From: Thomas Gleixner <[email protected]>

This flag must be used in combination with handle_fasteoi_irq, when set
handle_fasteoi_irq will delay the calling of chip->irq_eoi until the threaded
handler has run.

Reviewed-by: Hans de Goede <[email protected]>
Tested-by: Hans de Goede <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>
---
 include/linux/irq.h    |  3 +++
 kernel/irq/chip.c      | 48 ++++++++++++++++++++++++++++++++++++++++--------
 kernel/irq/internals.h |  1 +
 kernel/irq/manage.c    |  2 +-
 4 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 7dc1003..0f036fb 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -349,6 +349,8 @@ struct irq_chip {
  * IRQCHIP_ONOFFLINE_ENABLED:  Only call irq_on/off_line callbacks
  *                             when irq enabled
  * IRQCHIP_SKIP_SET_WAKE:      Skip chip.irq_set_wake(), for this irq chip
+ * IRQCHIP_ONESHOT_SAFE:       One shot does not require mask/unmask
+ * IRQCHIP_EOI_THREADED:       Chip requires eoi() on unmask in threaded mode
  */
 enum {
        IRQCHIP_SET_TYPE_MASKED         = (1 <<  0),
@@ -357,6 +359,7 @@ enum {
        IRQCHIP_ONOFFLINE_ENABLED       = (1 <<  3),
        IRQCHIP_SKIP_SET_WAKE           = (1 <<  4),
        IRQCHIP_ONESHOT_SAFE            = (1 <<  5),
+       IRQCHIP_EOI_THREADED            = (1 <<  6),
 };
 
 /* This include will go away once we isolated irq_desc usage to core code */
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index dc04c16..6397df2 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -281,6 +281,19 @@ void unmask_irq(struct irq_desc *desc)
        }
 }
 
+void unmask_threaded_irq(struct irq_desc *desc)
+{
+       struct irq_chip *chip = desc->irq_data.chip;
+
+       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);
+       }
+}
+
 /*
  *     handle_nested_irq - Handle a nested irq from a irq thread
  *     @irq:   the interrupt number
@@ -435,6 +448,27 @@ static inline void preflow_handler(struct irq_desc *desc)
 static inline void preflow_handler(struct irq_desc *desc) { }
 #endif
 
+static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
+{
+       if (!(desc->istate & IRQS_ONESHOT)) {
+               chip->irq_eoi(&desc->irq_data);
+               return;
+       }
+       /*
+        * We need to unmask in the following cases:
+        * - Oneshot irq which did not wake the thread (caused by a
+        *   spurious interrupt or a primary handler handling it
+        *   completely).
+        */
+       if (!irqd_irq_disabled(&desc->irq_data) &&
+           irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot) {
+               chip->irq_eoi(&desc->irq_data);
+               unmask_irq(desc);
+       } else if (!(chip->flags & IRQCHIP_EOI_THREADED)) {
+               chip->irq_eoi(&desc->irq_data);
+       }
+}
+
 /**
  *     handle_fasteoi_irq - irq handler for transparent controllers
  *     @irq:   the interrupt number
@@ -448,6 +482,8 @@ static inline void preflow_handler(struct irq_desc *desc) { 
}
 void
 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 {
+       struct irq_chip *chip = desc->irq_data.chip;
+
        raw_spin_lock(&desc->lock);
 
        if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
@@ -473,18 +509,14 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc 
*desc)
        preflow_handler(desc);
        handle_irq_event(desc);
 
-       if (desc->istate & IRQS_ONESHOT)
-               cond_unmask_irq(desc);
+       cond_unmask_eoi_irq(desc, chip);
 
-out_eoi:
-       desc->irq_data.chip->irq_eoi(&desc->irq_data);
-out_unlock:
        raw_spin_unlock(&desc->lock);
        return;
 out:
-       if (!(desc->irq_data.chip->flags & IRQCHIP_EOI_IF_HANDLED))
-               goto out_eoi;
-       goto out_unlock;
+       if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+               chip->irq_eoi(&desc->irq_data);
+       raw_spin_unlock(&desc->lock);
 }
 
 /**
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 001fa5b..e98bb56 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -73,6 +73,7 @@ extern void irq_percpu_enable(struct irq_desc *desc, unsigned 
int cpu);
 extern void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu);
 extern void mask_irq(struct irq_desc *desc);
 extern void unmask_irq(struct irq_desc *desc);
+extern void unmask_threaded_irq(struct irq_desc *desc);
 
 extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr);
 
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 481a13c..9147fef 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -718,7 +718,7 @@ again:
 
        if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
            irqd_irq_masked(&desc->irq_data))
-               unmask_irq(desc);
+               unmask_threaded_irq(desc);
 
 out_unlock:
        raw_spin_unlock_irq(&desc->lock);
-- 
1.9.0

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