From 777bbe18f49af2754020411a478cbf3389fb29f2 Mon Sep 17 00:00:00 2001
From: Octavian Purdila <tavi@cs.pub.ro>
Date: Thu, 26 Jan 2017 17:28:12 +0200
Subject: [PATCH] lkl: remove threads counter

Now that we have synchronous thread termination due to thread_join
ops, we don't need the threads_counter anymore.

Signed-off-by: Octavian Purdila <tavi@cs.pub.ro>
---
 arch/lkl/include/asm/thread_info.h |  1 -
 arch/lkl/kernel/setup.c            |  1 -
 arch/lkl/kernel/threads.c          | 16 +---------------
 3 files changed, 1 insertion(+), 17 deletions(-)

diff --git a/arch/lkl/include/asm/thread_info.h b/arch/lkl/include/asm/thread_info.h
index 408f4a7ca39106..de00569f158e4c 100644
--- a/arch/lkl/include/asm/thread_info.h
+++ b/arch/lkl/include/asm/thread_info.h
@@ -49,7 +49,6 @@ void free_thread_stack(struct task_struct *tsk);
 
 void threads_init(void);
 void threads_cleanup(void);
-void threads_cnt_dec(void);
 
 #define TIF_SYSCALL_TRACE		0
 #define TIF_NOTIFY_RESUME		1
diff --git a/arch/lkl/kernel/setup.c b/arch/lkl/kernel/setup.c
index 501d32175dc426..d6da246d3a6b28 100644
--- a/arch/lkl/kernel/setup.c
+++ b/arch/lkl/kernel/setup.c
@@ -160,7 +160,6 @@ static int lkl_run_init(struct linux_binprm *bprm)
 	init_pid_ns.child_reaper = 0;
 
 	syscalls_init();
-	threads_cnt_dec();
 
 	lkl_ops->sem_up(init_sem);
 	lkl_ops->thread_exit();
diff --git a/arch/lkl/kernel/threads.c b/arch/lkl/kernel/threads.c
index 3518d804b9c131..caede2f80f2d64 100644
--- a/arch/lkl/kernel/threads.c
+++ b/arch/lkl/kernel/threads.c
@@ -5,8 +5,6 @@
 #include <asm/cpu.h>
 #include <asm/sched.h>
 
-static volatile int threads_counter;
-
 static int init_ti(struct thread_info *ti)
 {
 	ti->sched_sem = lkl_ops->sem_alloc(0);
@@ -122,10 +120,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
 		lkl_ops->sem_down(_prev->sched_sem);
 	}
 
-	if (_prev->dead) {
-		__sync_fetch_and_sub(&threads_counter, 1);
+	if (_prev->dead)
 		lkl_ops->thread_exit();
-	}
 
 	return abs_prev;
 }
@@ -193,8 +189,6 @@ int copy_thread(unsigned long clone_flags, unsigned long esp,
 		return -ENOMEM;
 	}
 
-	__sync_fetch_and_add(&threads_counter, 1);
-
 	return 0;
 }
 
@@ -218,11 +212,6 @@ void threads_init(void)
 	ti->tid = lkl_ops->thread_self();
 }
 
-void threads_cnt_dec(void)
-{
-	__sync_fetch_and_sub(&threads_counter, 1);
-}
-
 void threads_cleanup(void)
 {
 	struct task_struct *p, *t;
@@ -239,8 +228,5 @@ void threads_cleanup(void)
 		kill_thread(ti);
 	}
 
-	while (threads_counter)
-		;
-
 	lkl_ops->sem_free(init_thread_union.thread_info.sched_sem);
 }