[PATCH] lib: Use RCU_INIT_POINTER(x, NULL) in idr.c

[PATCH] lib: Use RCU_INIT_POINTER(x, NULL) in idr.c

[Monam Agarwal]

This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)

The rcu_assign_pointer() ensures that the initialization of a structure       
is carried out before storing a pointer to that structure. 
And in the case of the NULL pointer, there is no structure to initialize. 
So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL)

Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
---
 lib/idr.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/idr.c b/lib/idr.c
index bfe4db4..f804fbe 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -548,7 +548,7 @@ static void sub_remove(struct idr *idp, int shift, int id)
 	n = id & IDR_MASK;
 	if (likely(p != NULL && test_bit(n, p->bitmap))) {
 		__clear_bit(n, p->bitmap);
-		rcu_assign_pointer(p->ary[n], NULL);
+		RCU_INIT_POINTER(p->ary[n], NULL);
 		to_free = NULL;
 		while(*paa && ! --((**paa)->count)){
 			if (to_free)
@@ -617,7 +617,7 @@ void __idr_remove_all(struct idr *idp)
 
 	n = idp->layers * IDR_BITS;
 	p = idp->top;
-	rcu_assign_pointer(idp->top, NULL);
+	RCU_INIT_POINTER(idp->top, NULL);
 	max = idr_max(idp->layers);
 
 	id = 0;
-- 
1.7.9.5

Re: [PATCH] lib: Use RCU_INIT_POINTER(x, NULL) in idr.c

[Tejun Heo]

On Mon, Mar 24, 2014 at 12:40:08AM +0530, Monam Agarwal wrote:
> This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)
> 
> The rcu_assign_pointer() ensures that the initialization of a structure       
> is carried out before storing a pointer to that structure. 
> And in the case of the NULL pointer, there is no structure to initialize. 
> So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL)
> 
> Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun