drm/nouveau: add spinlock around ramht modifications

Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

2 files changed, 58 insertions, 21 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_ramht.c b/drivers/gpu/drm/nouveau/nouveau_ramht.c
index ccbc8d69ea68..de34b6bb059f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ramht.c
+++ b/drivers/gpu/drm/nouveau/nouveau_ramht.c
@@ -27,13 +27,13 @@
 #include "nouveau_drv.h"
 #include "nouveau_ramht.h"
 
-static uint32_t
-nouveau_ramht_hash_handle(struct nouveau_channel *chan, uint32_t handle)
+static u32
+nouveau_ramht_hash_handle(struct nouveau_channel *chan, u32 handle)
 {
         struct drm_device *dev = chan->dev;
         struct drm_nouveau_private *dev_priv = dev->dev_private;
         struct nouveau_ramht *ramht = chan->ramht;
-        uint32_t hash = 0;
+        u32 hash = 0;
         int i;
 
         NV_DEBUG(dev, "ch%d handle=0x%08x\n", chan->id, handle);
@@ -53,10 +53,10 @@ nouveau_ramht_hash_handle(struct nouveau_channel *chan, uint32_t handle)
 
 static int
 nouveau_ramht_entry_valid(struct drm_device *dev, struct nouveau_gpuobj *ramht,
-                          uint32_t offset)
+                          u32 offset)
 {
         struct drm_nouveau_private *dev_priv = dev->dev_private;
-        uint32_t ctx = nv_ro32(ramht, offset + 4);
+        u32 ctx = nv_ro32(ramht, offset + 4);
 
         if (dev_priv->card_type < NV_40)
                 return ((ctx & NV_RAMHT_CONTEXT_VALID) != 0);
@@ -72,7 +72,8 @@ nouveau_ramht_insert(struct nouveau_channel *chan, u32 handle,
         struct nouveau_instmem_engine *instmem = &dev_priv->engine.instmem;
         struct nouveau_ramht_entry *entry;
         struct nouveau_gpuobj *ramht = chan->ramht->gpuobj;
-        uint32_t ctx, co, ho;
+        unsigned long flags;
+        u32 ctx, co, ho;
 
         if (nouveau_ramht_find(chan, handle))
                 return -EEXIST;
@@ -83,7 +84,6 @@ nouveau_ramht_insert(struct nouveau_channel *chan, u32 handle,
         entry->channel = chan;
         entry->gpuobj = NULL;
         entry->handle = handle;
-        list_add(&entry->head, &chan->ramht->entries);
         nouveau_gpuobj_ref(gpuobj, &entry->gpuobj);
 
         if (dev_priv->card_type < NV_40) {
@@ -105,6 +105,9 @@ nouveau_ramht_insert(struct nouveau_channel *chan, u32 handle,
                 }
         }
 
+        spin_lock_irqsave(&chan->ramht->lock, flags);
+        list_add(&entry->head, &chan->ramht->entries);
+
         co = ho = nouveau_ramht_hash_handle(chan, handle);
         do {
                 if (!nouveau_ramht_entry_valid(dev, ramht, co)) {
@@ -114,6 +117,7 @@ nouveau_ramht_insert(struct nouveau_channel *chan, u32 handle,
                         nv_wo32(ramht, co + 0, handle);
                         nv_wo32(ramht, co + 4, ctx);
 
+                        spin_unlock_irqrestore(&chan->ramht->lock, flags);
                         instmem->flush(dev);
                         return 0;
                 }
@@ -127,12 +131,13 @@ nouveau_ramht_insert(struct nouveau_channel *chan, u32 handle,
 
         NV_ERROR(dev, "RAMHT space exhausted. ch=%d\n", chan->id);
         list_del(&entry->head);
+        spin_unlock_irqrestore(&chan->ramht->lock, flags);
         kfree(entry);
         return -ENOMEM;
 }
 
-void
-nouveau_ramht_remove(struct nouveau_channel *chan, u32 handle)
+static void
+nouveau_ramht_remove_locked(struct nouveau_channel *chan, u32 handle)
 {
         struct drm_device *dev = chan->dev;
         struct drm_nouveau_private *dev_priv = dev->dev_private;
@@ -173,17 +178,35 @@ nouveau_ramht_remove(struct nouveau_channel *chan, u32 handle)
                  chan->id, handle);
 }
 
+void
+nouveau_ramht_remove(struct nouveau_channel *chan, u32 handle)
+{
+        struct nouveau_ramht *ramht = chan->ramht;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ramht->lock, flags);
+        nouveau_ramht_remove_locked(chan, handle);
+        spin_unlock_irqrestore(&ramht->lock, flags);
+}
+
 struct nouveau_gpuobj *
 nouveau_ramht_find(struct nouveau_channel *chan, u32 handle)
 {
+        struct nouveau_ramht *ramht = chan->ramht;
         struct nouveau_ramht_entry *entry;
+        struct nouveau_gpuobj *gpuobj = NULL;
+        unsigned long flags;
 
+        spin_lock_irqsave(&ramht->lock, flags);
         list_for_each_entry(entry, &chan->ramht->entries, head) {
-                if (entry->channel == chan && entry->handle == handle)
-                        return entry->gpuobj;
+                if (entry->channel == chan && entry->handle == handle) {
+                        gpuobj = entry->gpuobj;
+                        break;
+                }
         }
+        spin_unlock_irqrestore(&ramht->lock, flags);
 
-        return NULL;
+        return gpuobj;
 }
 
 int
@@ -197,36 +220,49 @@ nouveau_ramht_new(struct drm_device *dev, struct nouveau_gpuobj *gpuobj,
                 return -ENOMEM;
 
         ramht->dev = dev;
-        ramht->refcount = 1;
+        kref_init(&ramht->refcount);
         ramht->bits = drm_order(gpuobj->size / 8);
         INIT_LIST_HEAD(&ramht->entries);
+        spin_lock_init(&ramht->lock);
         nouveau_gpuobj_ref(gpuobj, &ramht->gpuobj);
 
         *pramht = ramht;
         return 0;
 }
 
+static void
+nouveau_ramht_del(struct kref *ref)
+{
+        struct nouveau_ramht *ramht =
+                container_of(ref, struct nouveau_ramht, refcount);
+
+        nouveau_gpuobj_ref(NULL, &ramht->gpuobj);
+        kfree(ramht);
+}
+
 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 *ramht;
+        unsigned long flags;
 
         if (ref)
-                ref->refcount++;
+                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)
-                                nouveau_ramht_remove(chan, entry->handle);
-                }
+                        if (entry->channel != chan)
+                                continue;
 
-                if (--ramht->refcount == 0) {
-                        nouveau_gpuobj_ref(NULL, &ramht->gpuobj);
-                        kfree(ramht);
+                        nouveau_ramht_remove_locked(chan, entry->handle);
                 }
+                spin_unlock_irqrestore(&ramht->lock, flags);
+
+                kref_put(&ramht->refcount, nouveau_ramht_del);
         }
         *ptr = ref;
 }
diff --git a/drivers/gpu/drm/nouveau/nouveau_ramht.h b/drivers/gpu/drm/nouveau/nouveau_ramht.h
index f37737a93642..b79cb5e1a8f1 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ramht.h
+++ b/drivers/gpu/drm/nouveau/nouveau_ramht.h
@@ -34,7 +34,8 @@ struct nouveau_ramht_entry {
 
 struct nouveau_ramht {
         struct drm_device *dev;
-        int refcount;
+        struct kref refcount;
+        spinlock_t lock;
         struct nouveau_gpuobj *gpuobj;
         struct list_head entries;
         int bits;