[IA64] Implement smp_call_function_mask for ia64

This interface provides more flexible functionality for smp
infrastructure ... e.g. KVM frequently needs to operate on
a subset of cpus.
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/smp.c

@@ -209,6 +209,19 @@ send_IPI_allbutself (int op)
 	}
 }
 
+/*
+ * Called with preemption disabled.
+ */
+static inline void
+send_IPI_mask(cpumask_t mask, int op)
+{
+	unsigned int cpu;
+
+	for_each_cpu_mask(cpu, mask) {
+			send_IPI_single(cpu, op);
+	}
+}
+
 /*
  * Called with preemption disabled.
  */
@@ -401,6 +414,75 @@ smp_call_function_single (int cpuid, void (*func) (void *info), void *info, int
 }
 EXPORT_SYMBOL(smp_call_function_single);
 
+/**
+ * smp_call_function_mask(): Run a function on a set of other CPUs.
+ * <mask>	The set of cpus to run on.  Must not include the current cpu.
+ * <func> 	The function to run. This must be fast and non-blocking.
+ * <info>	An arbitrary pointer to pass to the function.
+ * <wait>	If true, wait (atomically) until function
+ *		has completed on other CPUs.
+ *
+ * Returns 0 on success, else a negative status code.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+int smp_call_function_mask(cpumask_t mask,
+			   void (*func)(void *), void *info,
+			   int wait)
+{
+	struct call_data_struct data;
+	cpumask_t allbutself;
+	int cpus;
+
+	spin_lock(&call_lock);
+	allbutself = cpu_online_map;
+	cpu_clear(smp_processor_id(), allbutself);
+
+	cpus_and(mask, mask, allbutself);
+	cpus = cpus_weight(mask);
+	if (!cpus) {
+		spin_unlock(&call_lock);
+		return 0;
+	}
+
+	/* 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);
+
+	call_data = &data;
+	mb(); /* ensure store to call_data precedes setting of IPI_CALL_FUNC*/
+
+	/* Send a message to other CPUs */
+	if (cpus_equal(mask, allbutself))
+		send_IPI_allbutself(IPI_CALL_FUNC);
+	else
+		send_IPI_mask(mask, IPI_CALL_FUNC);
+
+	/* Wait for response */
+	while (atomic_read(&data.started) != cpus)
+		cpu_relax();
+
+	if (wait)
+		while (atomic_read(&data.finished) != cpus)
+			cpu_relax();
+	call_data = NULL;
+
+	spin_unlock(&call_lock);
+	return 0;
+
+}
+EXPORT_SYMBOL(smp_call_function_mask);
+
 /*
  * this function sends a 'generic call function' IPI to all other CPUs
  * in the system.

include/asm-ia64/smp.h

@@ -38,6 +38,9 @@ ia64_get_lid (void)
 	return lid.f.id << 8 | lid.f.eid;
 }
 
+extern int smp_call_function_mask(cpumask_t mask, void (*func)(void *),
+				  void *info, int wait);
+
 #define hard_smp_processor_id()		ia64_get_lid()
 
 #ifdef CONFIG_SMP