From mboxrd@z Thu Jan 1 00:00:00 1970 From: "tip-bot for Paul E. McKenney" Subject: [tip:core/rcu] drivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering Date: Wed, 3 Jan 2018 08:00:23 -0800 Message-ID: Reply-To: mingo@kernel.org, hpa@zytor.com, Ariel.Elior@cavium.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, tglx@linutronix.de, everest-linux-l2@cavium.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, mingo@kernel.org, Ariel.Elior@cavium.com, hpa@zytor.com, tglx@linutronix.de, everest-linux-l2@cavium.com, paulmck@linux.vnet.ibm.com To: linux-tip-commits@vger.kernel.org Return-path: Received: from terminus.zytor.com ([65.50.211.136]:60477 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185AbeACQBf (ORCPT ); Wed, 3 Jan 2018 11:01:35 -0500 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Commit-ID: cb7e125e03274cffa97d74433c876765efffaf6a Gitweb: https://git.kernel.org/tip/cb7e125e03274cffa97d74433c876765efffaf6a Author: Paul E. McKenney AuthorDate: Mon, 9 Oct 2017 09:26:25 -0700 Committer: Paul E. McKenney CommitDate: Mon, 4 Dec 2017 10:52:52 -0800 drivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering The __qed_spq_block() function expects an smp_read_barrier_depends() to order a prior READ_ONCE() against a later load that does not depend on the prior READ_ONCE(), an expectation that can fail to be met. This commit therefore replaces the READ_ONCE() with smp_load_acquire() and removes the smp_read_barrier_depends(). Signed-off-by: Paul E. McKenney Cc: Ariel Elior Cc: Cc: --- drivers/net/ethernet/qlogic/qed/qed_spq.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qed/qed_spq.c b/drivers/net/ethernet/qlogic/qed/qed_spq.c index be48d9a..c1237ec 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_spq.c +++ b/drivers/net/ethernet/qlogic/qed/qed_spq.c @@ -97,9 +97,7 @@ static int __qed_spq_block(struct qed_hwfn *p_hwfn, while (iter_cnt--) { /* Validate we receive completion update */ - if (READ_ONCE(comp_done->done) == 1) { - /* Read updated FW return value */ - smp_read_barrier_depends(); + if (smp_load_acquire(&comp_done->done) == 1) { /* ^^^ */ if (p_fw_ret) *p_fw_ret = comp_done->fw_return_code; return 0;