drm/vmwgfx: Remove the resource avail field

This field was previously used to prevent a lookup of a resource before its
constructor had run to its end. This was mainly intended for an interface
that is now removed that allowed looking up a resource by its device id.

Currently all affected resources are added to the lookup mechanism (its
TTM prime object is initialized) late in the constructor where it's OK to
look up the resource.

This means we can change the device resource_lock to an ordinary spinlock
instead of an rwlock and remove a locking sequence during lookup.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>

1 files changed, 23 insertions, 52 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index 315b3d60567d..55df79eccd57 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -58,11 +58,11 @@ void vmw_resource_release_id(struct vmw_resource *res)
 	struct vmw_private *dev_priv = res->dev_priv;
 	struct idr *idr = &dev_priv->res_idr[res->func->res_type];
 
-	write_lock(&dev_priv->resource_lock);
+	spin_lock(&dev_priv->resource_lock);
 	if (res->id != -1)
 		idr_remove(idr, res->id);
 	res->id = -1;
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 }
 
 static void vmw_resource_release(struct kref *kref)
@@ -73,10 +73,9 @@ static void vmw_resource_release(struct kref *kref)
 	int id;
 	struct idr *idr = &dev_priv->res_idr[res->func->res_type];
 
-	write_lock(&dev_priv->resource_lock);
-	res->avail = false;
+	spin_lock(&dev_priv->resource_lock);
 	list_del_init(&res->lru_head);
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 	if (res->backup) {
 		struct ttm_buffer_object *bo = &res->backup->base;
 
@@ -108,10 +107,10 @@ static void vmw_resource_release(struct kref *kref)
 	else
 		kfree(res);
 
-	write_lock(&dev_priv->resource_lock);
+	spin_lock(&dev_priv->resource_lock);
 	if (id != -1)
 		idr_remove(idr, id);
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 }
 
 void vmw_resource_unreference(struct vmw_resource **p_res)
@@ -140,13 +139,13 @@ int vmw_resource_alloc_id(struct vmw_resource *res)
 	BUG_ON(res->id != -1);
 
 	idr_preload(GFP_KERNEL);
-	write_lock(&dev_priv->resource_lock);
+	spin_lock(&dev_priv->resource_lock);
 
 	ret = idr_alloc(idr, res, 1, 0, GFP_NOWAIT);
 	if (ret >= 0)
 		res->id = ret;
 
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 	idr_preload_end();
 	return ret < 0 ? ret : 0;
 }
@@ -170,7 +169,6 @@ int vmw_resource_init(struct vmw_private *dev_priv, struct vmw_resource *res,
 	kref_init(&res->kref);
 	res->hw_destroy = NULL;
 	res->res_free = res_free;
-	res->avail = false;
 	res->dev_priv = dev_priv;
 	res->func = func;
 	INIT_LIST_HEAD(&res->lru_head);
@@ -187,28 +185,6 @@ int vmw_resource_init(struct vmw_private *dev_priv, struct vmw_resource *res,
 		return vmw_resource_alloc_id(res);
 }
 
-/**
- * vmw_resource_activate
- *
- * @res:        Pointer to the newly created resource
- * @hw_destroy: Destroy function. NULL if none.
- *
- * Activate a resource after the hardware has been made aware of it.
- * Set tye destroy function to @destroy. Typically this frees the
- * resource and destroys the hardware resources associated with it.
- * Activate basically means that the function vmw_resource_lookup will
- * find it.
- */
-void vmw_resource_activate(struct vmw_resource *res,
-			   void (*hw_destroy) (struct vmw_resource *))
-{
-	struct vmw_private *dev_priv = res->dev_priv;
-
-	write_lock(&dev_priv->resource_lock);
-	res->avail = true;
-	res->hw_destroy = hw_destroy;
-	write_unlock(&dev_priv->resource_lock);
-}
 
 /**
  * vmw_user_resource_lookup_handle - lookup a struct resource from a
@@ -243,15 +219,10 @@ int vmw_user_resource_lookup_handle(struct vmw_private *dev_priv,
 		goto out_bad_resource;
 
 	res = converter->base_obj_to_res(base);
-
-	read_lock(&dev_priv->resource_lock);
-	if (!res->avail || res->res_free != converter->res_free) {
-		read_unlock(&dev_priv->resource_lock);
+	if (res->res_free != converter->res_free)
 		goto out_bad_resource;
-	}
 
 	kref_get(&res->kref);
-	read_unlock(&dev_priv->resource_lock);
 
