xen/events: allow setup of irq_info to fail

The FIFO-based event ABI requires additional setup of newly bound
events (it may need to expand the event array) and this setup may
fail.

xen_irq_info_common_init() is a useful place to put this setup so
allow this call to fail.  This call and the other similar calls are
renamed to be *_setup() to reflect that they may now fail.

This failure can only occur with new event channels not on rebind.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 7c7b744..4f7d94a 100644 (file)
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -99,7 +99,7 @@ struct irq_info *info_for_irq(unsigned irq)
 }
 
 /* Constructors for packed IRQ information. */
-static void xen_irq_info_common_init(struct irq_info *info,
+static int xen_irq_info_common_setup(struct irq_info *info,
                                     unsigned irq,
                                     enum xen_irq_type type,
                                     unsigned short evtchn,
@@ -116,45 +116,47 @@ static void xen_irq_info_common_init(struct irq_info *info,
        evtchn_to_irq[evtchn] = irq;
 
        irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
+
+       return 0;
 }
 
-static void xen_irq_info_evtchn_init(unsigned irq,
+static int xen_irq_info_evtchn_setup(unsigned irq,
                                     unsigned short evtchn)
 {
        struct irq_info *info = info_for_irq(irq);
 
-       xen_irq_info_common_init(info, irq, IRQT_EVTCHN, evtchn, 0);
+       return xen_irq_info_common_setup(info, irq, IRQT_EVTCHN, evtchn, 0);
 }
 
-static void xen_irq_info_ipi_init(unsigned cpu,
+static int xen_irq_info_ipi_setup(unsigned cpu,
                                  unsigned irq,
                                  unsigned short evtchn,
                                  enum ipi_vector ipi)
 {
        struct irq_info *info = info_for_irq(irq);
 
-       xen_irq_info_common_init(info, irq, IRQT_IPI, evtchn, 0);
-
        info->u.ipi = ipi;
 
        per_cpu(ipi_to_irq, cpu)[ipi] = irq;
+
+       return xen_irq_info_common_setup(info, irq, IRQT_IPI, evtchn, 0);
 }
 
-static void xen_irq_info_virq_init(unsigned cpu,
+static int xen_irq_info_virq_setup(unsigned cpu,
                                   unsigned irq,
                                   unsigned short evtchn,
                                   unsigned short virq)
 {
        struct irq_info *info = info_for_irq(irq);
 
-       xen_irq_info_common_init(info, irq, IRQT_VIRQ, evtchn, 0);
-
        info->u.virq = virq;
 
        per_cpu(virq_to_irq, cpu)[virq] = irq;
+
+       return xen_irq_info_common_setup(info, irq, IRQT_VIRQ, evtchn, 0);
 }
 
-static void xen_irq_info_pirq_init(unsigned irq,
+static int xen_irq_info_pirq_setup(unsigned irq,
                                   unsigned short evtchn,
                                   unsigned short pirq,
                                   unsigned short gsi,
@@ -163,12 +165,12 @@ static void xen_irq_info_pirq_init(unsigned irq,
 {
        struct irq_info *info = info_for_irq(irq);
 
-       xen_irq_info_common_init(info, irq, IRQT_PIRQ, evtchn, 0);
-
        info->u.pirq.pirq = pirq;
        info->u.pirq.gsi = gsi;
        info->u.pirq.domid = domid;
        info->u.pirq.flags = flags;
+
+       return xen_irq_info_common_setup(info, irq, IRQT_PIRQ, evtchn, 0);
 }
 
 /*
@@ -521,6 +523,47 @@ int xen_irq_from_gsi(unsigned gsi)
 }
 EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
 
+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);
+
+       if (info->refcnt > 0) {
+               info->refcnt--;
+               if (info->refcnt != 0)
+                       return;
+       }
+
+       if (VALID_EVTCHN(evtchn)) {
+               close.port = evtchn;
+               if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
+                       BUG();
+
+               switch (type_from_irq(irq)) {
+               case IRQT_VIRQ:
+                       per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
+                               [virq_from_irq(irq)] = -1;
+                       break;
+               case IRQT_IPI:
+                       per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
+                               [ipi_from_irq(irq)] = -1;
+                       break;
+               default:
+                       break;
+               }
+
+               /* Closed ports are implicitly re-bound to VCPU0. */
+               bind_evtchn_to_cpu(evtchn, 0);
+
+               evtchn_to_irq[evtchn] = -1;
+       }
+
+       BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);
+
+       xen_free_irq(irq);
+}
+
 /*
  * Do not make any assumptions regarding the relationship between the
  * IRQ number returned here and the Xen pirq argument.
@@ -536,6 +579,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 {
        int irq = -1;
        struct physdev_irq irq_op;
+       int ret;
 
        mutex_lock(&irq_mapping_update_lock);
 
@@ -563,8 +607,13 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
                goto out;
        }
 
