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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 A19CAC433DF for ; Thu, 21 May 2020 17:04:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8097F20829 for ; Thu, 21 May 2020 17:04:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="VU+iXWhu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730275AbgEUREA (ORCPT ); Thu, 21 May 2020 13:04:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729920AbgEUREA (ORCPT ); Thu, 21 May 2020 13:04:00 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 022C3C061A0E for ; Thu, 21 May 2020 10:04:00 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id s69so3375744pjb.4 for ; Thu, 21 May 2020 10:03:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=EeYtHIYOhrBA6OPifmOIKFP4kcfASZVORto+oyQu4tM=; b=VU+iXWhu8jPKHtKUJEIRnGgT/2Hm+/4/RF/Dbewzzcq180H59sc/L9XTpCLu0FkBQv DmGjRsT8C+QYWVHh3f4U6rn2sIqQfTqyxTjXgbe3XiFUXuR1VLUI1QANqf4O52EdVm+z 0e5vNFGhZBuf/DufmJ0c5ax+akqd23Trbvu0I+05FQsmDLwIPD7SJjErm6J3pHmGL35J azIzm4Z8g18AKgvHnkwffDpvQraKMiUo8UJgCx5Hlaq/pd0IdX/NuqbdNhDxRzyADWZ8 iAGRKel6qagYv3mBsnvs9jOrK3XwhMiC7TsM0ap7QvfK3tH7k7xbWs/XFSH/dA0ue/vo pRQg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=EeYtHIYOhrBA6OPifmOIKFP4kcfASZVORto+oyQu4tM=; b=HwxWMuGilwTZTU8Op9lxQBvb0nY4C406522zrSG0WgLi5f7qnVCzRsz24UREq3G7uL bhCrQ8b7nserA4twriyu5XI61bi+sbfR1Mf6wvoWKMvue/SUHRcFUQeWG+zCfZJlQOhM GFsohSmZcJuLB8DERsoiCSazx8CnxDx87T3afZRjyYDwyGfdBHpuB0lfj3YgDQtnaY9I C6G+jCodiPOTBc17GKQALqXQOriky2ynglF40FtSzOFyJF2v5LbnYYkl5QB4s5l56TJK sZ3MCI9vVnkSOw9ZGHT6H9gotv26ztiIq1LZlg6eDEhUn2gwWNn9KixrDhrQThbS4Qbh ZCGA== X-Gm-Message-State: AOAM531SdDnFvraPXX91HUYYW+MuxhoW+Lv2PLMo7N6LFbufmfzblI34 7CXSLj2SekdS06o6KC8OYtZq X-Google-Smtp-Source: ABdhPJytAabPuW4Vy17vaIbjJOJVfAsJ5CMiw1EV2ncVPoTOY6irlTOJUCuJB/k/HAva2kBRRy/coQ== X-Received: by 2002:a17:90a:5288:: with SMTP id w8mr9815699pjh.66.1590080639483; Thu, 21 May 2020 10:03:59 -0700 (PDT) Received: from localhost.localdomain ([2409:4072:69f:45f2:3d8d:3719:f568:7ee9]) by smtp.gmail.com with ESMTPSA id e26sm4874693pff.137.2020.05.21.10.03.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 May 2020 10:03:58 -0700 (PDT) From: Manivannan Sadhasivam To: gregkh@linuxfoundation.org Cc: hemantk@codeaurora.org, jhugo@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Manivannan Sadhasivam Subject: [RESEND PATCH 13/14] bus: mhi: core: Handle write lock properly in mhi_pm_m0_transition Date: Thu, 21 May 2020 22:32:48 +0530 Message-Id: <20200521170249.21795-14-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200521170249.21795-1-manivannan.sadhasivam@linaro.org> References: <20200521170249.21795-1-manivannan.sadhasivam@linaro.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org From: Hemant Kumar 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 Signed-off-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 a5d9973059c8..e6236a3ca39d 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); -- 2.17.1