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=-15.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 E8777C433DB for ; Fri, 26 Feb 2021 21:16:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B49964F13 for ; Fri, 26 Feb 2021 21:16:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229571AbhBZVQh (ORCPT ); Fri, 26 Feb 2021 16:16:37 -0500 Received: from z11.mailgun.us ([104.130.96.11]:62700 "EHLO z11.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230018AbhBZVQf (ORCPT ); Fri, 26 Feb 2021 16:16:35 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1614374174; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=i4IYjP9ShPsCXpO54hPGJdefd6O+Ag/UKRehCX9Zvq4=; b=r6HJX67Tjd4QDx2XVnaqNZJEiAnJVCsgdbN2aDloUG/6yiXGRO0yimW0z2LAjZpi0RSO7B+u ug3OpiDjPyzgPH4EdIpFkEHrv+9iR+QbohrZL3Ipm0uamu23+73Ro6LNAgGxUjPNWnH9Y0sA sHUAwUL7Ld21WlAdFHyZ5SiNeC8= X-Mailgun-Sending-Ip: 104.130.96.11 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-n04.prod.us-east-1.postgun.com with SMTP id 603964ffea39d1db6d7ce592 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 26 Feb 2021 21:15:43 GMT Sender: hemantk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 9EEDAC43461; Fri, 26 Feb 2021 21:15:42 +0000 (UTC) Received: from [10.46.162.249] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id 70E90C433C6; Fri, 26 Feb 2021 21:15:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 70E90C433C6 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=fail smtp.mailfrom=hemantk@codeaurora.org Subject: Re: [PATCH v2] mhi: Fix invalid error returning in mhi_queue To: Loic Poulain , manivannan.sadhasivam@linaro.org Cc: jhugo@codeaurora.org, bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org References: <1614336782-5809-1-git-send-email-loic.poulain@linaro.org> From: Hemant Kumar Message-ID: Date: Fri, 26 Feb 2021 13:15:40 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1614336782-5809-1-git-send-email-loic.poulain@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Loic, On 2/26/21 2:53 AM, Loic Poulain wrote: > mhi_queue returns an error when the doorbell is not accessible in > the current state. This can happen when the device is in non M0 > state, like M3, and needs to be waken-up prior ringing the DB. This > case is managed earlier by triggering an asynchronous M3 exit via > controller resume/suspend callbacks, that in turn will cause M0 > transition and DB update. > > So, since it's not an error but just delaying of doorbell update, there > is no reason to return an error. > > This also fixes a use after free error for skb case, indeed a caller > queuing skb will try to free the skb if the queueing fails, but in > that case queueing has been done. > > Fixes: a8f75cb348fd ("mhi: core: Factorize mhi queuing") > Signed-off-by: Loic Poulain > Reviewed-by: Jeffrey Hugo > Reviewed-by: Bhaumik Bhatt > --- > v2: - Fix/reword commit message > - Add Fixes tag > > drivers/bus/mhi/core/main.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c > index 7fc2482..c780234 100644 > --- a/drivers/bus/mhi/core/main.c > +++ b/drivers/bus/mhi/core/main.c > @@ -1031,12 +1031,8 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, > if (mhi_chan->dir == DMA_TO_DEVICE) > atomic_inc(&mhi_cntrl->pending_pkts); > > - if (unlikely(!MHI_DB_ACCESS_VALID(mhi_cntrl))) { > - ret = -EIO; > - goto exit_unlock; > - } > - > - mhi_ring_chan_db(mhi_cntrl, mhi_chan); > + if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl))) > + mhi_ring_chan_db(mhi_cntrl, mhi_chan); Caller of all of the ring db APIs mhi_ring_chan/er/cmd_db are checking this if condition "if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl)))" every where in the code. Does it make sense to move this check inside the APIs itself, as a clean up. > > exit_unlock: > read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags); > Thanks, Hemant -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project