From: David S. Miller <davem@davemloft.net>
Date: Wed, 18 Aug 2010 05:49:26 +0000 (-0700)
Subject: sparc64: Make rwsems 64-bit.
X-Git-Tag: v2.6.36-rc3~36^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9b3bb86acabe0c05923cea1ed3b0bee9439fef4b;p=pandora-kernel.git

sparc64: Make rwsems 64-bit.

Basically tip-off the powerpc code, use a 64-bit type and atomic64_t
interfaces for the implementation.

This gets us off of the by-hand asm code I wrote, which frankly I
think probably ruins I-cache hit rates.

The idea was the keep the call chains less deep, but anything taking
the rw-semaphores probably is also calling other stuff and therefore
already has allocated a stack-frame.  So no real stack frame savings
ever.

Ben H. has posted patches to make powerpc use 64-bit too and with some
abstractions we can probably use a shared header file somewhere.

With suggestions from Sam Ravnborg.

Signed-off-by: David S. Miller <davem@davemloft.net>
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