From nobody Fri Dec 19 20:14:09 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E54213C9B2; Sun, 24 Mar 2024 23:52:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711324379; cv=none; b=jswZEn8cbZ64KhIzPJFvysfUUextnwlfaqth8pCrdQCntDEY9JfDQ2TcDYWv6j0aOd9O81sPtvfplMRz68X3s7aGR2ckJvEJpxcegqYmaOivSbeuePfrPlsvAWOEyzOu8VB/2H9H9cce5iQg3FlWjNaeZAlm/pp1b1SQPnBfa3w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711324379; c=relaxed/simple; bh=NXGz5zQ1cIN41gQxmUZc+/iBhIw/1/8LD1rvp3eyCDw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ghff4G1VxEJvI2dvcZdrzOm0b7kMAYxdEZ7Bc5n2uFQGG4xkx3LdRqQUN1tXFpfq17iXT/ApJfJIXY7TCK9FChSsUAfkViMFFOPPeGKV4FnTktaXb4S4fd679CLdAcNFhbX7Fi8MLDvQF6mKQhTmTaS596yx5QczbJRc43baed4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MJFOu9Nm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MJFOu9Nm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6485C43394; Sun, 24 Mar 2024 23:52:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711324378; bh=NXGz5zQ1cIN41gQxmUZc+/iBhIw/1/8LD1rvp3eyCDw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MJFOu9Nm0ibwdsdirFQ1nIUpVmAl0ixAcNz6gx2HVdAZNAfZliEfihoy4w74rB3c6 UWpjRNAqB3//uYczw3cYeUe2PV2BniTZ4hKJTbr1OJu2HevzIsgcCpwMKg0Akc99PQ ygy+aiP66+lBkN51shnPlsSW1jmhRpiS+N9z4Og0Go5dV3TeF6AHTPXbJxBOnRqvIX gV++jXNf+CSarVp2gZ+93uE8xv3rMLONjDAGa+ptkc4Xz16B6J9ucmaq80mCVvyxWq pKydGmC/VDQcL7z06cKdoVxZk6uicbmizwH+0gUiGybItLNU9Wb+9OP8sboOAz6T1q 7Hn9hCB60fB8w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yewon Choi , Michal Kubiak , Paolo Abeni , Sasha Levin Subject: [PATCH 4.19 144/148] rds: introduce acquire/release ordering in acquire/release_in_xmit() Date: Sun, 24 Mar 2024 19:50:08 -0400 Message-ID: <20240324235012.1356413-145-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324235012.1356413-1-sashal@kernel.org> References: <20240324235012.1356413-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yewon Choi [ Upstream commit 1422f28826d2a0c11e5240b3e951c9e214d8656e ] acquire/release_in_xmit() work as bit lock in rds_send_xmit(), so they are expected to ensure acquire/release memory ordering semantics. However, test_and_set_bit/clear_bit() don't imply such semantics, on top of this, following smp_mb__after_atomic() does not guarantee release ordering (memory barrier actually should be placed before clear_bit()). Instead, we use clear_bit_unlock/test_and_set_bit_lock() here. Fixes: 0f4b1c7e89e6 ("rds: fix rds_send_xmit() serialization") Fixes: 1f9ecd7eacfd ("RDS: Pass rds_conn_path to rds_send_xmit()") Signed-off-by: Yewon Choi Reviewed-by: Michal Kubiak Link: https://lore.kernel.org/r/ZfQUxnNTO9AJmzwc@libra05 Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/rds/send.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/rds/send.c b/net/rds/send.c index c856e6c963af9..dcb338339b717 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -103,13 +103,12 @@ EXPORT_SYMBOL_GPL(rds_send_path_reset); =20 static int acquire_in_xmit(struct rds_conn_path *cp) { - return test_and_set_bit(RDS_IN_XMIT, &cp->cp_flags) =3D=3D 0; + return test_and_set_bit_lock(RDS_IN_XMIT, &cp->cp_flags) =3D=3D 0; } =20 static void release_in_xmit(struct rds_conn_path *cp) { - clear_bit(RDS_IN_XMIT, &cp->cp_flags); - smp_mb__after_atomic(); + clear_bit_unlock(RDS_IN_XMIT, &cp->cp_flags); /* * We don't use wait_on_bit()/wake_up_bit() because our waking is in a * hot path and finding waiters is very rare. We don't want to walk --=20 2.43.0