From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH v2 17/32] arm: define __smp_xxx Date: Sat, 2 Jan 2016 11:24:38 +0000 Message-ID: <20160102112438.GU8644@n2100.arm.linux.org.uk> References: <1451572003-2440-1-git-send-email-mst@redhat.com> <1451572003-2440-18-git-send-email-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from pandora.arm.linux.org.uk ([78.32.30.218]:35664 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750977AbcABLYr (ORCPT ); Sat, 2 Jan 2016 06:24:47 -0500 Content-Disposition: inline In-Reply-To: <1451572003-2440-18-git-send-email-mst@redhat.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Arnd Bergmann , linux-arch@vger.kernel.org, Andrew Cooper , virtualization@lists.linux-foundation.org, Stefano Stabellini , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , David Miller , linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, x86@kernel.org, user-mode-linux-devel@lists.sourceforge.net, adi-buildroot-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, xen-devel@lists.xenproject.org, Ingo Molnar , Tony Lindgren Andre On Thu, Dec 31, 2015 at 09:07:59PM +0200, Michael S. Tsirkin wrote: > This defines __smp_xxx barriers for arm, > for use by virtualization. > > smp_xxx barriers are removed as they are > defined correctly by asm-generic/barriers.h > > This reduces the amount of arch-specific boiler-plate code. > > Signed-off-by: Michael S. Tsirkin > Acked-by: Arnd Bergmann In combination with patch 14, this looks like it should result in no change to the resulting code. Acked-by: Russell King My only concern is that it gives people an additional handle onto a "new" set of barriers - just because they're prefixed with __* unfortunately doesn't stop anyone from using it (been there with other arch stuff before.) I wonder whether we should consider making the smp memory barriers inline functions, so these __smp_xxx() variants can be undef'd afterwards, thereby preventing drivers getting their hands on these new macros? -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pandora.arm.linux.org.uk ([78.32.30.218]:35664 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750977AbcABLYr (ORCPT ); Sat, 2 Jan 2016 06:24:47 -0500 Date: Sat, 2 Jan 2016 11:24:38 +0000 From: Russell King - ARM Linux Subject: Re: [PATCH v2 17/32] arm: define __smp_xxx Message-ID: <20160102112438.GU8644@n2100.arm.linux.org.uk> References: <1451572003-2440-1-git-send-email-mst@redhat.com> <1451572003-2440-18-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1451572003-2440-18-git-send-email-mst@redhat.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Arnd Bergmann , linux-arch@vger.kernel.org, Andrew Cooper , virtualization@lists.linux-foundation.org, Stefano Stabellini , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , David Miller , linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, x86@kernel.org, user-mode-linux-devel@lists.sourceforge.net, adi-buildroot-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, xen-devel@lists.xenproject.org, Ingo Molnar , Tony Lindgren , Andrey Konovalov Message-ID: <20160102112438.SL2GbZPxY2eDBO5yVLhr42JjAfJY0hgJKev0OoNmMQw@z> On Thu, Dec 31, 2015 at 09:07:59PM +0200, Michael S. Tsirkin wrote: > This defines __smp_xxx barriers for arm, > for use by virtualization. > > smp_xxx barriers are removed as they are > defined correctly by asm-generic/barriers.h > > This reduces the amount of arch-specific boiler-plate code. > > Signed-off-by: Michael S. Tsirkin > Acked-by: Arnd Bergmann In combination with patch 14, this looks like it should result in no change to the resulting code. Acked-by: Russell King My only concern is that it gives people an additional handle onto a "new" set of barriers - just because they're prefixed with __* unfortunately doesn't stop anyone from using it (been there with other arch stuff before.) I wonder whether we should consider making the smp memory barriers inline functions, so these __smp_xxx() variants can be undef'd afterwards, thereby preventing drivers getting their hands on these new macros? -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.