Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756170AbYGHOpk (ORCPT ); Tue, 8 Jul 2008 10:45:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751588AbYGHOpa (ORCPT ); Tue, 8 Jul 2008 10:45:30 -0400 Received: from moutng.kundenserver.de ([212.227.126.186]:49314 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751460AbYGHOp3 convert rfc822-to-8bit (ORCPT ); Tue, 8 Jul 2008 10:45:29 -0400 From: Arnd Bergmann To: Maxim Shchetynin Subject: Re: AZFS file system proposal Date: Tue, 8 Jul 2008 16:42:18 +0200 User-Agent: KMail/1.9.9 Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Benjamin Herrenschmidt , Paul Mackerras , Segher Boessenkool , Gunnar von Boehn , Mark Nelson References: <20080618160629.6cd749a8@mercedes-benz.boeblingen.de.ibm.com> <200807011659.33413.arnd@arndb.de> <20080707173923.17dc6c05@mercedes-benz.boeblingen.de.ibm.com> In-Reply-To: <20080707173923.17dc6c05@mercedes-benz.boeblingen.de.ibm.com> X-Face: I@=L^?./?$U,EK.)V[4*>`zSqm0>65YtkOe>TFD'!aw?7OVv#~5xd\s,[~w]-J!)|%=]>=?utf-8?q?+=0A=09=7EohchhkRGW=3F=7C6=5FqTmkd=5Ft=3FLZC=23Q-=60=2E=60Y=2Ea=5E?= =?utf-8?q?3zb?=) =?utf-8?q?+U-JVN=5DWT=25cw=23=5BYo0=267C=26bL12wWGlZi=0A=09=7EJ=3B=5Cwg?= =?utf-8?q?=3B3zRnz?=,J"CT_)=\H'1/{?SR7GDu?WIopm.HaBG=QYj"NZD_[zrM\Gip^U MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200807081642.19507.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX18CrVst8tuEwQfUTCSiiFetZVTL2VuvwUpkddm 35Wt5Um6DU7jj6Nok4cdbFWaTWatPh7OGDriD9rIhtcQViuCVw Fspxyhmy0CqEEKYv7SMdw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1177 Lines: 29 On Monday 07 July 2008, Maxim Shchetynin wrote: > > > +           if (copy_to_user(target, (void*) pin, size)) { > > > +                   rc = -EFAULT; > > > +                   goto out; > > > +           } > > > > Question to the powerpc folks: is copy_to_user safe for an __iomem source? > > Should there be two copies (memcpy_fromio and copy_to_user) instead? > > I leave this question open. > Cc:'ing some more people that might have more of a clue on this question. _memcpy_fromio does a "sync" at the start and an "eieio" at the end. IFAICT, neither are needed here because the source is always memory. It also handles unaligned memory accesses, which copy_to_user should also do correctly, so it *looks* like it should work with just a copy_to_user, but it still feels wrong to use an __iomem pointer as the source for a copy_to_user. Any ideas? Arnd <>< -- 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/