drm/vmwgfx: Introduce a pin count to allow for recursive pinning v2

v2: Fix dma buffer validation on resource pinning.

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

1 files changed, 80 insertions, 102 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c
index 914b375763dc..4b9344dd6c27 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c
@@ -32,25 +32,20 @@
 
 
 /**
- * vmw_dmabuf_to_placement - Validate a buffer to placement.
+ * vmw_dmabuf_pin_in_placement - Validate a buffer to placement.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to move.
- * @pin:  Pin buffer if true.
+ * @placement:  The placement to pin it.
  * @interruptible:  Use interruptible wait.
  *
- * May only be called by the current master since it assumes that the
- * master lock is the current master's lock.
- * This function takes the master's lock in write mode.
- * Flushes and unpins the query bo to avoid failures.
- *
  * Returns
  *  -ERESTARTSYS if interrupted by a signal.
  */
-int vmw_dmabuf_to_placement(struct vmw_private *dev_priv,
-			    struct vmw_dma_buffer *buf,
-			    struct ttm_placement *placement,
-			    bool interruptible)
+int vmw_dmabuf_pin_in_placement(struct vmw_private *dev_priv,
+				struct vmw_dma_buffer *buf,
+				struct ttm_placement *placement,
+				bool interruptible)
 {
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;
@@ -66,6 +61,8 @@ int vmw_dmabuf_to_placement(struct vmw_private *dev_priv,
 		goto err;
 
 	ret = ttm_bo_validate(bo, placement, interruptible, false);
+	if (!ret)
+		vmw_bo_pin_reserved(buf, true);
 
 	ttm_bo_unreserve(bo);
 
@@ -75,12 +72,10 @@ err:
 }
 
 /**
- * vmw_dmabuf_to_vram_or_gmr - Move a buffer to vram or gmr.
+ * vmw_dmabuf_pin_in_vram_or_gmr - Move a buffer to vram or gmr.
  *
- * May only be called by the current master since it assumes that the
- * master lock is the current master's lock.
- * This function takes the master's lock in write mode.
- * Flushes and unpins the query bo if @pin == true to avoid failures.
+ * This function takes the reservation_sem in write mode.
+ * Flushes and unpins the query bo to avoid failures.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to move.
@@ -90,55 +85,34 @@ err:
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
-int vmw_dmabuf_to_vram_or_gmr(struct vmw_private *dev_priv,
-			      struct vmw_dma_buffer *buf,
-			      bool pin, bool interruptible)
+int vmw_dmabuf_pin_in_vram_or_gmr(struct vmw_private *dev_priv,
+				  struct vmw_dma_buffer *buf,
+				  bool interruptible)
 {
 	struct ttm_buffer_object *bo = &buf->base;
-	struct ttm_placement *placement;
 	int ret;
 
 	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
 		return ret;
 
-	if (pin)
-		vmw_execbuf_release_pinned_bo(dev_priv);
+	vmw_execbuf_release_pinned_bo(dev_priv);
 
 	ret = ttm_bo_reserve(bo, interruptible, false, false, NULL);
 	if (unlikely(ret != 0))
 		goto err;
 
-	/**
-	 * Put BO in VRAM if there is space, otherwise as a GMR.
-	 * If there is no space in VRAM and GMR ids are all used up,
-	 * start evicting GMRs to make room. If the DMA buffer can't be
-	 * used as a GMR, this will return -ENOMEM.
-	 */
-
-	if (pin)
-		placement = &vmw_vram_gmr_ne_placement;
-	else
-		placement = &vmw_vram_gmr_placement;
-
-	ret = ttm_bo_validate(bo, placement, interruptible, false);
+	ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, interruptible,
+			      false);
 	if (likely(ret == 0) || ret == -ERESTARTSYS)
-		goto err_unreserve;
-
+		goto out_unreserve;
 
-	/**
-	 * If that failed, try VRAM again, this time evicting
-	 * previous contents.
-	 */
-
-	if (pin)
-		placement = &vmw_vram_ne_placement;
-	else
-		placement = &vmw_vram_placement;
+	ret = ttm_bo_validate(bo, &vmw_vram_placement, interruptible, false);
 
