genirq/timings: Encapsulate storing function

For the next patches providing the selftest, it is required to insert
interval values directly in the buffer in order to check the correctness of
the code. Encapsulate the code doing that in a always inline function in
order to reuse it in the test code.

No functional changes.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20190527205521.12091-6-daniel.lezcano@linaro.org

kernel/irq/timings.c

@@ -430,11 +430,43 @@ static u64 __irq_timings_next_event(struct irqt_stat *irqs, int irq, u64 now)
 	return irqs->last_ts + irqs->ema_time[index];
 }
 
+static __always_inline int irq_timings_interval_index(u64 interval)
+{
+	/*
+	 * The PREDICTION_FACTOR increase the interval size for the
+	 * array of exponential average.
+	 */
+	u64 interval_us = (interval >> 10) / PREDICTION_FACTOR;
+
+	return likely(interval_us) ? ilog2(interval_us) : 0;
+}
+
+static __always_inline void __irq_timings_store(int irq, struct irqt_stat *irqs,
+						u64 interval)
+{
+	int index;
+
+	/*
+	 * Get the index in the ema table for this interrupt.
+	 */
+	index = irq_timings_interval_index(interval);
+
+	/*
+	 * Store the index as an element of the pattern in another
+	 * circular array.
+	 */
+	irqs->circ_timings[irqs->count & IRQ_TIMINGS_MASK] = index;
+
+	irqs->ema_time[index] = irq_timings_ema_new(interval,
+						    irqs->ema_time[index]);
+
+	irqs->count++;
+}
+
 static inline void irq_timings_store(int irq, struct irqt_stat *irqs, u64 ts)
 {
 	u64 old_ts = irqs->last_ts;
 	u64 interval;
-	int index;
 
 	/*
 	 * The timestamps are absolute time values, we need to compute
@@ -465,24 +497,7 @@ static inline void irq_timings_store(int irq, struct irqt_stat *irqs, u64 ts)
 		return;
 	}
 
-	/*
-	 * Get the index in the ema table for this interrupt. The
-	 * PREDICTION_FACTOR increase the interval size for the array
-	 * of exponential average.
-	 */
-	index = likely(interval) ?
-		ilog2((interval >> 10) / PREDICTION_FACTOR) : 0;
-
-	/*
-	 * Store the index as an element of the pattern in another
-	 * circular array.
-	 */
-	irqs->circ_timings[irqs->count & IRQ_TIMINGS_MASK] = index;
-
-	irqs->ema_time[index] = irq_timings_ema_new(interval,
-						    irqs->ema_time[index]);
-
-	irqs->count++;
+	__irq_timings_store(irq, irqs, interval);
 }
 
 /**