-       xen_irq_info_pirq_init(irq, 0, pirq, gsi, DOMID_SELF,
+       ret = xen_irq_info_pirq_setup(irq, 0, pirq, gsi, DOMID_SELF,
                               shareable ? PIRQ_SHAREABLE : 0);
+       if (ret < 0) {
+               __unbind_from_irq(irq);
+               irq = ret;
+               goto out;
+       }
 
        pirq_query_unmask(irq);
        /* We try to use the handler with the appropriate semantic for the
@@ -624,7 +673,9 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
        irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
                        name);
 
-       xen_irq_info_pirq_init(irq, 0, pirq, 0, domid, 0);
+       ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
+       if (ret < 0)
+               goto error_irq;
        ret = irq_set_msi_desc(irq, msidesc);
        if (ret < 0)
                goto error_irq;
@@ -632,8 +683,8 @@ out:
        mutex_unlock(&irq_mapping_update_lock);
        return irq;
 error_irq:
+       __unbind_from_irq(irq);
        mutex_unlock(&irq_mapping_update_lock);
-       xen_free_irq(irq);
        return ret;
 }
 #endif
@@ -703,9 +754,11 @@ int xen_pirq_from_irq(unsigned irq)
        return pirq_from_irq(irq);
 }
 EXPORT_SYMBOL_GPL(xen_pirq_from_irq);
+
 int bind_evtchn_to_irq(unsigned int evtchn)
 {
        int irq;
+       int ret;
 
        mutex_lock(&irq_mapping_update_lock);
 
@@ -719,7 +772,12 @@ int bind_evtchn_to_irq(unsigned int evtchn)
                irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
                                              handle_edge_irq, "event");
 
-               xen_irq_info_evtchn_init(irq, evtchn);
+               ret = xen_irq_info_evtchn_setup(irq, evtchn);
+               if (ret < 0) {
+                       __unbind_from_irq(irq);
+                       irq = ret;
+                       goto out;
+               }
        } else {
                struct irq_info *info = info_for_irq(irq);
                WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
@@ -736,6 +794,7 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 {
        struct evtchn_bind_ipi bind_ipi;
        int evtchn, irq;
+       int ret;
 
        mutex_lock(&irq_mapping_update_lock);
 
@@ -755,8 +814,12 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
                        BUG();
                evtchn = bind_ipi.port;
 
-               xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
-
+               ret = xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
+               if (ret < 0) {
+                       __unbind_from_irq(irq);
+                       irq = ret;
+                       goto out;
+               }
                bind_evtchn_to_cpu(evtchn, cpu);
        } else {
                struct irq_info *info = info_for_irq(irq);
@@ -835,7 +898,12 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
                        evtchn = ret;
                }
 
-               xen_irq_info_virq_init(cpu, irq, evtchn, virq);
+               ret = xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
+               if (ret < 0) {
+                       __unbind_from_irq(irq);
+                       irq = ret;
+                       goto out;
+               }
 
                bind_evtchn_to_cpu(evtchn, cpu);
        } else {
@@ -851,50 +919,8 @@ out:
 
 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);
-
-       if (WARN_ON(!info))
-               return;
-
        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)
-                       BUG();
-
-               switch (type_from_irq(irq)) {
-               case IRQT_VIRQ:
-                       per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
-                               [virq_from_irq(irq)] = -1;
-                       break;
-               case IRQT_IPI:
-                       per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
-                               [ipi_from_irq(irq)] = -1;
-                       break;
-               default:
-                       break;
-               }
-
-               /* Closed ports are implicitly re-bound to VCPU0. */
-               bind_evtchn_to_cpu(evtchn, 0);
-
-               evtchn_to_irq[evtchn] = -1;
-       }
-
-       BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);
-
-       xen_free_irq(irq);
-
- done:
+       __unbind_from_irq(irq);
        mutex_unlock(&irq_mapping_update_lock);
 }
 
@@ -1142,7 +1168,7 @@ void rebind_evtchn_irq(int evtchn, int irq)
           so there should be a proper type */
        BUG_ON(info->type == IRQT_UNBOUND);
 
-       xen_irq_info_evtchn_init(irq, evtchn);
+       (void)xen_irq_info_evtchn_setup(irq, evtchn);
 
        mutex_unlock(&irq_mapping_update_lock);
 
@@ -1317,7 +1343,7 @@ static void restore_cpu_virqs(unsigned int cpu)
                evtchn = bind_virq.port;
 
                /* Record the new mapping. */
-               xen_irq_info_virq_init(cpu, irq, evtchn, virq);
+               (void)xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
                bind_evtchn_to_cpu(evtchn, cpu);
        }
 }
@@ -1341,7 +1367,7 @@ static void restore_cpu_ipis(unsigned int cpu)
                evtchn = bind_ipi.port;
 
                /* Record the new mapping. */
-               xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
+               (void)xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
                bind_evtchn_to_cpu(evtchn, cpu);
        }
 }