From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758605Ab0DHLHv (ORCPT ); Thu, 8 Apr 2010 07:07:51 -0400 Received: from buzzloop.caiaq.de ([212.112.241.133]:32784 "EHLO buzzloop.caiaq.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758571Ab0DHLHs (ORCPT ); Thu, 8 Apr 2010 07:07:48 -0400 Date: Thu, 8 Apr 2010 13:07:43 +0200 From: Daniel Mack To: Oliver Neukum Cc: Greg KH , Alan Stern , linux-kernel@vger.kernel.org, Pedro Ribeiro , akpm@linux-foundation.org, Greg KH , alsa-devel@alsa-project.org, linux-usb@vger.kernel.org Subject: Re: USB transfer_buffer allocations on 64bit systems Message-ID: <20100408110743.GP30807@buzzloop.caiaq.de> References: <20100407090623.GN30807@buzzloop.caiaq.de> <20100407153154.GC13425@kroah.com> <20100407153551.GK30801@buzzloop.caiaq.de> <201004080809.11756.oliver@neukum.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201004080809.11756.oliver@neukum.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 08, 2010 at 08:09:11AM +0200, Oliver Neukum wrote: > Am Mittwoch, 7. April 2010 17:35:51 schrieb Daniel Mack: > > > Alan, any objection to just using usb_buffer_alloc() for every driver? > > > Or is that too much overhead? > > > > FWIW, most drivers I've seen in the past hours use a wild mix of > > kmalloc(), kzalloc(), kcalloc() and usb_buffer_alloc(). That should > > really be unified. > > kmalloc() & friends != usb_buffer_alloc(). They do different things. I know. I just believe that many developers used usb_buffer_alloc() even though they don't really need coherent DMA memory. The function's name is misleading, and copy'n paste does the rest. > It makes no sense to unify them. If you really need an ordinary > buffer DMA will surely work on, this needs a third primitive. I think it will help a lot to rename usb_buffer_alloc() in the first place and then reconsider where coherent memory is really needed. Daniel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Mack Subject: Re: USB transfer_buffer allocations on 64bit systems Date: Thu, 8 Apr 2010 13:07:43 +0200 Message-ID: <20100408110743.GP30807@buzzloop.caiaq.de> References: <20100407090623.GN30807@buzzloop.caiaq.de> <20100407153154.GC13425@kroah.com> <20100407153551.GK30801@buzzloop.caiaq.de> <201004080809.11756.oliver@neukum.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <201004080809.11756.oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Oliver Neukum Cc: Greg KH , Alan Stern , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Pedro Ribeiro , akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, Greg KH , alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: alsa-devel@alsa-project.org On Thu, Apr 08, 2010 at 08:09:11AM +0200, Oliver Neukum wrote: > Am Mittwoch, 7. April 2010 17:35:51 schrieb Daniel Mack: > > > Alan, any objection to just using usb_buffer_alloc() for every driver? > > > Or is that too much overhead? > > > > FWIW, most drivers I've seen in the past hours use a wild mix of > > kmalloc(), kzalloc(), kcalloc() and usb_buffer_alloc(). That should > > really be unified. > > kmalloc() & friends != usb_buffer_alloc(). They do different things. I know. I just believe that many developers used usb_buffer_alloc() even though they don't really need coherent DMA memory. The function's name is misleading, and copy'n paste does the rest. > It makes no sense to unify them. If you really need an ordinary > buffer DMA will surely work on, this needs a third primitive. I think it will help a lot to rename usb_buffer_alloc() in the first place and then reconsider where coherent memory is really needed. Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html