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: Oleg 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: 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/fs/proc/array.c b/fs/proc/array.c
index 885ab55..9b58d38 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -267,7 +267,7 @@
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 @@
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;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c7f9f23..c384e8b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -166,18 +166,6 @@
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);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index dd597d8..ccd2d15 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2147,6 +2147,11 @@
#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)
