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xen/events: allow setup of irq_info to fail
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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>
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David Vrabel authored and Konrad Rzeszutek Wilk committed Jan 6, 2014
1 parent ab9a1cc commit 96d4c58
Showing 1 changed file with 91 additions and 65 deletions.
156 changes: 91 additions & 65 deletions drivers/xen/events/events_base.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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,
Expand All @@ -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);
}

/*
Expand Down Expand Up @@ -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.
Expand All @@ -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);

Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -624,16 +673,18 @@ 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;
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
Expand Down Expand Up @@ -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);

Expand All @@ -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);
Expand All @@ -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);

Expand All @@ -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);
Expand Down Expand Up @@ -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 {
Expand All @@ -851,50 +919,8 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)

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);
}

Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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);
}
}
Expand All @@ -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);
}
}
Expand Down

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