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authorFrancisco Jerez <currojerez@riseup.net>2010-10-11 03:37:32 +0200
committerBen Skeggs <bskeggs@redhat.com>2010-11-18 14:38:22 +1000
commit7bb94d26ad62ca1d6b5e11db6e26425785cc46ac (patch)
tree7e05690c2fb37172ff1cfd82c130320daf13aa0e
parentcbab95db84f2a444d99bec77bac8b9b6ef20d11c (diff)
drm/nouveau: Avoid lock dependency between ramht and ramin spinlocks.
The ramht code called some gpuobj functions with the HARDIRQ-safe RAMHT spinlock held, this could potentially lead to a dead lock because ramin_lock is HARDIRQ-unsafe. Signed-off-by: Francisco Jerez <currojerez@riseup.net> Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
-rw-r--r--drivers/gpu/drm/nouveau/nouveau_ramht.c71
1 files changed, 44 insertions, 27 deletions
diff --git a/drivers/gpu/drm/nouveau/nouveau_ramht.c b/drivers/gpu/drm/nouveau/nouveau_ramht.c
index 7f16697cc96c..2d8580927ca4 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ramht.c
+++ b/drivers/gpu/drm/nouveau/nouveau_ramht.c
@@ -153,26 +153,42 @@ nouveau_ramht_insert(struct nouveau_channel *chan, u32 handle,
return -ENOMEM;
}
+static struct nouveau_ramht_entry *
+nouveau_ramht_remove_entry(struct nouveau_channel *chan, u32 handle)
+{
+ struct nouveau_ramht *ramht = chan ? chan->ramht : NULL;
+ struct nouveau_ramht_entry *entry;
+ unsigned long flags;
+
+ if (!ramht)
+ return NULL;
+
+ spin_lock_irqsave(&ramht->lock, flags);
+ list_for_each_entry(entry, &ramht->entries, head) {
+ if (entry->channel == chan &&
+ (!handle || entry->handle == handle)) {
+ list_del(&entry->head);
+ spin_unlock_irqrestore(&ramht->lock, flags);
+
+ return entry;
+ }
+ }
+ spin_unlock_irqrestore(&ramht->lock, flags);
+
+ return NULL;
+}
+
static void
-nouveau_ramht_remove_locked(struct nouveau_channel *chan, u32 handle)
+nouveau_ramht_remove_hash(struct nouveau_channel *chan, u32 handle)
{
struct drm_device *dev = chan->dev;
struct drm_nouveau_private *dev_priv = dev->dev_private;
struct nouveau_instmem_engine *instmem = &dev_priv->engine.instmem;
struct nouveau_gpuobj *ramht = chan->ramht->gpuobj;
- struct nouveau_ramht_entry *entry, *tmp;
+ unsigned long flags;
u32 co, ho;
- list_for_each_entry_safe(entry, tmp, &chan->ramht->entries, head) {
- if (entry->channel != chan || entry->handle != handle)
- continue;
-
- nouveau_gpuobj_ref(NULL, &entry->gpuobj);
- list_del(&entry->head);
- kfree(entry);
- break;
- }
-
+ spin_lock_irqsave(&chan->ramht->lock, flags);
co = ho = nouveau_ramht_hash_handle(chan, handle);
do {
if (nouveau_ramht_entry_valid(dev, ramht, co) &&
@@ -184,7 +200,7 @@ nouveau_ramht_remove_locked(struct nouveau_channel *chan, u32 handle)
nv_wo32(ramht, co + 0, 0x00000000);
nv_wo32(ramht, co + 4, 0x00000000);
instmem->flush(dev);
- return;
+ goto out;
}
co += 8;
@@ -194,17 +210,22 @@ nouveau_ramht_remove_locked(struct nouveau_channel *chan, u32 handle)
NV_ERROR(dev, "RAMHT entry not found. ch=%d, handle=0x%08x\n",
chan->id, handle);
+out:
+ spin_unlock_irqrestore(&chan->ramht->lock, flags);
}
void
nouveau_ramht_remove(struct nouveau_channel *chan, u32 handle)
{
- struct nouveau_ramht *ramht = chan->ramht;
- unsigned long flags;
+ struct nouveau_ramht_entry *entry;
- spin_lock_irqsave(&ramht->lock, flags);
- nouveau_ramht_remove_locked(chan, handle);
- spin_unlock_irqrestore(&ramht->lock, flags);
+ entry = nouveau_ramht_remove_entry(chan, handle);
+ if (!entry)
+ return;
+
+ nouveau_ramht_remove_hash(chan, entry->handle);
+ nouveau_gpuobj_ref(NULL, &entry->gpuobj);
+ kfree(entry);
}
struct nouveau_gpuobj *
@@ -265,23 +286,19 @@ void
nouveau_ramht_ref(struct nouveau_ramht *ref, struct nouveau_ramht **ptr,
struct nouveau_channel *chan)
{
- struct nouveau_ramht_entry *entry, *tmp;
+ struct nouveau_ramht_entry *entry;
struct nouveau_ramht *ramht;
- unsigned long flags;
if (ref)
kref_get(&ref->refcount);
ramht = *ptr;
if (ramht) {
- spin_lock_irqsave(&ramht->lock, flags);
- list_for_each_entry_safe(entry, tmp, &ramht->entries, head) {
- if (entry->channel != chan)
- continue;
-
- nouveau_ramht_remove_locked(chan, entry->handle);
+ while ((entry = nouveau_ramht_remove_entry(chan, 0))) {
+ nouveau_ramht_remove_hash(chan, entry->handle);
+ nouveau_gpuobj_ref(NULL, &entry->gpuobj);
+ kfree(entry);
}
- spin_unlock_irqrestore(&ramht->lock, flags);
kref_put(&ramht->refcount, nouveau_ramht_del);
}