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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH for-4.5 7/8] xen/irq: Handle multiple action per IRQ
On 03/31/2014 04:53 PM, Ian Campbell wrote:
> On Mon, 2014-03-31 at 16:45 +0100, Julien Grall wrote:
>> On 02/19/2014 11:55 AM, Ian Campbell wrote:
>>> On Fri, 2014-01-24 at 16:43 +0000, Julien Grall wrote:
>>>> On ARM, it may happen (eg ARM SMMU) to setup multiple handler for the same
>>>> interrupt.
>>>
>>> Mention here that you are therefore creating a linked list of actions
>>> for each interrupt.
>>>
>>> If you use xen/list.h for this then you get a load of helpers and
>>> iterators which would save you open coding them.
>>
>> I've tried to use xen/list.h. The amount of code it's basically the same
>> and we I have to write open code to get the first element of the list
>
> Why? Can you post your WIP patch please for comparison.
Because:
- there is no helper to get the first element (__setup_irq)
- I need to use 2 variables to search for an element in a list as there
is
no way to know after the end of the loop if we found or not an element.
Below an incremental patch which change next field to a list (doesn't compile
and not finished):
diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 7ea4da8..f4f5b71 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -545,36 +545,33 @@ void release_irq(unsigned int irq, const void *dev_id)
{
struct irq_desc *desc;
unsigned long flags;
- struct irqaction *action, **action_ptr;
+ struct irqaction *action, *next;
desc = irq_to_desc(irq);
spin_lock_irqsave(&desc->lock,flags);
- desc->handler->shutdown(desc);
- action = desc->action;
- action_ptr = &desc->action;
- for ( ;; )
+ action = NULL;
+ list_for_each_entry(next, &desc->action, next)
{
- action = *action_ptr;
-
- if ( !action )
+ if ( next->dev_id == dev_id )
{
- printk(XENLOG_WARNING "Trying to free already-free IRQ %u\n", irq);
- return;
- }
-
- if ( action->dev_id == dev_id )
+ action = next;
break;
+ }
+ }
- action_ptr = &action->next;
+ if ( !action )
+ {
+ printk(XENLOG_WARNING "Trying to free already-free IRQ %u\n", irq);
+ return;
}
/* Found it - remove it from the action list */
- *action_ptr = action->next;
+ list_del_init(&action->next);
/* If this was the list action, shut down the IRQ */
- if ( !desc->action )
+ if ( list_empty(&desc->action) )
{
desc->handler->shutdown(desc);
desc->status &= ~IRQ_GUEST;
@@ -592,12 +589,10 @@ void release_irq(unsigned int irq, const void *dev_id)
static int __setup_irq(struct irq_desc *desc, struct irqaction *new,
unsigned int irqflags)
{
- struct irqaction *action = desc->action;
-
ASSERT(new != NULL);
/* Sanity check if the IRQ already have an action attached */
- if ( action != NULL )
+ if ( !list_empty(&desc->action) )
{
/* Check that IRQ is marked as shared */
if ( !(desc->status & IRQ_SHARED) || !(irqflags & IRQ_SHARED) )
@@ -610,8 +605,8 @@ static int __setup_irq(struct irq_desc *desc, struct
irqaction *new,
if ( irqflags & IRQ_SHARED )
desc->status |= IRQ_SHARED;
- new->next = desc->action;
- desc->action = new;
+ INIT_LIST_HEAD(&new->next);
+ list_add_tail(&new->next, &desc->action);
dsb(sy);
return 0;
diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
index d6f3500..8a9ae3d 100644
--- a/xen/arch/arm/irq.c
+++ b/xen/arch/arm/irq.c
@@ -56,6 +56,7 @@ irq_desc_t *__irq_to_desc(int irq)
int __init arch_init_one_irq_desc(struct irq_desc *desc)
{
desc->arch.type = DT_IRQ_TYPE_NONE;
+ INIT_LIST_HEAD(&desc->action);
return 0;
}
@@ -151,7 +152,6 @@ int request_irq(unsigned int irq,
void do_IRQ(struct cpu_user_regs *regs, unsigned int irq, int is_fiq)
{
struct irq_desc *desc = irq_to_desc(irq);
- struct irqaction *action = desc->action;
/* TODO: perfc_incr(irqs); */
@@ -162,7 +162,7 @@ void do_IRQ(struct cpu_user_regs *regs, unsigned int irq,
int is_fiq)
spin_lock(&desc->lock);
desc->handler->ack(desc);
- if ( action == NULL )
+ if ( list_empty(&desc->action) )
{
printk("Unknown %s %#3.3x\n",
is_fiq ? "FIQ" : "IRQ", irq);
@@ -171,6 +171,8 @@ void do_IRQ(struct cpu_user_regs *regs, unsigned int irq,
int is_fiq)
if ( desc->status & IRQ_GUEST )
{
+ struct irqaction *action = list_entry(&desc->action, struct irqaction,
+ next);
struct domain *d = action->dev_id;
desc->handler->end(desc);
@@ -194,16 +196,14 @@ void do_IRQ(struct cpu_user_regs *regs, unsigned int irq,
int is_fiq)
desc->status |= IRQ_INPROGRESS;
- action = desc->action;
while ( desc->status & IRQ_PENDING )
{
+ struct irqaction *action, *next;
+
desc->status &= ~IRQ_PENDING;
spin_unlock_irq(&desc->lock);
- do
- {
+ list_for_each_entry_safe(action, next, &desc->action, next)
action->handler(irq, action->dev_id, regs);
- action = action->next;
- } while ( action );
spin_lock_irq(&desc->lock);
}
diff --git a/xen/include/xen/irq.h b/xen/include/xen/irq.h
index 20548aa..a926554 100644
--- a/xen/include/xen/irq.h
+++ b/xen/include/xen/irq.h
@@ -17,7 +17,9 @@ struct irqaction {
const char *name;
void *dev_id;
bool_t free_on_release;
- struct irqaction *next;
+#ifdef CONFIG_ARM
+ struct list_head next;
+#endif
};
/*
@@ -73,7 +75,11 @@ typedef struct irq_desc {
unsigned int status; /* IRQ status */
hw_irq_controller *handler;
struct msi_desc *msi_desc;
+#ifdef CONFIG_ARM
+ struct list_head action; /* IRQ action list */
+#else
struct irqaction *action; /* IRQ action list */
+#endif
int irq;
spinlock_t lock;
struct arch_irq_desc arch;
--
Julien Grall
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