generic: add irq_desc in function in parameter

So we could remove some duplicated calling to irq_desc

v2: make sure irq_desc in  init/main.c is not used without generic_hardirqs
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/irq_64.c

@@ -189,6 +189,7 @@ u64 arch_irq_stat(void)
 asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
+	struct irq_desc *desc;
 
 	/* high bit used in ret_from_ code  */
 	unsigned vector = ~regs->orig_ax;
@@ -202,8 +203,9 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
 	stack_overflow_check(regs);
 #endif
 
-	if (likely(__irq_to_desc(irq)))
-		generic_handle_irq(irq);
+	desc = __irq_to_desc(irq);
+	if (likely(desc))
+		generic_handle_irq_desc(irq, desc);
 	else {
 		if (!disable_apic)
 			ack_APIC_irq();

include/linux/irq.h

@@ -315,10 +315,8 @@ extern unsigned int __do_IRQ(unsigned int irq);
  * irqchip-style controller then we call the ->handle_irq() handler,
  * and it calls __do_IRQ() if it's attached to an irqtype-style controller.
  */
-static inline void generic_handle_irq(unsigned int irq)
+static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *desc)
 {
-	struct irq_desc *desc = irq_to_desc(irq);
-
 #ifdef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 	desc->handle_irq(irq, desc);
 #else
@@ -329,6 +327,11 @@ static inline void generic_handle_irq(unsigned int irq)
 #endif
 }
 
+static inline void generic_handle_irq(unsigned int irq)
+{
+	generic_handle_irq_desc(irq, irq_to_desc(irq));
+}
+
 /* Handling of unhandled and spurious interrupts: */
 extern void note_interrupt(unsigned int irq, struct irq_desc *desc,
 			   int action_ret);

init/main.c

@@ -590,6 +590,13 @@ void pre_alloc_dyn_array(void)
 		if (da->init_work)
 			da->init_work(da);
 	}
+#else
+#ifdef CONFIF_GENERIC_HARDIRQS
+	unsigned int i;
+
+	for (i = 0; i < NR_IRQS; i++)
+		irq_desc[i].irq = i;
+#endif
 #endif
 }
 

kernel/irq/handle.c

@@ -197,6 +197,21 @@ struct irq_desc *irq_to_desc(unsigned int irq)
 	 *  we run out of pre-allocate ones, allocate more
 	 */
 	printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
+	{
+		/* double check if some one mess up the list */
+		struct irq_desc *desc;
+		int count = 0;
+
+		desc = &sparse_irqs[0];
+		while (desc) {
+			printk(KERN_DEBUG "found irq_desc for irq %d\n", desc->irq);
+			if (desc->next)
+				printk(KERN_DEBUG "found irq_desc for irq %d and next will be irq %d\n", desc->irq, desc->next->irq);
+			desc = desc->next;
+			count++;
+		}
+		printk(KERN_DEBUG "all preallocted %d\n", count);
+	}
 
 	total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
 	if (after_bootmem)
@@ -221,6 +236,21 @@ struct irq_desc *irq_to_desc(unsigned int irq)
 
 	desc->irq = irq;
 	desc_pri->next = desc;
+	{
+		/* double check if some one mess up the list */
+		struct irq_desc *desc;
+		int count = 0;
+
+		desc = &sparse_irqs[0];
+		while (desc) {
+			printk(KERN_DEBUG "1 found irq_desc for irq %d\n", desc->irq);
+			if (desc->next)
+				printk(KERN_DEBUG "1 found irq_desc for irq %d and next will be irq %d\n", desc->irq, desc->next->irq);
+			desc = desc->next;
+			count++;
+		}
+		printk(KERN_DEBUG "1 all preallocted %d\n", count);
+	}
 
 	return desc;
 }