Thread (85 messages) 85 messages, 12 authors, 2016-01-11

Re: [PATCH v2 17/32] arm: define __smp_xxx

From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2016-01-03 09:12:58
Also in: linux-arch, linux-arm-kernel, linux-s390, linux-sh, linux-um, linuxppc-dev, lkml, sparclinux, virtualization

On Sat, Jan 02, 2016 at 11:24:38AM +0000, Russell King - ARM Linux wrote:
On Thu, Dec 31, 2015 at 09:07:59PM +0200, Michael S. Tsirkin wrote:
quoted
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 <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
In combination with patch 14, this looks like it should result in no
change to the resulting code.

Acked-by: Russell King <redacted>

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?
That'd be tricky to do cleanly since asm-generic depends on
ifndef to add generic variants where needed.

But it would be possible to add a checkpatch test for this.

-- 
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
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