From mboxrd@z Thu Jan 1 00:00:00 1970 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 BA01F15689D; Sun, 24 Mar 2024 23:11:22 +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=1711321883; cv=none; b=Mdc5oXT9Tp7Jg5XBXBBBJw8/kkoIT2cTIPEXYc5+PD63KMhIzsmjcgzZB10v/Nz4lZQau975xeBWEcanuXBFahaihBnHxTdeQXeJ6cXyGyNkc6A9h1aZg6FsRoVdQbLm+rhNMGJDKo9d5slCNS8jmrbk9hXbwI2OZohVn4EHSUc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321883; c=relaxed/simple; bh=BjRnn2uAci+SuwZsSH8Z6eRxLJRWal9cId1CxlbJEoA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bvLplZYjdqaKEM4tvljsuewjvP5N/PSehCq1BYHxC8H/08PgZqpMJp/arQu3dDpxxa/zXPcAu2Gs8K9YQuhMimqJ8f5mILxoUB10b7PLFOXJXrXDedMN567ZiLPer3tpdIx62TF+7P86/pM+QTiHU7iK4czb5HVFkDQgDohHUH0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EH/Djeog; 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="EH/Djeog" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 891C1C433C7; Sun, 24 Mar 2024 23:11:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321882; bh=BjRnn2uAci+SuwZsSH8Z6eRxLJRWal9cId1CxlbJEoA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EH/DjeogaL+clwxtIrK0xZTDiCCnrGZ9TH1nAIR4AElCIXhxWvcJODuimNUzrDkVy TY+SA3ceI0e4Dr2tE7h9Y+n0XEbFN5MouGVbrZjJb2pQOSQwoP3YTKM6Soe/CUvJwi cG1gfmDZFtVCIqwhXKqySe/GTo1EDYNwpNKiKztw7//4SJ2xoMlmk3FIVaXMes0aCP OyJUhFqapaEh1Qxt9S3aa6tyzphGjGU6rXW2Ge9NPLhNJfSM9cR2PI63xEhYLggELn Mx/mX81kTJm71oVJoLJCTvwIKiu4URb39u0HOZ4GF0NiHf6Lyla+MOdSoeJJ+AGcCS IxtqY8g0V/TRw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yewon Choi , Michal Kubiak , Paolo Abeni , Sasha Levin Subject: [PATCH 6.6 610/638] rds: introduce acquire/release ordering in acquire/release_in_xmit() Date: Sun, 24 Mar 2024 19:00:47 -0400 Message-ID: <20240324230116.1348576-611-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324230116.1348576-1-sashal@kernel.org> References: <20240324230116.1348576-1-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: 8bit 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 2899def23865f..09a2801106549 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -103,13 +103,12 @@ EXPORT_SYMBOL_GPL(rds_send_path_reset); static int acquire_in_xmit(struct rds_conn_path *cp) { - return test_and_set_bit(RDS_IN_XMIT, &cp->cp_flags) == 0; + return test_and_set_bit_lock(RDS_IN_XMIT, &cp->cp_flags) == 0; } 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 -- 2.43.0