Re: [cpuops cmpxchg double V1 2/4] x86: this_cpu_cmpxchg_double()support

From: Christoph Lameter
Date: Wed Dec 15 2010 - 11:21:05 EST


Better comments:

Subject: Fixup comments for cmpxchg16b_cpuops_emu

Indicate that the sematics are not fullly atomic but just per cpu atomic.

Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>

---
arch/x86/lib/cmpxchg16b_emu.S | 4 ++++
1 file changed, 4 insertions(+)

Index: linux-2.6/arch/x86/lib/cmpxchg16b_emu.S
===================================================================
--- linux-2.6.orig/arch/x86/lib/cmpxchg16b_emu.S 2010-12-15 10:18:18.000000000 -0600
+++ linux-2.6/arch/x86/lib/cmpxchg16b_emu.S 2010-12-15 10:19:11.000000000 -0600
@@ -30,6 +30,10 @@ CFI_STARTPROC
# Emulate 'cmpxchg16b %gs:(%rsi)' except we return the result in
# al not via the ZF. Caller will access al to get result.
#
+# Note that this is only useful for a cpuops operation. Meaning that we
+# do *not* have a fully atomic operation but just an operation that is
+# *atomic* on a single cpu (as provided by the this_cpu_xx class of macros)
+#
cmpxchg16b_cpuops_emu:
pushf
cli

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