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From:   paulmck@kernel.org
To:     rcu@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, mingo@kernel.org,
        jiangshanlai@gmail.com, dipankar@in.ibm.com,
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        "Paul E. McKenney" <paulmck@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
        netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH tip/core/rcu 06/10] bpf/cgroup: Replace rcu_swap_protected() with rcu_replace()
Date:   Tue, 22 Oct 2019 12:12:11 -0700
Message-Id: <20191022191215.25781-6-paulmck@kernel.org>
In-Reply-To: <20191022191136.GA25627@paulmck-ThinkPad-P72>
References: <20191022191136.GA25627@paulmck-ThinkPad-P72>
Sender: linux-kernel-owner@vger.kernel.org
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From: "Paul E. McKenney" <paulmck@kernel.org>

This commit replaces the use of rcu_swap_protected() with the more
intuitively appealing rcu_replace() as a step towards removing
rcu_swap_protected().

Link: https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4gg6Hw@mail.gmail.com/
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
[ paulmck: From rcu_replace() to rcu_replace_pointer() per Ingo Molnar. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: <netdev@vger.kernel.org>
Cc: <bpf@vger.kernel.org>
---
 kernel/bpf/cgroup.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index ddd8add..c684cf4 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -180,8 +180,8 @@ static void activate_effective_progs(struct cgroup *cgrp,
 				     enum bpf_attach_type type,
 				     struct bpf_prog_array *old_array)
 {
-	rcu_swap_protected(cgrp->bpf.effective[type], old_array,
-			   lockdep_is_held(&cgroup_mutex));
+	old_array = rcu_replace_pointer(cgrp->bpf.effective[type], old_array,
+					lockdep_is_held(&cgroup_mutex));
 	/* free prog array after grace period, since __cgroup_bpf_run_*()
 	 * might be still walking the array
 	 */
-- 
2.9.5