending);
 		taskstats_tgid_free(sig);
-		/*
-		 * Make sure ->signal can't go away under rq->lock,
-		 * see account_group_exec_runtime().
-		 */
-		task_rq_unlock_wait(tsk);
 		tty_kref_put(tty);
 	}
 }
diff --git a/kernel/sched.c b/kernel/sched.c
@@ -969,14 +969,6 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
 	}
 }
 
-void task_rq_unlock_wait(struct task_struct *p)
-{
-	struct rq *rq = task_rq(p);
-
-	smp_mb(); /* spin-unlock-wait is not a full memory barrier */
-	raw_spin_unlock_wait(&rq->lock);
-}
-
 static void __task_rq_unlock(struct rq *rq)
 	__releases(rq->lock)
 {

Original file line number	Diff line number	Diff line change
`@@ -145,11 +145,6 @@ static void __exit_signal(struct task_struct *tsk)`
`145`	`145`	`if (sig) {`
`146`	`146`	`flush_sigqueue(&sig->shared_pending);`
`147`	`147`	`taskstats_tgid_free(sig);`
`148`		`- /*`
`149`		`- * Make sure ->signal can't go away under rq->lock,`
`150`		`- * see account_group_exec_runtime().`
`151`		`- */`
`152`		`- task_rq_unlock_wait(tsk);`
`153`	`148`	`tty_kref_put(tty);`
`154`	`149`	`}`
`155`	`150`	`}`
Original file line number	Diff line number	Diff line change
`@@ -969,14 +969,6 @@ static struct rq task_rq_lock(struct task_struct p, unsigned long *flags)`
`969`	`969`	`}`
`970`	`970`	`}`
`971`	`971`
`972`		`-void task_rq_unlock_wait(struct task_struct *p)`
`973`		`-{`
`974`		`- struct rq *rq = task_rq(p);`
`975`		`-`
`976`		`- smp_mb(); /* spin-unlock-wait is not a full memory barrier */`
`977`		`- raw_spin_unlock_wait(&rq->lock);`
`978`		`-}`
`979`		`-`
`980`	`972`	`static void __task_rq_unlock(struct rq *rq)`
`981`	`973`	`__releases(rq->lock)`
`982`	`974`	`{`