From patchwork Tue May 12 02:03:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 11541901 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D50EF14B4 for ; Tue, 12 May 2020 02:03:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBC2120722 for ; Tue, 12 May 2020 02:03:22 +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="nFdsSVXq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728115AbgELCDW (ORCPT ); Mon, 11 May 2020 22:03:22 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:41432 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728073AbgELCDV (ORCPT ); Mon, 11 May 2020 22:03:21 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1589249000; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=2g53dCdQCv7gFi9EsXPVGxHD6wMKmmDOZGGpFURnlk4=; b=nFdsSVXqNJ78YRAk3jdBEqHBEJOFY77HQQ4Ick48bIS0q1TjpKjDaCS7gqxfnENPdVIfXw8/ aEOSjNtsHw7VL6Xe7avCssW9UfgykrOto9etd8Qmd1f2Dbnbn5aYBV539WvLcDOUcODELMIB 0IKvqqnBcG+2676lF3UsGIx6NMk= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== 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) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=2.0 tests=ALL_TRUSTED,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.0 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-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@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 Reviewed-by: Manivannan Sadhasivam --- 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);