[PATCH 6.6 130/299] xen/events: drop xen_allocate_irqs_dynamic()

Greg Kroah-Hartman
2024-02-27T13:54:01Z

From: Juergen Gross <jgross@suse.com>

[ Upstream commit 5dd9ad32d7758b1a76742f394acf0eb3ac8a636a ]

Instead of having a common function for allocating a single IRQ or a
consecutive number of IRQs, split up the functionality into the callers
of xen_allocate_irqs_dynamic().

This allows to handle any allocation error in xen_irq_init() gracefully
instead of panicing the system. Let xen_irq_init() return the irq_info
pointer or NULL in case of an allocation error.

Additionally set the IRQ into irq_info already at allocation time, as
otherwise the IRQ would be '0' (which is a valid IRQ number) until
being set.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/xen/events/events_base.c | 74 +++++++++++++++++++-------------
1 file changed, 44 insertions(+), 30 deletions(-)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index d3d7501628381..4dfd68382465b 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -304,6 +304,13 @@ static void channels_on_cpu_inc(struct irq_info *info)
info->is_accounted = 1;
}

+static void xen_irq_free_desc(unsigned int irq)
+{
+ /* Legacy IRQ descriptors are managed by the arch. */
+ if (irq >= nr_legacy_irqs())
+ irq_free_desc(irq);
+}
+
static void delayed_free_irq(struct work_struct *work)
{
struct irq_info *info = container_of(to_rcu_work(work), struct irq_info,
@@ -315,9 +322,7 @@ static void delayed_free_irq(struct work_struct *work)

kfree(info);

- /* Legacy IRQ descriptors are managed by the arch. */
- if (irq >= nr_legacy_irqs())
- irq_free_desc(irq);
+ xen_irq_free_desc(irq);
}

/* Constructors for packed IRQ information. */
@@ -332,7 +337,6 @@ static int xen_irq_info_common_setup(struct irq_info *info,
BUG_ON(info->type != IRQT_UNBOUND && info->type != type);

info->type = type;
- info->irq = irq;
info->evtchn = evtchn;
info->cpu = cpu;
info->mask_reason = EVT_MASK_REASON_EXPLICIT;
@@ -733,47 +737,45 @@ void xen_irq_lateeoi(unsigned int irq, unsigned int eoi_flags)
}
EXPORT_SYMBOL_GPL(xen_irq_lateeoi);

-static void xen_irq_init(unsigned irq)
+static struct irq_info *xen_irq_init(unsigned int irq)
{
struct irq_info *info;

info = kzalloc(sizeof(*info), GFP_KERNEL);
- if (info == NULL)
- panic("Unable to allocate metadata for IRQ%d\n", irq);
+ if (info) {
+ info->irq = irq;
+ info->type = IRQT_UNBOUND;
+ info->refcnt = -1;
+ INIT_RCU_WORK(&info->rwork, delayed_free_irq);

- info->type = IRQT_UNBOUND;
- info->refcnt = -1;
- INIT_RCU_WORK(&info->rwork, delayed_free_irq);
+ set_info_for_irq(irq, info);
+ /*
+ * Interrupt affinity setting can be immediate. No point
+ * in delaying it until an interrupt is handled.
+ */
+ irq_set_status_flags(irq, IRQ_MOVE_PCNTXT);

- set_info_for_irq(irq, info);
- /*
- * Interrupt affinity setting can be immediate. No point
- * in delaying it until an interrupt is handled.
- */
- irq_set_status_flags(irq, IRQ_MOVE_PCNTXT);
+ INIT_LIST_HEAD(&info->eoi_list);
+ list_add_tail(&info->list, &xen_irq_list_head);
+ }

- INIT_LIST_HEAD(&info->eoi_list);
- list_add_tail(&info->list, &xen_irq_list_head);
+ return info;
}

-static int __must_check xen_allocate_irqs_dynamic(int nvec)
+static inline int __must_check xen_allocate_irq_dynamic(void)
{
- int i, irq = irq_alloc_descs(-1, 0, nvec, -1);
+ int irq = irq_alloc_desc_from(0, -1);

if (irq >= 0) {
- for (i = 0; i < nvec; i++)
- xen_irq_init(irq + i);
+ if (!xen_irq_init(irq)) {
+ xen_irq_free_desc(irq);
+ irq = -1;
+ }
}

return irq;
}

-static inline int __must_check xen_allocate_irq_dynamic(void)
-{
-
- return xen_allocate_irqs_dynamic(1);
-}
-
static int __must_check xen_allocate_irq_gsi(unsigned gsi)
{
int irq;
@@ -793,7 +795,10 @@ static int __must_check xen_allocate_irq_gsi(unsigned gsi)
else
irq = irq_alloc_desc_at(gsi, -1);

- xen_irq_init(irq);
+ if (!xen_irq_init(irq)) {
+ xen_irq_free_desc(irq);
+ irq = -1;
+ }

return irq;
}
@@ -963,6 +968,11 @@ static void __unbind_from_irq(unsigned int irq)
evtchn_port_t evtchn = evtchn_from_irq(irq);
struct irq_info *info = info_for_irq(irq);

+ if (!info) {
+ xen_irq_free_desc(irq);
+ return;
+ }
+
if (info->refcnt > 0) {
info->refcnt--;
if (info->refcnt != 0)
@@ -1101,11 +1111,14 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,

mutex_lock(&irq_mapping_update_lock);

- irq = xen_allocate_irqs_dynamic(nvec);
+ irq = irq_alloc_descs(-1, 0, nvec, -1);
if (irq < 0)
goto out;

for (i = 0; i < nvec; i++) {
+ if (!xen_irq_init(irq + i))
+ goto error_irq;
+
irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);

ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
@@ -1753,6 +1766,7 @@ void rebind_evtchn_irq(evtchn_port_t evtchn, int irq)
so there should be a proper type */
BUG_ON(info->type == IRQT_UNBOUND);

+ info->irq = irq;
(void)xen_irq_info_evtchn_setup(irq, evtchn, NULL);

mutex_unlock(&irq_mapping_update_lock);
--
2.43.0