[PATCH v2] fork: Fix some -Wmissing-prototypes warnings

[Yi Wang]

We get a warning when building kernel with W=1:
kernel/fork.c:167:13: warning: no previous prototype for âarch_release_thread_stackâ [-Wmissing-prototypes]
kernel/fork.c:779:13: warning: no previous prototype for âfork_initâ [-Wmissing-prototypes]

Add the missing declaration in head file to fix this.

Also, remove arch_release_thread_stack() completely because no
arch seems to implement it since bb9d81264 (arch: remove tile port).

Signed-off-by: Yi Wang <wang.yi59@xxxxxxxxxx>
---
v2: remove arch_release_thread_stack(). Thanks to Rasmus.
---
 include/linux/sched/task.h | 2 ++
 init/main.c                | 1 -
 kernel/fork.c              | 5 -----
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 108ede9..44c6f15 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -39,6 +39,8 @@
 
 extern void proc_caches_init(void);
 
+extern void fork_init(void);
+
 extern void release_task(struct task_struct * p);
 
 #ifdef CONFIG_HAVE_COPY_THREAD_TLS
diff --git a/init/main.c b/init/main.c
index ee14710..8feda42 100644
--- a/init/main.c
+++ b/init/main.c
@@ -105,7 +105,6 @@
 static int kernel_init(void *);
 
 extern void init_IRQ(void);
-extern void fork_init(void);
 extern void radix_tree_init(void);
 
 /*
diff --git a/kernel/fork.c b/kernel/fork.c
index 07cddff..c6d02be 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -164,10 +164,6 @@ static inline void free_task_struct(struct task_struct *tsk)
 }
 #endif
 
-void __weak arch_release_thread_stack(unsigned long *stack)
-{
-}
-
 #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
 
 /*
@@ -417,7 +413,6 @@ static void release_task_stack(struct task_struct *tsk)
 		return;  /* Better to leak the stack than to free prematurely */
 
 	account_kernel_stack(tsk, -1);
-	arch_release_thread_stack(tsk->stack);
 	free_thread_stack(tsk);
 	tsk->stack = NULL;
 #ifdef CONFIG_VMAP_STACK
-- 
1.8.3.1