From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937240AbeE1O73 (ORCPT ); Mon, 28 May 2018 10:59:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:45230 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034079AbeE1KZy (ORCPT ); Mon, 28 May 2018 06:25:54 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dick Kennedy , James Smart , Hannes Reinecke , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 4.4 263/268] scsi: lpfc: Fix frequency of Release WQE CQEs Date: Mon, 28 May 2018 12:03:57 +0200 Message-Id: <20180528100232.712860896@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100202.045206534@linuxfoundation.org> References: <20180528100202.045206534@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Smart [ Upstream commit 04673e38f56b30cd39b1fa0f386137d818b17781 ] The driver controls when the hardware sends completions that communicate consumption of elements from the WQ. This is done by setting a WQEC bit on a WQE. The current driver sets it on every Nth WQE posting. However, the driver isn't clearing the bit if the WQE is reused. Thus, if the queue depth isn't evenly divisible by N, with enough time, it can be set on every element, creating a lot of overhead and risking CQ full conditions. Correct by clearing the bit when not setting it on an Nth element. Signed-off-by: Dick Kennedy Signed-off-by: James Smart Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/lpfc/lpfc_sli.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -115,6 +115,8 @@ lpfc_sli4_wq_put(struct lpfc_queue *q, u /* set consumption flag every once in a while */ if (!((q->host_index + 1) % q->entry_repost)) bf_set(wqe_wqec, &wqe->generic.wqe_com, 1); + else + bf_set(wqe_wqec, &wqe->generic.wqe_com, 0); if (q->phba->sli3_options & LPFC_SLI4_PHWQ_ENABLED) bf_set(wqe_wqid, &wqe->generic.wqe_com, q->queue_id); lpfc_sli_pcimem_bcopy(wqe, temp_wqe, q->entry_size);