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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 5C742C32750 for ; Tue, 13 Aug 2019 18:35:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34D8920843 for ; Tue, 13 Aug 2019 18:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565721303; bh=tHst/Kq9eYMCjaozC3wCdlJ+OCyQ524uuDHDBVOvfdQ=; h=Subject:To:Cc:References:From:Date:In-Reply-To:List-ID:From; b=IQ8lNyph+pvxGZSFxG+8wqzPxz1J3trfeoCTet49W2DJp/BcdrvyK+tZTHNFKuTCx qUWsFepk0t5fJuwyd/hHxNGURDeaDsrmZIExEj6Ylp6Iukq6xnMe5Elg4ZGUaZV/HH 1rRXAWx8xqqz4eed9hJ1VGQLLX1nA5jHBWg9xTzI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726186AbfHMSe6 (ORCPT ); Tue, 13 Aug 2019 14:34:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:35222 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725923AbfHMSe6 (ORCPT ); Tue, 13 Aug 2019 14:34:58 -0400 Received: from [192.168.1.112] (c-24-9-64-241.hsd1.co.comcast.net [24.9.64.241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8F29120665; Tue, 13 Aug 2019 18:34:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565721297; bh=tHst/Kq9eYMCjaozC3wCdlJ+OCyQ524uuDHDBVOvfdQ=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=dJvR0hQCSDUCA4sNDK3nnDtfPfv7lzgE8feZLkhRWZXXPh2BTAS/F7b9S4eUmKgyC JZ++bCJO2Y6an4J/+O/bFPk7OciaEgwAsbVBP+zeL0n3zGbh4opAnlXofW6YbqgyP4 uWktzSTv/YVEo9RKzbp3pI40e2DOtAR/thntScoU= Subject: Re: [PATCH v5 1/2] usbip: Skip DMA mapping and unmapping for urb at vhci To: Suwan Kim , valentina.manea.m@gmail.com, gregkh@linuxfoundation.org, stern@rowland.harvard.edu Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, shuah References: <20190808155435.10050-1-suwan.kim027@gmail.com> <20190808155435.10050-2-suwan.kim027@gmail.com> From: shuah Message-ID: Date: Tue, 13 Aug 2019 12:34:55 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 8/8/19 10:18 AM, shuah wrote: > On 8/8/19 9:54 AM, Suwan Kim wrote: >> vhci doesn’t do DMA for remote device. Actually, the real DMA >> operation is done by network card driver. vhci just passes virtual >> address of the buffer to the network stack, so vhci doesn’t use and >> need dma address of the buffer of the URB. >> >> But HCD provides DMA mapping and unmapping function by default. >> Moreover, it causes unnecessary DMA mapping and unmapping which >> will be done again at the NIC driver and it wastes CPU cycles. >> So, implement map_urb_for_dma and unmap_urb_for_dma function for >> vhci in order to skip the DMA mapping and unmapping procedure. >> >> When it comes to supporting SG for vhci, it is useful to use native >> SG list (urb->num_sgs) instead of mapped SG list because DMA mapping >> fnuction can adjust the number of SG list (urb->num_mapped_sgs). >> And vhci_map_urb_for_dma() prevents isoc pipe from using SG as >> hcd_map_urb_for_dma() does. >> >> Signed-off-by: Suwan Kim >> --- >> v4 - v5 >> - Replace pr_err() with dev_err() in the error path. >> >> v3 - v4 >> - Replace WARN_ON() with pr_err() in the error path. >> >> v2 - v3 >> - Move setting URB_DMA_MAP_SG flag to the patch 2. >> - Prevent isoc pipe from using SG buffer. >> >> v1 - v2 >> - Add setting URB_DMA_MAP_SG flag in urb->transfer_flags to tell >> stub driver to use SG buffer. >> --- >>   drivers/usb/usbip/vhci_hcd.c | 19 +++++++++++++++++++ >>   1 file changed, 19 insertions(+) >> >> diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c >> index 000ab7225717..ea82b932a2f9 100644 >> --- a/drivers/usb/usbip/vhci_hcd.c >> +++ b/drivers/usb/usbip/vhci_hcd.c >> @@ -1288,6 +1288,22 @@ static int vhci_free_streams(struct usb_hcd >> *hcd, struct usb_device *udev, >>       return 0; >>   } >> +static int vhci_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, >> +                gfp_t mem_flags) >> +{ >> +    if (usb_endpoint_xfer_isoc(&urb->ep->desc) && urb->num_sgs) { >> +        dev_err(&urb->dev->dev, "SG is not supported for isochronous >> transfer\n"); >> +        return -EINVAL; >> +    } >> + >> +    return 0; >> +} >> + >> +static void vhci_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb) >> +{ >> +    dev_dbg(hcd->self.controller, "vhci does not unmap urb for dma\n"); >> +} >> + >>   static const struct hc_driver vhci_hc_driver = { >>       .description    = driver_name, >>       .product_desc    = driver_desc, >> @@ -1304,6 +1320,9 @@ static const struct hc_driver vhci_hc_driver = { >>       .get_frame_number = vhci_get_frame_number, >> +    .map_urb_for_dma = vhci_map_urb_for_dma, >> +    .unmap_urb_for_dma = vhci_unmap_urb_for_dma, >> + >>       .hub_status_data = vhci_hub_status, >>       .hub_control    = vhci_hub_control, >>       .bus_suspend    = vhci_bus_suspend, >> > > Looks good to me. > > Reviewed-by: Shuah Khan > Greg! Please pick this one up. Acked-by: Shuah Khan thanks, -- Shuah