Re: [PATCH] MIPS: add smp_call_function_single()

[Stephane Eranian <eranian@hpl.hp.com>]

Ralf,

Here is take 2.

[MIPS] add smp_call_function_single (take 2)

signed-off-by: Stephane Eranian <eranian@hpl.hp.com>
signed-off-by: Phil Mucci <mucci@cs.utk.edu>

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index be7362b..d47234c 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -193,6 +193,53 @@ void smp_call_function_interrupt(void)
 	}
 }
 
+int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int retry,
+			     int wait)
+{
+	struct call_data_struct data;
+	int me = smp_processor_id();
+
+	/*
+	 * Can die spectacularly if this CPU isn't yet marked online
+	 */
+	BUG_ON(!cpu_online(me));
+	if (cpu == me) {
+		WARN_ON(1);
+		return -EBUSY;
+	}
+
+	/* Can deadlock when called with interrupts disabled */
+	WARN_ON(irqs_disabled());
+
+	data.func = func;
+	data.info = info;
+	atomic_set(&data.started, 0);
+	data.wait = wait;
+	if (wait)
+		atomic_set(&data.finished, 0);
+
+	spin_lock(&smp_call_lock);
+	call_data = &data;
+	mb();
+
+	/* Send a message to the other CPU */
+	core_send_ipi(cpu, SMP_CALL_FUNCTION);
+
+	/* Wait for response */
+	/* FIXME: lock-up detection, backtrace on lock-up */
+	while (atomic_read(&data.started) != 1)
+		barrier();
+
+	if (wait)
+		while (atomic_read(&data.finished) != 1)
+			barrier();
+	call_data = NULL;
+	spin_unlock(&smp_call_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(smp_call_function_single);
+
 static void stop_this_cpu(void *dummy)
 {
 	/*
-
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