Commit 7e49827c authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

proc: get_nr_threads() doesn't need ->siglock any longer 



Now that task->signal can't go away get_nr_threads() doesn't need
->siglock to read signal->count.

Also, make it inline, move into sched.h, and convert 2 other proc users of
signal->count to use this (now trivial) helper.

Henceforth get_nr_threads() is the only valid user of signal->count, we
are ready to turn it into "int nr_threads" or, perhaps, kill it.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6e1be45a

fs/proc/array.c

+2 −2
Original line number Diff line number Diff line
@@ -267,7 +267,7 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p) 
		shpending = p->signal->shared_pending.signal;

		blocked = p->blocked;

		collect_sigign_sigcatch(p, &ignored, &caught);

		num_threads = atomic_read(&p->signal->count);

		num_threads = get_nr_threads(p);

		rcu_read_lock();  /* FIXME: is this correct? */

		qsize = atomic_read(&__task_cred(p)->user->sigpending);

		rcu_read_unlock();
@@ -410,7 +410,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 
			tty_nr = new_encode_dev(tty_devnum(sig->tty));

		}



		num_threads = atomic_read(&sig->count);

		num_threads = get_nr_threads(task);

		collect_sigign_sigcatch(task, &sigign, &sigcatch);



		cmin_flt = sig->cmin_flt;

fs/proc/base.c

+0 −12
Original line number Diff line number Diff line
@@ -166,18 +166,6 @@ static int get_fs_path(struct task_struct *task, struct path *path, bool root) 
	return result;

}



static int get_nr_threads(struct task_struct *tsk)

{

	unsigned long flags;

	int count = 0;



	if (lock_task_sighand(tsk, &flags)) {

		count = atomic_read(&tsk->signal->count);

		unlock_task_sighand(tsk, &flags);

	}

	return count;

}



static int proc_cwd_link(struct inode *inode, struct path *path)

{

	struct task_struct *task = get_proc_task(inode);

include/linux/sched.h

+5 −0
Original line number Diff line number Diff line
@@ -2147,6 +2147,11 @@ extern bool current_is_single_threaded(void); 
#define while_each_thread(g, t) \

	while ((t = next_thread(t)) != g)



static inline int get_nr_threads(struct task_struct *tsk)

{

	return atomic_read(&tsk->signal->count);

}



/* de_thread depends on thread_group_leader not being a pid based check */

#define thread_group_leader(p)	(p == p->group_leader)

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