From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C3E631D61AA; Wed, 30 Apr 2025 05:24:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745990700; cv=none; b=Afd0UfN+RNtK55okg8UjgVbb3wvk0ASdnslD8ZaVTQ5uUBBJxDn7Cy3un5PxNBoMcgVrVY2o3A50ilOEb46kewvB8gpsy672UF5E/66RVtPOca4SrTkFxJOcbtnXLsMPMXuIQ55XFkjyFUenb01B+q2qyeMEJPEYxiPyezoC3Z0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745990700; c=relaxed/simple; bh=oPN9HNb7W+WnV8QqZ69WdQtfENQ8uSEUYUOwpqen8z8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rpogZkvZJRXIrieTIW/rPzzsR/0P/Bc12IMYrwM0OkjZYtRw6bFraBkfSwVPUiEaBtvd9twF/YziHPjbv6QSYMx1fu4L4HpAD6wtQeRqUVkYn+Kbv/urukJ8cLMOr+KWrFbzqfLfymcPj3qQFLYL3ALXmK03/WcRs+Fq4VUm0Ks= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=mgl7xiw3; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="mgl7xiw3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Message-ID:Date:MIME-Version:Subject:From: Content-Type; bh=MVWXoYGa4OsAsg4nc8D9qzEcLgq9gyKCVEtwnH3camo=; b=mgl7xiw3BD4JQ+t5cQFS6f2PNQRy4ucAaDsBHK3E4WqYg+aCGvrH1FyyU0IZ5m ycRbfdoxYzSV1T3uxotcecTXeWDIE1Mil5vKaYkD6730CrV0pAgtK6d9OesylZ+c zT4AkoXyN2c1Cm/ZWotOCtOhBjARuckAfBRRXPrX5b0Uo= Received: from [10.42.12.155] (unknown []) by gzga-smtp-mtada-g0-3 (Coremail) with SMTP id _____wDX01EPtBFodsoXDg--.22173S2; Wed, 30 Apr 2025 13:24:33 +0800 (CST) Message-ID: Date: Wed, 30 Apr 2025 13:24:31 +0800 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] usbip: set the dma mask to 64bit default for vhci-driver To: Shuah Khan , Greg KH Cc: Christoph Hellwig , i@zenithal.me, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, shuah@kernel.org, valentina.manea.m@gmail.com, Zongmin Zhou References: <3e1f8fab-0155-4ff9-800d-5fa9df88c48c@linuxfoundation.org> <20250422063409.607859-1-min_halo@163.com> <4c6660a6-29ce-4b97-b092-8fc15585e52a@163.com> <2025042512-corsage-handpick-bf2a@gregkh> <575ce02c-9128-4098-a852-d9e14f14010e@163.com> <2025042812-sinister-shaping-bded@gregkh> <097ad0fd-db38-4174-8e34-4ceb485e7e23@linuxfoundation.org> Content-Language: en-US From: Zongmin Zhou In-Reply-To: <097ad0fd-db38-4174-8e34-4ceb485e7e23@linuxfoundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wDX01EPtBFodsoXDg--.22173S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxJFWxXry5uw4xJw4kGw45Wrg_yoW5Gw1fpF W3Jay2krs8Kwn2qrnav3W0vF1FyrZ5t34rWrn8Jw18C390qFyavrWDt398CF9Fvr1xK3W2 vrWjgFyakFn8uFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UeKZAUUUUU= X-CM-SenderInfo: pplqsxxdorqiywtou0bp/1tbi7gM-q2gRqVj1hwAAsD On 2025/4/29 07:07, Shuah Khan wrote: > On 4/28/25 04:04, Greg KH wrote: >> A: http://en.wikipedia.org/wiki/Top_post >> Q: Were do I find info about this thing called top-posting? >> A: Because it messes up the order in which people normally read text. >> Q: Why is top-posting such a bad thing? >> A: Top-posting. >> Q: What is the most annoying thing in e-mail? >> >> A: No. >> Q: Should I include quotations after my reply? >> >> http://daringfireball.net/2007/07/on_top >> Sorry for that,and thank you for the comment!I've learned it. >> On Mon, Apr 28, 2025 at 05:51:08PM +0800, Zongmin Zhou wrote: >>> Dear Greg and Shuah, >>> >>> I found out that the vhci-hcd driver added this virtual device >>> as a platform device from the very beginning since 2014. >> >> Ah, I should have caught it back then, but at the time there really >> wasn't another option. >> > >>> I'm just getting in touch with this module and >>> don't have a deep understanding of it，shuah should be clearer. > > faux_device should work fine for this. We do have to test of course. > > There are several examples of converting  platform device to faux device. > > 72239a78f9f5b9f05ea4bb7a15b92807906dab71 > dcd2a9a5550ef556c8fc11601a0f729fb71ead5d > Ok,I will learn to do it. Thank you for your guidance. >> >> See the recent patches I did converting drivers to use the faux bus >> code, it should be pretty simple to do. >> >>> I don't know if using the faux bus to replace the platform bus can >>> solve the >>> problem that the error limitation on max_hw_sectors for usbip device >>> since commit d74ffae8b8dd applied. >> >> That is for the storage driver, not usbip.  As the faux bus does not >> have any real dma operations, this should cause it to work properly >> given the default values involed, but that's up to you to test to verify >> it does just that.  Try it and see! >> >>> But this change will request user to update kernel version to >>> support faux >>> bus. >> >> That's just a normal kernel update to a newer version, what is wrong >> with that? > > With one difference that the fix depends on faux_device feature - hence > we can't apply it to stables. I do think it is the right direction to > go to faux_device. > I just encountered similar users who were using a lower version of the kernel and were unwilling to upgrade. But if reach a consensus to  go to faux_device, I will try to make the change(converting platform device to faux device for vhci-hcd). >> >>> This will also be an expensive change to fix the problem? >> >> Fixing things properly is the correct thing to do in all cases. >> > > Zongmin, do let me know if you are unable to make the change. > > thanks, > -- Shuah