powerpc/64: Cleanup __check_irq_replay()

Move the clearing of irq_happened bits into the condition where they
were found to be set. This reduces instruction count slightly, and
reduces stores into irq_happened.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/irq.c

@@ -143,9 +143,10 @@ notrace unsigned int __check_irq_replay(void)
 	 */
 	unsigned char happened = local_paca->irq_happened;
 
-	/* Clear bit 0 which we wouldn't clear otherwise */
-	local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
 	if (happened & PACA_IRQ_HARD_DIS) {
+		/* Clear bit 0 which we wouldn't clear otherwise */
+		local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+
 		/*
 		 * We may have missed a decrementer interrupt if hard disabled.
 		 * Check the decrementer register in case we had a rollover
@@ -173,39 +174,39 @@ notrace unsigned int __check_irq_replay(void)
 	 * This is a higher priority interrupt than the others, so
 	 * replay it first.
 	 */
-	local_paca->irq_happened &= ~PACA_IRQ_HMI;
-	if (happened & PACA_IRQ_HMI)
+	if (happened & PACA_IRQ_HMI) {
+		local_paca->irq_happened &= ~PACA_IRQ_HMI;
 		return 0xe60;
+	}
 
-	/*
-	 * We may have missed a decrementer interrupt. We check the
-	 * decrementer itself rather than the paca irq_happened field
-	 * in case we also had a rollover while hard disabled
-	 */
-	local_paca->irq_happened &= ~PACA_IRQ_DEC;
-	if (happened & PACA_IRQ_DEC)
+	if (happened & PACA_IRQ_DEC) {
+		local_paca->irq_happened &= ~PACA_IRQ_DEC;
 		return 0x900;
+	}
 
-	/* Finally check if an external interrupt happened */
-	local_paca->irq_happened &= ~PACA_IRQ_EE;
-	if (happened & PACA_IRQ_EE)
+	if (happened & PACA_IRQ_EE) {
+		local_paca->irq_happened &= ~PACA_IRQ_EE;
 		return 0x500;
+	}
 
 #ifdef CONFIG_PPC_BOOK3E
-	/* Finally check if an EPR external interrupt happened
-	 * this bit is typically set if we need to handle another
-	 * "edge" interrupt from within the MPIC "EPR" handler
+	/*
+	 * Check if an EPR external interrupt happened this bit is typically
+	 * set if we need to handle another "edge" interrupt from within the
+	 * MPIC "EPR" handler.
 	 */
-	local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
-	if (happened & PACA_IRQ_EE_EDGE)
+	if (happened & PACA_IRQ_EE_EDGE) {
+		local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
 		return 0x500;
+	}
 
-	local_paca->irq_happened &= ~PACA_IRQ_DBELL;
-	if (happened & PACA_IRQ_DBELL)
+	if (happened & PACA_IRQ_DBELL) {
+		local_paca->irq_happened &= ~PACA_IRQ_DBELL;
 		return 0x280;
+	}
 #else
-	local_paca->irq_happened &= ~PACA_IRQ_DBELL;
 	if (happened & PACA_IRQ_DBELL) {
+		local_paca->irq_happened &= ~PACA_IRQ_DBELL;
 		if (cpu_has_feature(CPU_FTR_HVMODE))
 			return 0xe80;
 		return 0xa00;