[RFC PATCH v2 2/2] genirq: Avoid unnecessary low level irq function calls

[Jeffy Chen]

Check irq state in enable/disable/unmask/mask_irq to avoid unnecessary
low level irq function calls.

Suggested-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Jeffy Chen <jeffy.c...@rock-chips.com>
---

Changes in v2:
Remove unnecessary started state check.

 kernel/irq/chip.c | 53 +++++++++++++++++++++++++++++++++--------------------
 1 file changed, 33 insertions(+), 20 deletions(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 8a5b597..7e8a35c 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -247,22 +247,32 @@ void irq_shutdown(struct irq_desc *desc)
 
 void irq_enable(struct irq_desc *desc)
 {
-       irq_state_clr_disabled(desc);
-       if (desc->irq_data.chip->irq_enable)
-               desc->irq_data.chip->irq_enable(&desc->irq_data);
-       else
-               desc->irq_data.chip->irq_unmask(&desc->irq_data);
-       irq_state_clr_masked(desc);
+       if (!irqd_irq_disabled(&desc->irq_data)) {
+               unmask_irq(desc);
+       } else {
+               irq_state_clr_disabled(desc);
+               if (desc->irq_data.chip->irq_enable) {
+                       desc->irq_data.chip->irq_enable(&desc->irq_data);
+                       irq_state_clr_masked(desc);
+               } else {
+                       unmask_irq(desc);
+               }
+       }
 }
 
 static void __irq_disable(struct irq_desc *desc, bool mask)
 {
-       irq_state_set_disabled(desc);
-       if (desc->irq_data.chip->irq_disable) {
-               desc->irq_data.chip->irq_disable(&desc->irq_data);
-               irq_state_set_masked(desc);
-       } else if (mask) {
-               mask_irq(desc);
+       if (irqd_irq_disabled(&desc->irq_data)) {
+               if (mask)
+                       mask_irq(desc);
+       } else {
+               irq_state_set_disabled(desc);
+               if (desc->irq_data.chip->irq_disable) {
+                       desc->irq_data.chip->irq_disable(&desc->irq_data);
+                       irq_state_set_masked(desc);
+               } else if (mask) {
+                       mask_irq(desc);
+               }
        }
 }
 
@@ -311,18 +321,21 @@ void irq_percpu_disable(struct irq_desc *desc, unsigned 
int cpu)
 
 static inline void mask_ack_irq(struct irq_desc *desc)
 {
-       if (desc->irq_data.chip->irq_mask_ack)
+       if (desc->irq_data.chip->irq_mask_ack) {
                desc->irq_data.chip->irq_mask_ack(&desc->irq_data);
-       else {
-               desc->irq_data.chip->irq_mask(&desc->irq_data);
+               irq_state_set_masked(desc);
+       } else {
+               mask_irq(desc);
                if (desc->irq_data.chip->irq_ack)
                        desc->irq_data.chip->irq_ack(&desc->irq_data);
        }
-       irq_state_set_masked(desc);
 }
 
 void mask_irq(struct irq_desc *desc)
 {
+       if (irqd_irq_masked(&desc->irq_data))
+               return;
+
        if (desc->irq_data.chip->irq_mask) {
                desc->irq_data.chip->irq_mask(&desc->irq_data);
                irq_state_set_masked(desc);
@@ -331,6 +344,9 @@ void mask_irq(struct irq_desc *desc)
 
 void unmask_irq(struct irq_desc *desc)
 {
+       if (!irqd_irq_masked(&desc->irq_data))
+               return;
+
        if (desc->irq_data.chip->irq_unmask) {
                desc->irq_data.chip->irq_unmask(&desc->irq_data);
                irq_state_clr_masked(desc);
@@ -344,10 +360,7 @@ void unmask_threaded_irq(struct irq_desc *desc)
        if (chip->flags & IRQCHIP_EOI_THREADED)
                chip->irq_eoi(&desc->irq_data);
 
-       if (chip->irq_unmask) {
-               chip->irq_unmask(&desc->irq_data);
-               irq_state_clr_masked(desc);
-       }
+       unmask_irq(desc);
 }
 
 /*
-- 
2.1.4