From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manish Chopra Subject: [PATCH v3 net-next 7/7] qed: Fix possible race when reading firmware return code. Date: Fri, 14 Oct 2016 05:19:23 -0400 Message-ID: <1476436763-5274-8-git-send-email-manish.chopra@qlogic.com> References: <1476436763-5274-1-git-send-email-manish.chopra@qlogic.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , Manish Chopra To: Return-path: Received: from mx0a-0016ce01.pphosted.com ([67.231.148.157]:37897 "EHLO mx0b-0016ce01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751852AbcJNKEz (ORCPT ); Fri, 14 Oct 2016 06:04:55 -0400 In-Reply-To: <1476436763-5274-1-git-send-email-manish.chopra@qlogic.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Manish Chopra While handling SPQ ramrod completion, there is a possible race where driver might not read updated fw return code based on ramrod completion done. This patch ensures that fw return code is written first and then completion done flag is updated using appropriate memory barriers. Signed-off-by: Manish Chopra Signed-off-by: Yuval Mintz --- drivers/net/ethernet/qlogic/qed/qed_sp.h | 4 ++-- drivers/net/ethernet/qlogic/qed/qed_spq.c | 12 ++++++------ 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qed/qed_sp.h b/drivers/net/ethernet/qlogic/qed/qed_sp.h index 652c908..27c450f 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_sp.h +++ b/drivers/net/ethernet/qlogic/qed/qed_sp.h @@ -111,8 +111,8 @@ union qed_spq_req_comp { }; struct qed_spq_comp_done { - u64 done; - u8 fw_return_code; + unsigned int done; + u8 fw_return_code; }; struct qed_spq_entry { diff --git a/drivers/net/ethernet/qlogic/qed/qed_spq.c b/drivers/net/ethernet/qlogic/qed/qed_spq.c index 259a615..6c05402 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_spq.c +++ b/drivers/net/ethernet/qlogic/qed/qed_spq.c @@ -54,11 +54,10 @@ static void qed_spq_blocking_cb(struct qed_hwfn *p_hwfn, comp_done = (struct qed_spq_comp_done *)cookie; - comp_done->done = 0x1; - comp_done->fw_return_code = fw_return_code; + comp_done->fw_return_code = fw_return_code; - /* make update visible to waiting thread */ - smp_wmb(); + /* Make sure completion done is visible on waiting thread */ + smp_store_release(&comp_done->done, 0x1); } static int __qed_spq_block(struct qed_hwfn *p_hwfn, @@ -74,8 +73,9 @@ static int __qed_spq_block(struct qed_hwfn *p_hwfn, while (iter_cnt--) { /* Validate we receive completion update */ - smp_rmb(); - if (comp_done->done == 1) { + if (READ_ONCE(comp_done->done) == 1) { + /* Read updated FW return value */ + smp_read_barrier_depends(); if (p_fw_ret) *p_fw_ret = comp_done->fw_return_code; return 0; -- 2.7.2