Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures

From: Paul Mackerras
Date: Fri Aug 17 2007 - 01:10:36 EST


Herbert Xu writes:

> Can you find an actual atomic_read code snippet there that is
> broken without the volatile modifier?

There are some in arch-specific code, for example line 1073 of
arch/mips/kernel/smtc.c. On mips, cpu_relax() is just barrier(), so
the empty loop body is ok provided that atomic_read actually does the
load each time around the loop.

Paul.
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