Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753787AbbDGT7h (ORCPT ); Tue, 7 Apr 2015 15:59:37 -0400 Received: from mail-lb0-f182.google.com ([209.85.217.182]:36296 "EHLO mail-lb0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751162AbbDGT7e (ORCPT ); Tue, 7 Apr 2015 15:59:34 -0400 Date: Tue, 7 Apr 2015 21:59:32 +0200 From: Johan Hovold To: Alan Stern Cc: Johan Hovold , Greg Kroah-Hartman , Felipe Balbi , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Stephen Warren , Thierry Reding , Alexandre Courbot , linux-tegra@vger.kernel.org, stable Subject: Re: [PATCH 2/2] USB: ehci-tegra: fix inefficient copy of unaligned buffers Message-ID: <20150407195932.GB12027@localhost> References: <1428400012-7563-3-git-send-email-johan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1105 Lines: 25 On Tue, Apr 07, 2015 at 11:30:15AM -0400, Alan Stern wrote: > On Tue, 7 Apr 2015, Johan Hovold wrote: > > > Make sure only to copy any actual data rather than the whole buffer, > > when releasing the temporary buffer used for unaligned transfer buffers. > > > > Note that the corresponding fix of musb also fixes a lockup on > > disconnect, where repeated failed transfers would starve the hub > > workqueue from processing the disconnect, which would have prevented the > > urbs from being resubmitted. In this case there is no data to forward, > > but the full buffer length was being copied nonetheless. > > This is wrong for isochronous transfers, because the transfer data > generally isn't contiguous in memory. > > It would be okay to do this for other transfer types, though. Thanks for pointing that out. I'll re-spin the series tomorrow. Johan -- 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/