 	*p_res = res;
 	ret = 0;
@@ -422,10 +393,10 @@ void vmw_resource_unreserve(struct vmw_resource *res,
 	if (!res->func->may_evict || res->id == -1 || res->pin_count)
 		return;
 
-	write_lock(&dev_priv->resource_lock);
+	spin_lock(&dev_priv->resource_lock);
 	list_add_tail(&res->lru_head,
 		      &res->dev_priv->res_lru[res->func->res_type]);
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 }
 
 /**
@@ -504,9 +475,9 @@ int vmw_resource_reserve(struct vmw_resource *res, bool interruptible,
 	struct vmw_private *dev_priv = res->dev_priv;
 	int ret;
 
-	write_lock(&dev_priv->resource_lock);
+	spin_lock(&dev_priv->resource_lock);
 	list_del_init(&res->lru_head);
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 
 	if (res->func->needs_backup && res->backup == NULL &&
 	    !no_backup) {
@@ -619,12 +590,12 @@ int vmw_resource_validate(struct vmw_resource *res, bool intr)
 		if (likely(ret != -EBUSY))
 			break;
 
-		write_lock(&dev_priv->resource_lock);
+		spin_lock(&dev_priv->resource_lock);
 		if (list_empty(lru_list) || !res->func->may_evict) {
 			DRM_ERROR("Out of device device resources "
 				  "for %s.\n", res->func->type_name);
 			ret = -EBUSY;
-			write_unlock(&dev_priv->resource_lock);
+			spin_unlock(&dev_priv->resource_lock);
 			break;
 		}
 
@@ -633,14 +604,14 @@ int vmw_resource_validate(struct vmw_resource *res, bool intr)
 					  lru_head));
 		list_del_init(&evict_res->lru_head);
 
-		write_unlock(&dev_priv->resource_lock);
+		spin_unlock(&dev_priv->resource_lock);
 
 		/* Trylock backup buffers with a NULL ticket. */
 		ret = vmw_resource_do_evict(NULL, evict_res, intr);
 		if (unlikely(ret != 0)) {
-			write_lock(&dev_priv->resource_lock);
+			spin_lock(&dev_priv->resource_lock);
 			list_add_tail(&evict_res->lru_head, lru_list);
-			write_unlock(&dev_priv->resource_lock);
+			spin_unlock(&dev_priv->resource_lock);
 			if (ret == -ERESTARTSYS ||
 			    ++err_count > VMW_RES_EVICT_ERR_COUNT) {
 				vmw_resource_unreference(&evict_res);
@@ -822,7 +793,7 @@ static void vmw_resource_evict_type(struct vmw_private *dev_priv,
 	struct ww_acquire_ctx ticket;
 
 	do {
-		write_lock(&dev_priv->resource_lock);
+		spin_lock(&dev_priv->resource_lock);
 
 		if (list_empty(lru_list))
 			goto out_unlock;
@@ -831,14 +802,14 @@ static void vmw_resource_evict_type(struct vmw_private *dev_priv,
 			list_first_entry(lru_list, struct vmw_resource,
 					 lru_head));
 		list_del_init(&evict_res->lru_head);
-		write_unlock(&dev_priv->resource_lock);
+		spin_unlock(&dev_priv->resource_lock);
 
 		/* Wait lock backup buffers with a ticket. */
 		ret = vmw_resource_do_evict(&ticket, evict_res, false);
 		if (unlikely(ret != 0)) {
-			write_lock(&dev_priv->resource_lock);
+			spin_lock(&dev_priv->resource_lock);
 			list_add_tail(&evict_res->lru_head, lru_list);
-			write_unlock(&dev_priv->resource_lock);
+			spin_unlock(&dev_priv->resource_lock);
 			if (++err_count > VMW_RES_EVICT_ERR_COUNT) {
 				vmw_resource_unreference(&evict_res);
 				return;
@@ -849,7 +820,7 @@ static void vmw_resource_evict_type(struct vmw_private *dev_priv,
 	} while (1);
 
 out_unlock:
-	write_unlock(&dev_priv->resource_lock);
+	spin_unlock(&dev_priv->resource_lock);
 }
 
 /**