From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1C22C54E8E for ; Tue, 12 May 2020 02:03:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDCFA2070B for ; Tue, 12 May 2020 02:03:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="m90egbfA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728587AbgELCDZ (ORCPT ); Mon, 11 May 2020 22:03:25 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:12799 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728554AbgELCDW (ORCPT ); Mon, 11 May 2020 22:03:22 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1589249001; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=2g53dCdQCv7gFi9EsXPVGxHD6wMKmmDOZGGpFURnlk4=; b=m90egbfAid6GRbXMhb1MXyIw4eMoCevtLA1i3hgqIwLhqxifWsUI2kHHN+v/dBB6kNMIiMA1 o9uqF2xeJAlLFwl5Tp1IC9eouSQkVA0cm43xTf8Q9Br0OX/x8UUY9UJRC6P8AXVPsH5kbjCO G+cRNLP7KjuPPmw5SAfGPyUZboU= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5eba03e8.7f9bb043f1b8-smtp-out-n01; Tue, 12 May 2020 02:03:20 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 0B039C433F2; Tue, 12 May 2020 02:03:20 +0000 (UTC) Received: from codeaurora.org (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id 501CCC433CB; Tue, 12 May 2020 02:03:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 501CCC433CB Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=hemantk@codeaurora.org From: Hemant Kumar To: manivannan.sadhasivam@linaro.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, jhugo@codeaurora.org, bbhatt@codeaurora.org, Hemant Kumar Subject: [PATCH v1 5/5] bus: mhi: core: Handle write lock properly in mhi_pm_m0_transition Date: Mon, 11 May 2020 19:03:09 -0700 Message-Id: <1589248989-23824-6-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1589248989-23824-1-git-send-email-hemantk@codeaurora.org> References: <1589248989-23824-1-git-send-email-hemantk@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Take write lock only to protect db_mode member of mhi channel. This allows rest of the mhi channels to just take read lock which fine grains the locking. It prevents channel readers to starve if they try to enter critical section after a writer. Signed-off-by: Hemant Kumar --- drivers/bus/mhi/core/pm.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 345f197..de5abb2 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -288,14 +288,18 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl) for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) { struct mhi_ring *tre_ring = &mhi_chan->tre_ring; - write_lock_irq(&mhi_chan->lock); - if (mhi_chan->db_cfg.reset_req) + if (mhi_chan->db_cfg.reset_req) { + write_lock_irq(&mhi_chan->lock); mhi_chan->db_cfg.db_mode = true; + write_unlock_irq(&mhi_chan->lock); + } + + read_lock_irq(&mhi_chan->lock); /* Only ring DB if ring is not empty */ if (tre_ring->base && tre_ring->wp != tre_ring->rp) mhi_ring_chan_db(mhi_cntrl, mhi_chan); - write_unlock_irq(&mhi_chan->lock); + read_unlock_irq(&mhi_chan->lock); } mhi_cntrl->wake_put(mhi_cntrl, false); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project