From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 989261B3923; Sun, 24 Nov 2024 15:04:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732460672; cv=none; b=Xn8Ua7mYejtnj8fRTKha0XWAt8HOOdWrVS0LKUANei05B1wQwX2dk7DrsjS8dHgD7x/QJlkSxwFkHyXN9hoJBiqcJg7pMHZfcL2otYyIpLC8/k2//plB2+ctoqh553IaJkUB5jORf4nTLxR3VR4fdDT4DVhPs687WceQONNhYNc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732460672; c=relaxed/simple; bh=NzAhNdIviC4mcJCGvuq35Fppehjrbw/+lTWbWZ/mAFQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hp7LtcLjf+xReX5WeC31r11hR+DkRcOR5mw+Uuw88XirkAnO0J8IMmZKTxRZAyF00kdJq8lo+N/lC+bG767WvvJD9X4y1i6mooPwPx9yxzEncUjC8/4LKXxrBqX5sthmn2i9wdjI+IvY5BlG599XsTDDsnJsOxBFiI4FOAiuk5U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20911C4CECC; Sun, 24 Nov 2024 15:04:27 +0000 (UTC) Date: Sun, 24 Nov 2024 20:34:22 +0530 From: Manivannan Sadhasivam To: Chris Lew Cc: Johan Hovold , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Hemant Kumar , Loic Poulain , Maxim Kochetkov , Manivannan Sadhasivam , Bjorn Andersson , linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Bhaumik Bhatt Subject: Re: [PATCH] net: qrtr: mhi: synchronize qrtr and mhi preparation Message-ID: <20241124150422.nt67aonfknfhz3sc@thinkpad> References: <20241104-qrtr_mhi-v1-1-79adf7e3bba5@quicinc.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Nov 21, 2024 at 04:28:41PM -0800, Chris Lew wrote: > > > On 11/8/2024 2:32 AM, Johan Hovold wrote: > > On Mon, Nov 04, 2024 at 05:29:37PM -0800, Chris Lew wrote: > > > From: Bhaumik Bhatt > > > > > > The call to qrtr_endpoint_register() was moved before > > > mhi_prepare_for_transfer_autoqueue() to prevent a case where a dl > > > callback can occur before the qrtr endpoint is registered. > > > > > > Now the reverse can happen where qrtr will try to send a packet > > > before the channels are prepared. Add a wait in the sending path to > > > ensure the channels are prepared before trying to do a ul transfer. > > > > > > Fixes: 68a838b84eff ("net: qrtr: start MHI channel after endpoit creation") > > > Reported-by: Johan Hovold > > > Closes: https://lore.kernel.org/linux-arm-msm/ZyTtVdkCCES0lkl4@hovoldconsulting.com/ > > > Signed-off-by: Bhaumik Bhatt > > > Signed-off-by: Chris Lew > > > > > @@ -53,6 +54,10 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb) > > > if (skb->sk) > > > sock_hold(skb->sk); > > > + rc = wait_for_completion_interruptible(&qdev->prepared); > > > + if (rc) > > > + goto free_skb; > > > + > > > rc = skb_linearize(skb); > > > if (rc) > > > goto free_skb; > > > @@ -85,6 +90,7 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev, > > > qdev->mhi_dev = mhi_dev; > > > qdev->dev = &mhi_dev->dev; > > > qdev->ep.xmit = qcom_mhi_qrtr_send; > > > + init_completion(&qdev->prepared); > > > dev_set_drvdata(&mhi_dev->dev, qdev); > > > rc = qrtr_endpoint_register(&qdev->ep, QRTR_EP_NID_AUTO); > > > @@ -97,6 +103,7 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev, > > > qrtr_endpoint_unregister(&qdev->ep); > > > return rc; > > > } > > > + complete_all(&qdev->prepared); > > > dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n"); > > > > While this probably works, it still looks like a bit of a hack. > > > > Why can't you restructure the code so that the channels are fully > > initialised before you register or enable them instead? > > > > Ok, I think we will have to stop using the autoqueue feature of MHI and > change the flow to be mhi_prepare_for_transfer() --> > qrtr_endpoint_register() --> mhi_queue_buf(DMA_FROM_DEVICE). This would make > it so ul_transfers only happen after mhi_prepare_for_transfer() and > dl_transfers happen after qrtr_endpoint_register(). > > I'll take a stab at implementing this. > Hmm, I thought 'autoqueue' was used for a specific reason. So it is not valid now? - Mani -- மணிவண்ணன் சதாசிவம்