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=-15.3 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=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 09796C433C1 for ; Sat, 20 Mar 2021 05:31:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF43361943 for ; Sat, 20 Mar 2021 05:31:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229546AbhCTFaz (ORCPT ); Sat, 20 Mar 2021 01:30:55 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:53757 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229449AbhCTFav (ORCPT ); Sat, 20 Mar 2021 01:30:51 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1616218251; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=tVFo5x+lxEseDgWsohpDyCKYL21MNOsMDKQ0tV9WPrU=; b=szdbahO8c4x9XunvlRJmTz7IaUgNogb5ei+x6DJnE69NZKpOpwO/g2SvFAyKrhg2Cu9Ja4qT Qcs1t+kKn4z57wpNsvu7YUPemD5pKoAB4lwVpoRDEfy0YCAGkQFf8pgHjZvZnCrUspAPP4XP +62xjIzVhC5IyjIXGwnQ8pBS5Bk= X-Mailgun-Sending-Ip: 69.72.43.7 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 smtp-out-n07.prod.us-west-2.postgun.com with SMTP id 6055887ee2200c0a0d48cfd0 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Sat, 20 Mar 2021 05:30:38 GMT Sender: wcheng=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id AE13DC433CA; Sat, 20 Mar 2021 05:30:38 +0000 (UTC) Received: from [10.110.100.126] (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: wcheng) by smtp.codeaurora.org (Postfix) with ESMTPSA id 4156AC433C6; Sat, 20 Mar 2021 05:30:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 4156AC433C6 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=wcheng@codeaurora.org Subject: Re: [PATCH 2/2] usb: dwc3: gadget: Ignore EP queue requests during bus reset To: Thinh Nguyen , "balbi@kernel.org" , "gregkh@linuxfoundation.org" Cc: "linux-kernel@vger.kernel.org" , "linux-usb@vger.kernel.org" References: <1616146285-19149-1-git-send-email-wcheng@codeaurora.org> <1616146285-19149-3-git-send-email-wcheng@codeaurora.org> <1886f649-3da2-de25-405c-69c66876b0fd@codeaurora.org> From: Wesley Cheng Message-ID: Date: Fri, 19 Mar 2021 22:30:36 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thinh, On 3/19/2021 7:01 PM, Thinh Nguyen wrote: > Wesley Cheng wrote: >> >> >> On 3/19/2021 5:40 PM, Thinh Nguyen wrote: >>> Hi, >>> >>> Wesley Cheng wrote: >>>> The current dwc3_gadget_reset_interrupt() will stop any active >>>> transfers, but only addresses blocking of EP queuing for while we are >>>> coming from a disconnected scenario, i.e. after receiving the disconnect >>>> event. If the host decides to issue a bus reset on the device, the >>>> connected parameter will still be set to true, allowing for EP queuing >>>> to continue while we are disabling the functions. To avoid this, set the >>>> connected flag to false until the stop active transfers is complete. >>>> >>>> Signed-off-by: Wesley Cheng >>>> --- >>>> drivers/usb/dwc3/gadget.c | 9 +++++++++ >>>> 1 file changed, 9 insertions(+) >>>> >>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c >>>> index 6e14fdc..d5ed0f69 100644 >>>> --- a/drivers/usb/dwc3/gadget.c >>>> +++ b/drivers/usb/dwc3/gadget.c >>>> @@ -3327,6 +3327,15 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc) >>>> u32 reg; >>>> >>>> /* >>>> + * Ideally, dwc3_reset_gadget() would trigger the function >>>> + * drivers to stop any active transfers through ep disable. >>>> + * However, for functions which defer ep disable, such as mass >>>> + * storage, we will need to rely on the call to stop active >>>> + * transfers here, and avoid allowing of request queuing. >>>> + */ >>>> + dwc->connected = false; >>>> + >>>> + /* >>>> * WORKAROUND: DWC3 revisions <1.88a have an issue which >>>> * would cause a missing Disconnect Event if there's a >>>> * pending Setup Packet in the FIFO. >>>> >>> >>> This doesn't look right. Did you have rebase issue with your local >>> change again? >>> >>> BR, >>> Thinh >>> >> Hi Thinh, >> >> This was rebased on Greg's usb-linus branch, which has commit >> f09ddcfcb8c5 ("usb: dwc3: gadget: Prevent EP queuing while stopping >> transfers") merged. > > Ah I see. > >> >> commit f09ddcfcb8c5 moved the dwc->connected = true to after we have >> finished stop active transfers. However, this change will also ensure >> that the connected flag is set to false to ensure that when we call stop >> active transfers, nothing can prepare TRBs. (previous commit only >> addresses the case where we get the reset interrupt when coming from a >> disconnected state) >> > > That still doesn't address this issue. > > Because: > 1) We're still protected by the spin_lock_irq*(), so this change doesn't > make any difference while handling an event. Thank you for the feedback. So it is true that we lock dwc->lock while handling EP/device events, but what these changes are trying to address is that during dwc3_stop_active_transfers() we will eventually call dwc3_gadget_giveback() to call the complete() functions registered by the function driver. Before we call the complete() callbacks, we unlock dwc->lock, so we are no longer protected, and if there was a pending ep queue from a function driver, that would allow it to acquire the lock and continue preparing the TRBs. > 2) We don't enable the interrupt for END_TRANSFER command completion > when doing dwc3_stop_active_transfers(), the > DWC3_EP_END_TRANSFER_PENDING flag will not be set to prevent preparing > new requests. > Agreed. That is the reason for adding the check to dwc->connected in __dwc3_gadget_ep_queue() if (!dep->endpoint.desc || !dwc->pullups_connected || !dwc->connected) { dev_err(dwc->dev, "%s: can't queue to disabled endpoint\n", dep->name); return -ESHUTDOWN; > We should do dwc->connected = true when we handle connection_done > interrupt instead. The END_TRANSFER command should complete before this. > So how this change will address the issue is: 1. IRQ handler will acquire dwc->lock 2. dwc3_gadget_reset_handler() sets dwc->connected = false 3. Call to dwc3_stop_active_transfers() ---> dwc3_gadget_giveback() releases dwc->lock 4. If there was a pending ep queue (waiting for dwc->lock) it can continue here 5. __dwc3_gadget_ep_queue() exits early due to dwc->connected = false 6. dwc3_gadget_giveback() re-acquires dwc->lock and continues Thanks Wesley Cheng -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project