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drm/nouveau/core: split lock into list+exec and enable refcount locks

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This fixes a reported locking inversion when interacting with the DRM
core's vblank routines.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Ben Skeggs 2013-10-03 09:59:16 +10:00
parent 51cb4b392a
commit 15689c3c81
2 changed files with 34 additions and 30 deletions
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61
drivers/gpu/drm/nouveau/core/core/event.c
View file

@ -23,27 +23,19 @@
#include <core/os.h>
#include <core/event.h>
static void
nouveau_event_put_locked(struct nouveau_event *event, int index,
struct nouveau_eventh *handler)
{
if (__test_and_clear_bit(NVKM_EVENT_ENABLE, &handler->flags)) {
if (!--event->index[index].refs) {
if (event->disable)
event->disable(event, index);
}
list_del(&handler->head);
}
}
void
nouveau_event_put(struct nouveau_eventh *handler)
{
struct nouveau_event *event = handler->event;
unsigned long flags;
spin_lock_irqsave(&event->lock, flags);
nouveau_event_put_locked(handler->event, handler->index, handler);
spin_unlock_irqrestore(&event->lock, flags);
if (__test_and_clear_bit(NVKM_EVENT_ENABLE, &handler->flags)) {
spin_lock_irqsave(&event->refs_lock, flags);
if (!--event->index[handler->index].refs) {
if (event->disable)
event->disable(event, handler->index);
}
spin_unlock_irqrestore(&event->refs_lock, flags);
}
}
void
@ -51,22 +43,25 @@ nouveau_event_get(struct nouveau_eventh *handler)
{
struct nouveau_event *event = handler->event;
unsigned long flags;
spin_lock_irqsave(&event->lock, flags);
if (!__test_and_set_bit(NVKM_EVENT_ENABLE, &handler->flags)) {
list_add(&handler->head, &event->index[handler->index].list);
spin_lock_irqsave(&event->refs_lock, flags);
if (!event->index[handler->index].refs++) {
if (event->enable)
event->enable(event, handler->index);
}
spin_unlock_irqrestore(&event->refs_lock, flags);
}
spin_unlock_irqrestore(&event->lock, flags);
}
static void
nouveau_event_fini(struct nouveau_eventh *handler)
{
struct nouveau_event *event = handler->event;
unsigned long flags;
nouveau_event_put(handler);
spin_lock_irqsave(&event->list_lock, flags);
list_del(&handler->head);
spin_unlock_irqrestore(&event->list_lock, flags);
}
static int
@ -74,13 +69,20 @@ nouveau_event_init(struct nouveau_event *event, int index,
int (*func)(void *, int), void *priv,
struct nouveau_eventh *handler)
{
unsigned long flags;
if (index >= event->index_nr)
return -EINVAL;
handler->event = event;
handler->flags = 0;
handler->index = index;
handler->func = func;
handler->priv = priv;
spin_lock_irqsave(&event->list_lock, flags);
list_add_tail(&handler->head, &event->index[index].list);
spin_unlock_irqrestore(&event->list_lock, flags);
return 0;
}
@ -116,19 +118,19 @@ nouveau_event_ref(struct nouveau_eventh *handler, struct nouveau_eventh **ref)
void
nouveau_event_trigger(struct nouveau_event *event, int index)
{
struct nouveau_eventh *handler, *temp;
struct nouveau_eventh *handler;
unsigned long flags;
if (index >= event->index_nr)
if (WARN_ON(index >= event->index_nr))
return;
spin_lock_irqsave(&event->lock, flags);
list_for_each_entry_safe(handler, temp, &event->index[index].list, head) {
if (handler->func(handler->priv, index) == NVKM_EVENT_DROP) {
nouveau_event_put_locked(event, index, handler);
}
spin_lock_irqsave(&event->list_lock, flags);
list_for_each_entry(handler, &event->index[index].list, head) {
if (test_bit(NVKM_EVENT_ENABLE, &handler->flags) &&
handler->func(handler->priv, index) == NVKM_EVENT_DROP)
nouveau_event_put(handler);
}
spin_unlock_irqrestore(&event->lock, flags);
spin_unlock_irqrestore(&event->list_lock, flags);
}
void
@ -152,7 +154,8 @@ nouveau_event_create(int index_nr, struct nouveau_event **pevent)
if (!event)
return -ENOMEM;
spin_lock_init(&event->lock);
spin_lock_init(&event->list_lock);
spin_lock_init(&event->refs_lock);
for (i = 0; i < index_nr; i++)
INIT_LIST_HEAD(&event->index[i].list);
event->index_nr = index_nr;

3
drivers/gpu/drm/nouveau/core/include/core/event.h
View file

@ -18,7 +18,8 @@ struct nouveau_eventh {
};
struct nouveau_event {
spinlock_t lock;
spinlock_t list_lock;
spinlock_t refs_lock;
void *priv;
void (*enable)(struct nouveau_event *, int index);