Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755289AbbGFUPH (ORCPT ); Mon, 6 Jul 2015 16:15:07 -0400 Received: from mail.codeweavers.com ([216.251.189.131]:49164 "EHLO mail.codeweavers.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751181AbbGFUO4 (ORCPT ); Mon, 6 Jul 2015 16:14:56 -0400 Message-ID: <559AE1BE.5050906@codeweavers.com> Date: Mon, 06 Jul 2015 15:14:54 -0500 From: Jeremy White User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: Oliver Neukum , Krzysztof Opasiak CC: Alan Stern , Hans de Goede , "Daniel P. Berrange" , spice-devel@lists.freedesktop.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [Spice-devel] [RFC PATCH 1/1] Add a usbredir kernel module to remotely connect USB devices over IP. References: <55964CFF.1090803@samsung.com> <1436170821.8225.1.camel@suse.com> In-Reply-To: <1436170821.8225.1.camel@suse.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1208 Lines: 31 On 07/06/2015 03:20 AM, Oliver Neukum wrote: > On Fri, 2015-07-03 at 10:51 +0200, Krzysztof Opasiak wrote: >> Doesn't we have the same problem with functionfs/gadgetfs and >> dummy_hcd? >> Or with fuse? >> >> It's a very generic problem for all "virtualized devices" and it is >> known for quite a long time. This is why many tutorials about swap >> warns >> that swap should be set up only on real block devices which are fully >> served in kernel. > > Indeed. But the point is that it isn't limited to swap. As you as > a page needs to be laundered the problem exists. > Mmapping a file for write (non private) is enough. I'm persuaded to avoid user space in the core design. Anything else fundamental to usbip that should inform the design of a usbredir driver? usbip appears to be based off a 2004 vintage of dummy_hcd. I'll look thoughtfully at the current dummy_hcd; please let me know if there is anything else I should consider. Cheers, Jeremy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/