Merge branch 'linus' into irq/core

Reason: Get upstream fixes integrated before further modifications.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 75 insertions, 19 deletions

diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c
index 342d8f44e401..0119b9d467ae 100644
--- a/kernel/irq/autoprobe.c
+++ b/kernel/irq/autoprobe.c
@@ -53,7 +53,7 @@ unsigned long probe_irq_on(void)
                         if (desc->irq_data.chip->irq_set_type)
                                 desc->irq_data.chip->irq_set_type(&desc->irq_data,
                                                          IRQ_TYPE_PROBE);
-                        irq_startup(desc);
+                        irq_startup(desc, false);
                 }
                 raw_spin_unlock_irq(&desc->lock);
         }
@@ -70,7 +70,7 @@ unsigned long probe_irq_on(void)
                 raw_spin_lock_irq(&desc->lock);
                 if (!desc->action && irq_settings_can_probe(desc)) {
                         desc->istate |= IRQS_AUTODETECT | IRQS_WAITING;
-                        if (irq_startup(desc))
+                        if (irq_startup(desc, false))
                                 desc->istate |= IRQS_PENDING;
                 }
                 raw_spin_unlock_irq(&desc->lock);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 4dbc9c9d641b..25784d630a12 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -156,19 +156,22 @@ static void irq_state_set_masked(struct irq_desc *desc)
         irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
 }
 
-int irq_startup(struct irq_desc *desc)
+int irq_startup(struct irq_desc *desc, bool resend)
 {
+        int ret = 0;
+
         irq_state_clr_disabled(desc);
         desc->depth = 0;
 
         if (desc->irq_data.chip->irq_startup) {
-                int ret = desc->irq_data.chip->irq_startup(&desc->irq_data);
+                ret = desc->irq_data.chip->irq_startup(&desc->irq_data);
                 irq_state_clr_masked(desc);
-                return ret;
+        } else {
+                irq_enable(desc);
         }
-
-        irq_enable(desc);
-        return 0;
+        if (resend)
+                check_irq_resend(desc, desc->irq_data.irq);
+        return ret;
 }
 
 void irq_shutdown(struct irq_desc *desc)
@@ -329,6 +332,24 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(handle_simple_irq);
 
+/*
+ * Called unconditionally from handle_level_irq() and only for oneshot
+ * interrupts from handle_fasteoi_irq()
+ */
+static void cond_unmask_irq(struct irq_desc *desc)
+{
+        /*
+         * We need to unmask in the following cases:
+         * - Standard level irq (IRQF_ONESHOT is not set)
+         * - 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)
+                unmask_irq(desc);
+}
+
 /**
  *      handle_level_irq - Level type irq handler
  *      @irq:   the interrupt number
@@ -361,8 +382,8 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
 
         handle_irq_event(desc);
 
-        if (!irqd_irq_disabled(&desc->irq_data) && !(desc->istate & IRQS_ONESHOT))
-                unmask_irq(desc);
+        cond_unmask_irq(desc);
+
 out_unlock:
         raw_spin_unlock(&desc->lock);
 }
@@ -416,6 +437,9 @@ 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);
+
 out_eoi:
         desc->irq_data.chip->irq_eoi(&desc->irq_data);
 out_unlock:
@@ -624,7 +648,7 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
                 irq_settings_set_noprobe(desc);
                 irq_settings_set_norequest(desc);
                 irq_settings_set_nothread(desc);
-                irq_startup(desc);
+                irq_startup(desc, true);
         }
 out:
         irq_put_desc_busunlock(desc, flags);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 5c233e0ea2c3..8e5c56b3b7d9 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -65,7 +65,7 @@ extern int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 extern void __disable_irq(struct irq_desc *desc, unsigned int irq, bool susp);
 extern void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume);
 
-extern int irq_startup(struct irq_desc *desc);
+extern int irq_startup(struct irq_desc *desc, bool resend);
 extern void irq_shutdown(struct irq_desc *desc);
 extern void irq_enable(struct irq_desc *desc);
 extern void irq_disable(struct irq_desc *desc);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index a94466db73b2..1786cf7dac54 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -979,6 +979,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 
                 /* add new interrupt at end of irq queue */
                 do {
+                        /*
+                         * Or all existing action->thread_mask bits,
+                         * so we can find the next zero bit for this
+                         * new action.
+                         */
                         thread_mask |= old->thread_mask;
                         old_ptr = &old->next;
                         old = *old_ptr;
@@ -987,14 +992,41 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
         }
 
         /*
-         * Setup the thread mask for this irqaction. Unlikely to have
-         * 32 resp 64 irqs sharing one line, but who knows.
+         * Setup the thread mask for this irqaction for ONESHOT. For
+         * !ONESHOT irqs the thread mask is 0 so we can avoid a
+         * conditional in irq_wake_thread().
          */
-        if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
-                ret = -EBUSY;
-                goto out_mask;
+        if (new->flags & IRQF_ONESHOT) {
+                /*
+                 * Unlikely to have 32 resp 64 irqs sharing one line,
+                 * but who knows.
+                 */
+                if (thread_mask == ~0UL) {
+                        ret = -EBUSY;
+                        goto out_mask;
+                }
+                /*
+                 * The thread_mask for the action is or'ed to
+                 * desc->thread_active to indicate that the
+                 * IRQF_ONESHOT thread handler has been woken, but not
+                 * yet finished. The bit is cleared when a thread
+                 * completes. When all threads of a shared interrupt
+                 * line have completed desc->threads_active becomes
+                 * zero and the interrupt line is unmasked. See
+                 * handle.c:irq_wake_thread() for further information.
+                 *
+                 * If no thread is woken by primary (hard irq context)
+                 * interrupt handlers, then desc->threads_active is
+                 * also checked for zero to unmask the irq line in the
+                 * affected hard irq flow handlers
+                 * (handle_[fasteoi|level]_irq).
+                 *
+                 * The new action gets the first zero bit of
+                 * thread_mask assigned. See the loop above which or's
+                 * all existing action->thread_mask bits.
+                 */
+                new->thread_mask = 1 << ffz(thread_mask);
         }
-        new->thread_mask = 1 << ffz(thread_mask);
 
         if (!shared) {
                 init_waitqueue_head(&desc->wait_for_threads);
@@ -1021,7 +1053,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                         desc->istate |= IRQS_ONESHOT;
 
                 if (irq_settings_can_autoenable(desc))
-                        irq_startup(desc);
+                        irq_startup(desc, true);
                 else
                         /* Undo nested disables: */
                         desc->depth = 1;