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-rw-r--r--drivers/xen/events.c74
-rw-r--r--drivers/xen/evtchn.c2
-rw-r--r--include/xen/events.h7
3 files changed, 81 insertions, 2 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6e075cd..a3bcd61 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -87,6 +87,7 @@ enum xen_irq_type {
*/
struct irq_info {
struct list_head list;
+ int refcnt;
enum xen_irq_type type; /* type */
unsigned irq;
unsigned short evtchn; /* event channel */
@@ -406,6 +407,7 @@ static void xen_irq_init(unsigned irq)
panic("Unable to allocate metadata for IRQ%d\n", irq);
info->type = IRQT_UNBOUND;
+ info->refcnt = -1;
irq_set_handler_data(irq, info);
@@ -469,6 +471,8 @@ static void xen_free_irq(unsigned irq)
irq_set_handler_data(irq, NULL);
+ WARN_ON(info->refcnt > 0);
+
kfree(info);
/* Legacy IRQ descriptors are managed by the arch. */
@@ -637,7 +641,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
if (irq != -1) {
printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
irq, gsi);
- goto out; /* XXX need refcount? */
+ goto out;
}
irq = xen_allocate_irq_gsi(gsi);
@@ -939,9 +943,16 @@ static void unbind_from_irq(unsigned int irq)
{
struct evtchn_close close;
int evtchn = evtchn_from_irq(irq);
+ struct irq_info *info = irq_get_handler_data(irq);
mutex_lock(&irq_mapping_update_lock);
+ if (info->refcnt > 0) {
+ info->refcnt--;
+ if (info->refcnt != 0)
+ goto done;
+ }
+
if (VALID_EVTCHN(evtchn)) {
close.port = evtchn;
if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
@@ -970,6 +981,7 @@ static void unbind_from_irq(unsigned int irq)
xen_free_irq(irq);
+ done:
mutex_unlock(&irq_mapping_update_lock);
}
@@ -1065,6 +1077,66 @@ void unbind_from_irqhandler(unsigned int irq, void *dev_id)
}
EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
+int evtchn_make_refcounted(unsigned int evtchn)
+{
+ int irq = evtchn_to_irq[evtchn];
+ struct irq_info *info;
+
+ if (irq == -1)
+ return -ENOENT;
+
+ info = irq_get_handler_data(irq);
+
+ if (!info)
+ return -ENOENT;
+
+ WARN_ON(info->refcnt != -1);
+
+ info->refcnt = 1;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(evtchn_make_refcounted);
+
+int evtchn_get(unsigned int evtchn)
+{
+ int irq;
+ struct irq_info *info;
+ int err = -ENOENT;
+
+ mutex_lock(&irq_mapping_update_lock);
+
+ irq = evtchn_to_irq[evtchn];
+ if (irq == -1)
+ goto done;
+
+ info = irq_get_handler_data(irq);
+
+ if (!info)
+ goto done;
+
+ err = -EINVAL;
+ if (info->refcnt <= 0)
+ goto done;
+
+ info->refcnt++;
+ err = 0;
+ done:
+ mutex_unlock(&irq_mapping_update_lock);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(evtchn_get);
+
+void evtchn_put(unsigned int evtchn)
+{
+ int irq = evtchn_to_irq[evtchn];
+ if (WARN_ON(irq == -1))
+ return;
+ unbind_from_irq(irq);
+}
+EXPORT_SYMBOL_GPL(evtchn_put);
+
void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
{
int irq = per_cpu(ipi_to_irq, cpu)[vector];
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index dbc13e9..b1f60a0 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -268,7 +268,7 @@ static int evtchn_bind_to_user(struct per_user_data *u, int port)
rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, IRQF_DISABLED,
u->name, (void *)(unsigned long)port);
if (rc >= 0)
- rc = 0;
+ rc = evtchn_make_refcounted(port);
return rc;
}
diff --git a/include/xen/events.h b/include/xen/events.h
index d287997..0f77370 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -37,6 +37,13 @@ int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
*/
void unbind_from_irqhandler(unsigned int irq, void *dev_id);
+/*
+ * Allow extra references to event channels exposed to userspace by evtchn
+ */
+int evtchn_make_refcounted(unsigned int evtchn);
+int evtchn_get(unsigned int evtchn);
+void evtchn_put(unsigned int evtchn);
+
void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector);
int resend_irq_on_evtchn(unsigned int irq);
void rebind_evtchn_irq(int evtchn, int irq);
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