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>

1 files changed, 91 insertions, 65 deletions

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 7c7b744cd13d..4f7d94abe82c 100644
--- 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);
         }
 }