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Jan Beulich authored
They had several problems/shortcomings: Only the first memory operand was mentioned in the 2x32bit asm() operands, and 2x64-bit version had a memory clobber. The first allowed the compiler to not recognize the need to re-load the data in case it had it cached in some register, and the second was overly destructive. The memory operand in the 2x32-bit asm() was declared to only be an output. The types of the local copies of the old and new values were incorrect (as in other per-CPU ops, the types of the per-CPU variables accessed should be used here, to make sure the respective types are compatible). The __dummy variable was pointless (and needlessly initialized in the 2x32-bit case), given that local copies of the inputs already exist. The 2x64-bit variant forced the address of the first object into %rsi, even though this is needed only for the call to the emulation function. The real cmpxchg16b can operate on an memory. At once also change the return value type to what it really is - 'bool'. Signed-off-by:
Jan Beulich <jbeulich@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Howells <dhowells@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4EE86D6502000078000679FE@nat28.tlf.novell.comSigned-off-by:
Ingo Molnar <mingo@elte.hu>
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