From: Jeremy Kerr <jk@ozlabs.org>
Date: Thu, 16 Oct 2008 00:11:12 +0000 (+1100)
Subject: powerpc/spufs: Don't spu_acquire_saved unnecessarily in regs read
X-Git-Tag: v2.6.28-rc1~58^2~33
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f027faa231f38c02e949352735eac76f29090809;p=pandora-kernel.git

powerpc/spufs: Don't spu_acquire_saved unnecessarily in regs read

With most file readers (eg cat, dd), reading a context's regs file will
result in two reads: the first to read the data, and the second to
return EOF. Because each read performs a spu_acquire_saved, we end up
descheduling and re-scheduling the context twice.

This change does a simple check to see if we'd return EOF before
calling spu_acquire_saved(), saving the extra schedule operation.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---

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