Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
Linus Torvalds [Fri, 26 Mar 2010 22:09:06 +0000 (15:09 -0700)]
* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: Move two IRQ functions from .init.text to .text
  genirq: Protect access to irq_desc->action in can_request_irq()
  genirq: Prevent oneshot irq thread race

kernel/irq/chip.c
kernel/irq/manage.c

index 42ec11b..b7091d5 100644 (file)
@@ -359,6 +359,23 @@ static inline void mask_ack_irq(struct irq_desc *desc, int irq)
                if (desc->chip->ack)
                        desc->chip->ack(irq);
        }
+       desc->status |= IRQ_MASKED;
+}
+
+static inline void mask_irq(struct irq_desc *desc, int irq)
+{
+       if (desc->chip->mask) {
+               desc->chip->mask(irq);
+               desc->status |= IRQ_MASKED;
+       }
+}
+
+static inline void unmask_irq(struct irq_desc *desc, int irq)
+{
+       if (desc->chip->unmask) {
+               desc->chip->unmask(irq);
+               desc->status &= ~IRQ_MASKED;
+       }
 }
 
 /*
@@ -484,10 +501,8 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
        raw_spin_lock(&desc->lock);
        desc->status &= ~IRQ_INPROGRESS;
 
-       if (unlikely(desc->status & IRQ_ONESHOT))
-               desc->status |= IRQ_MASKED;
-       else if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
-               desc->chip->unmask(irq);
+       if (!(desc->status & (IRQ_DISABLED | IRQ_ONESHOT)))
+               unmask_irq(desc, irq);
 out_unlock:
        raw_spin_unlock(&desc->lock);
 }
@@ -524,8 +539,7 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
        action = desc->action;
        if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
                desc->status |= IRQ_PENDING;
-               if (desc->chip->mask)
-                       desc->chip->mask(irq);
+               mask_irq(desc, irq);
                goto out;
        }
 
@@ -593,7 +607,7 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
                irqreturn_t action_ret;
 
                if (unlikely(!action)) {
-                       desc->chip->mask(irq);
+                       mask_irq(desc, irq);
                        goto out_unlock;
                }
 
@@ -605,8 +619,7 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
                if (unlikely((desc->status &
                               (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
                              (IRQ_PENDING | IRQ_MASKED))) {
-                       desc->chip->unmask(irq);
-                       desc->status &= ~IRQ_MASKED;
+                       unmask_irq(desc, irq);
                }
 
                desc->status &= ~IRQ_PENDING;
@@ -716,7 +729,7 @@ set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
        __set_irq_handler(irq, handle, 0, name);
 }
 
-void __init set_irq_noprobe(unsigned int irq)
+void set_irq_noprobe(unsigned int irq)
 {
        struct irq_desc *desc = irq_to_desc(irq);
        unsigned long flags;
@@ -731,7 +744,7 @@ void __init set_irq_noprobe(unsigned int irq)
        raw_spin_unlock_irqrestore(&desc->lock, flags);
 }
 
-void __init set_irq_probe(unsigned int irq)
+void set_irq_probe(unsigned int irq)
 {
        struct irq_desc *desc = irq_to_desc(irq);
        unsigned long flags;
index eb6078c..398fda1 100644 (file)
@@ -382,6 +382,7 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
 {
        struct irq_desc *desc = irq_to_desc(irq);
        struct irqaction *action;
+       unsigned long flags;
 
        if (!desc)
                return 0;
@@ -389,11 +390,14 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
        if (desc->status & IRQ_NOREQUEST)
                return 0;
 
+       raw_spin_lock_irqsave(&desc->lock, flags);
        action = desc->action;
        if (action)
                if (irqflags & action->flags & IRQF_SHARED)
                        action = NULL;
 
+       raw_spin_unlock_irqrestore(&desc->lock, flags);
+
        return !action;
 }
 
@@ -483,8 +487,26 @@ static int irq_wait_for_interrupt(struct irqaction *action)
  */
 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
 {
+again:
        chip_bus_lock(irq, desc);
        raw_spin_lock_irq(&desc->lock);
+
+       /*
+        * Implausible though it may be we need to protect us against
+        * the following scenario:
+        *
+        * The thread is faster done than the hard interrupt handler
+        * on the other CPU. If we unmask the irq line then the
+        * interrupt can come in again and masks the line, leaves due
+        * to IRQ_INPROGRESS and the irq line is masked forever.
+        */
+       if (unlikely(desc->status & IRQ_INPROGRESS)) {
+               raw_spin_unlock_irq(&desc->lock);
+               chip_bus_sync_unlock(irq, desc);
+               cpu_relax();
+               goto again;
+       }
+
        if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
                desc->status &= ~IRQ_MASKED;
                desc->chip->unmask(irq);