From: Benjamin LaHaise <bcrl@kvack.org>
Date: Fri, 30 Aug 2013 15:12:50 +0000 (-0400)
Subject: aio: fix rcu sparse warnings introduced by ioctx table lookup patch
X-Git-Tag: upstream/snapshot3+hdmi~4306^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=77d30b14d24e557f89c41980011d72428514d729;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

aio: fix rcu sparse warnings introduced by ioctx table lookup patch

Sseveral sparse warnings were caused by missing rcu_dereference() annotations
for dereferencing mm->ioctx_table.  Thankfully, none of those were actual bugs
as the deref was protected by a spin lock in all instances.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
---

diff --git a/fs/aio.c b/fs/aio.c
index d0defcb..6e26755 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -470,7 +470,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
 	struct aio_ring *ring;
 
 	spin_lock(&mm->ioctx_lock);
-	table = mm->ioctx_table;
+	table = rcu_dereference(mm->ioctx_table);
 
 	while (1) {
 		if (table)
@@ -498,7 +498,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
 		table->nr = new_nr;
 
 		spin_lock(&mm->ioctx_lock);
-		old = mm->ioctx_table;
+		old = rcu_dereference(mm->ioctx_table);
 
 		if (!old) {
 			rcu_assign_pointer(mm->ioctx_table, table);
@@ -622,7 +622,7 @@ static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx)
 		struct kioctx_table *table;
 
 		spin_lock(&mm->ioctx_lock);
-		table = mm->ioctx_table;
+		table = rcu_dereference(mm->ioctx_table);
 
 		WARN_ON(ctx != table->table[ctx->id]);
 		table->table[ctx->id] = NULL;