From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [RESEND][PATCH 1/2] lib/scatterlist: Make ARCH_HAS_SG_CHAIN an actual Kconfig Date: Sat, 22 Mar 2014 22:52:01 +0000 Message-ID: <20140322225201.GN7528@n2100.arm.linux.org.uk> References: <1395512032-20575-1-git-send-email-lauraa@codeaurora.org> <1395512032-20575-2-git-send-email-lauraa@codeaurora.org> <1395523881.2143.58.camel@dabdike.int.hansenpartnership.com> <20140322222306.GM7528@n2100.arm.linux.org.uk> <1395527860.2143.61.camel@dabdike.int.hansenpartnership.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:35479 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750831AbaCVWwX (ORCPT ); Sat, 22 Mar 2014 18:52:23 -0400 Content-Disposition: inline In-Reply-To: <1395527860.2143.61.camel@dabdike.int.hansenpartnership.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Laura Abbott , Fenghua Yu , Tony Luck , Andrew Morton , linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org, Benjamin Herrenschmidt , x86@kernel.org, Heiko Carstens , linux-kernel@vger.kernel.org, linux390@de.ibm.com, sparclinux@vger.kernel.org, Ingo Molnar , Paul Mackerras , "H. Peter Anvin" , Martin Schwidefsky , linux-ia64@vger.kernel.org, Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , linux-arm-kernel@lists.infradead.org On Sat, Mar 22, 2014 at 03:37:40PM -0700, James Bottomley wrote: > On Sat, 2014-03-22 at 22:23 +0000, Russell King - ARM Linux wrote: > > On Sat, Mar 22, 2014 at 02:31:21PM -0700, James Bottomley wrote: > > > Perhaps now might be the time to ask which are the remaining > > > architectures that cannot do SG chaining and then we can fix them and > > > pull the whole thing out. > > > > Not quite. You're making the assumption that we can be sure that all > > the scatterlist users on an architecture have been converted - that's > > simply not true on ARM. > > No I'm not, I said "now might be the time to ask which are the remaining > architectures that cannot do SG chaining" And I'm disagreeing with that statement which implies that it's something that is an architecture wide property for any particular architecture. Right now in mainline, if ARM has IOMMU support enabled, then SG_CHAIN support will also be enabled. I've a patch out of tree which I've been using for years which enables SG_CHAIN for a particular SoC (Dove). Otherwise, it doesn't have support for SG_CHAIN. PARISC on the other hand (as you list) has no support to enable SG_CHAIN under any circumstances. Where we're disagreeing is whether this is something that is always-on or always-off for any particular architecture. -- FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly improving, and getting towards what was expected from it.