A single full sync (mb()) is requrired to order the mmio to the qirr reg
with the set or clear of the message word. However, test_and_clear_bit
has the effect of smp_mb() and we are not doing any other io from here,
so we don't need a mb per bit processed.
Signed-off-by: Milton Miller <[EMAIL PROTECTED]>
Index: next.git/arch/powerpc/platforms/pseries/xics.c
===================================================================
--- next.git.orig/arch/powerpc/platforms/pseries/xics.c 2008-10-04
23:56:15.000000000 -0500
+++ next.git/arch/powerpc/platforms/pseries/xics.c 2008-10-05
00:01:26.000000000 -0500
@@ -498,26 +498,23 @@ static irqreturn_t xics_ipi_dispatch(int
{
WARN_ON(cpu_is_offline(cpu));
+ mb(); /* order mmio clearing qirr */
while (xics_ipi_message[cpu].value) {
if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
&xics_ipi_message[cpu].value)) {
- mb();
smp_message_recv(PPC_MSG_CALL_FUNCTION);
}
if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
&xics_ipi_message[cpu].value)) {
- mb();
smp_message_recv(PPC_MSG_RESCHEDULE);
}
if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE,
&xics_ipi_message[cpu].value)) {
- mb();
smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
}
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
&xics_ipi_message[cpu].value)) {
- mb();
smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
}
#endif
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