From mboxrd@z Thu Jan  1 00:00:00 1970
From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Date: Thu, 14 Jan 2016 23:04:18 +0000
Subject: Re: [v3,11/41] mips: reuse asm-generic/barrier.h
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To: paulmck@linux.vnet.ibm.com
Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, Peter Zijlstra <peterz@infradead.org>, Will Deacon <will.deacon@arm.com>, virtualization@lists.linux-foundation.org, "H. Peter Anvin" <hpa@zytor.com>, sparclinux@vger.kernel.org, Ingo Molnar <mingo@kernel.org>, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Russell King - ARM Linux <linux@arm.linux.org.uk>, user-mode-linux-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, Michael Ellerman <mpe@ellerman.id.au>, x86@kernel.org, xen-devel@lists.xenproject.org, Ingo Molnar <mingo@elte.hu>, linux-xtensa@linux-xtensa.org, james.hogan@imgtec.com, Arnd Bergmann <arnd@arndb.de>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, adi-buildroot-devel@lists.sourceforge.net, ddaney.cavm@gmail.com, Thomas Gleixner <tglx@linutronix.de>, linux-metag@vger.kernel.orglinux-a

On 01/14/2016 02:24 PM, Paul E. McKenney wrote:
> Actually, the Linux kernel doesn't have an acquire barrier, just an 
> smp_load_acquire(). Or did someone sneak one in while I wasn't looking?
That was an exactly starting point for this discussion. This patch just 
pulls out from MIPS files smp_load_acquire() and smp_store_release(). 
However, I put into LMO half year ago the patch 
http://patchwork.linux-mips.org/patch/10506/ which replaces a generic 
smp_mb with MIPS specific smp_release/acquire in that functions. This 
patch also fixes use of SYNCs barriers in spin_locks/atomics/bitops for 
Imagination MIPS CPUs too - it is just absent now for any Imagination 
MIPS CPUs!

Michael later pointed me that it can be returned back with his series of 
patches but discussion was already here.

- Leonid.