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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 783E4C2B9F8 for ; Mon, 24 May 2021 16:22:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 592B161403 for ; Mon, 24 May 2021 16:22:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234136AbhEXQYX (ORCPT ); Mon, 24 May 2021 12:24:23 -0400 Received: from so254-9.mailgun.net ([198.61.254.9]:23839 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233783AbhEXQYP (ORCPT ); Mon, 24 May 2021 12:24:15 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1621873367; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=4vyHAaYb4l1Q6HXO7hiHj8To6HZLipzt3FsV5THr0SE=; b=G03qKONhqfLBJYshaHZIv3zPqByC4HLrYvFFTbYM2sMppyFNwJsMS/J81yhRhXEPUFx/FcUD 2gFg58qEu+BTmGWXnsEIra8NQNIaV/C71zkkOJLdf4IV0rK2udjvTCv8xmwVcc1DGv0BAfr6 CHegSnEkGPOy2ZdP8a75L2iR4xs= X-Mailgun-Sending-Ip: 198.61.254.9 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 smtp-out-n01.prod.us-east-1.postgun.com with SMTP id 60abd2d7b15734c8f92acdce (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 24 May 2021 16:22:47 GMT Sender: khsieh=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 32044C0091D; Mon, 24 May 2021 16:22:46 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: khsieh) by smtp.codeaurora.org (Postfix) with ESMTPSA id E288AC43149; Mon, 24 May 2021 16:22:43 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 24 May 2021 09:22:43 -0700 From: khsieh@codeaurora.org To: Stephen Boyd Cc: Rob Clark , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, Dmitry Baryshkov , Abhinav Kumar , aravindh@codeaurora.org, Sean Paul Subject: Re: [PATCH 2/3] drm/msm/dp: Shrink locking area of dp_aux_transfer() In-Reply-To: <20210507212505.1224111-3-swboyd@chromium.org> References: <20210507212505.1224111-1-swboyd@chromium.org> <20210507212505.1224111-3-swboyd@chromium.org> Message-ID: X-Sender: khsieh@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 2021-05-07 14:25, Stephen Boyd wrote: > We don't need to hold the lock to inspect the message we're going to > transfer, and we don't need to clear the busy flag either. Take the > lock > later and bail out earlier if conditions aren't met. > > Cc: Dmitry Baryshkov > Cc: Abhinav Kumar > Cc: Kuogee Hsieh > Cc: aravindh@codeaurora.org > Cc: Sean Paul > Signed-off-by: Stephen Boyd Reviewed-by: Kuogee Hsieh > --- > drivers/gpu/drm/msm/dp/dp_aux.c | 19 +++++++++---------- > 1 file changed, 9 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c > b/drivers/gpu/drm/msm/dp/dp_aux.c > index 91188466cece..b49810396513 100644 > --- a/drivers/gpu/drm/msm/dp/dp_aux.c > +++ b/drivers/gpu/drm/msm/dp/dp_aux.c > @@ -329,30 +329,29 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux > *dp_aux, > ssize_t ret; > int const aux_cmd_native_max = 16; > int const aux_cmd_i2c_max = 128; > - struct dp_aux_private *aux = container_of(dp_aux, > - struct dp_aux_private, dp_aux); > + struct dp_aux_private *aux; > > - mutex_lock(&aux->mutex); > + aux = container_of(dp_aux, struct dp_aux_private, dp_aux); > > aux->native = msg->request & (DP_AUX_NATIVE_WRITE & > DP_AUX_NATIVE_READ); > > /* Ignore address only message */ > - if ((msg->size == 0) || (msg->buffer == NULL)) { > + if (msg->size == 0 || !msg->buffer) { > msg->reply = aux->native ? > DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK; > - ret = msg->size; > - goto unlock_exit; > + return msg->size; > } > > /* msg sanity check */ > - if ((aux->native && (msg->size > aux_cmd_native_max)) || > - (msg->size > aux_cmd_i2c_max)) { > + if ((aux->native && msg->size > aux_cmd_native_max) || > + msg->size > aux_cmd_i2c_max) { > DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n", > __func__, msg->size, msg->request); > - ret = -EINVAL; > - goto unlock_exit; > + return -EINVAL; > } > > + mutex_lock(&aux->mutex); > + > dp_aux_update_offset_and_segment(aux, msg); > dp_aux_transfer_helper(aux, msg, true);