-	ret = ttm_bo_validate(bo, placement, interruptible, false);
+out_unreserve:
+	if (!ret)
+		vmw_bo_pin_reserved(buf, true);
 
-err_unreserve:
 	ttm_bo_unreserve(bo);
 err:
 	ttm_write_unlock(&dev_priv->reservation_sem);
@@ -146,67 +120,50 @@ err:
 }
 
 /**
- * vmw_dmabuf_to_vram - Move a buffer to vram.
+ * vmw_dmabuf_pin_in_vram - Move a buffer to vram.
  *
- * May only be called by the current master since it assumes that the
- * master lock is the current master's lock.
- * This function takes the master's lock in write mode.
+ * This function takes the reservation_sem in write mode.
+ * Flushes and unpins the query bo to avoid failures.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to move.
- * @pin:  Pin buffer in vram if true.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
-int vmw_dmabuf_to_vram(struct vmw_private *dev_priv,
-		       struct vmw_dma_buffer *buf,
-		       bool pin, bool interruptible)
+int vmw_dmabuf_pin_in_vram(struct vmw_private *dev_priv,
+			   struct vmw_dma_buffer *buf,
+			   bool interruptible)
 {
-	struct ttm_placement *placement;
-
-	if (pin)
-		placement = &vmw_vram_ne_placement;
-	else
-		placement = &vmw_vram_placement;
-
-	return vmw_dmabuf_to_placement(dev_priv, buf,
-				       placement,
-				       interruptible);
+	return vmw_dmabuf_pin_in_placement(dev_priv, buf, &vmw_vram_placement,
+					   interruptible);
 }
 
 /**
- * vmw_dmabuf_to_start_of_vram - Move a buffer to start of vram.
+ * vmw_dmabuf_pin_in_start_of_vram - Move a buffer to start of vram.
  *
- * May only be called by the current master since it assumes that the
- * master lock is the current master's lock.
- * This function takes the master's lock in write mode.
- * Flushes and unpins the query bo if @pin == true to avoid failures.
+ * This function takes the reservation_sem in write mode.
+ * Flushes and unpins the query bo to avoid failures.
  *
  * @dev_priv:  Driver private.
- * @buf:  DMA buffer to move.
- * @pin:  Pin buffer in vram if true.
+ * @buf:  DMA buffer to pin.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
-int vmw_dmabuf_to_start_of_vram(struct vmw_private *dev_priv,
-				struct vmw_dma_buffer *buf,
-				bool pin, bool interruptible)
+int vmw_dmabuf_pin_in_start_of_vram(struct vmw_private *dev_priv,
+				    struct vmw_dma_buffer *buf,
+				    bool interruptible)
 {
 	struct ttm_buffer_object *bo = &buf->base;
 	struct ttm_placement placement;
 	struct ttm_place place;
 	int ret = 0;
 
-	if (pin)
-		place = vmw_vram_ne_placement.placement[0];
-	else
-		place = vmw_vram_placement.placement[0];
+	place = vmw_vram_placement.placement[0];
 	place.lpfn = bo->num_pages;
-
 	placement.num_placement = 1;
 	placement.placement = &place;
 	placement.num_busy_placement = 1;
@@ -216,13 +173,16 @@ int vmw_dmabuf_to_start_of_vram(struct vmw_private *dev_priv,
 	if (unlikely(ret != 0))
 		return ret;
 
-	if (pin)
-		vmw_execbuf_release_pinned_bo(dev_priv);
+	vmw_execbuf_release_pinned_bo(dev_priv);
 	ret = ttm_bo_reserve(bo, interruptible, false, false, NULL);
 	if (unlikely(ret != 0))
 		goto err_unlock;
 
-	/* Is this buffer already in vram but not at the start of it? */
+	/*
+	 * Is this buffer already in vram but not at the start of it?
+	 * In that case, evict it first because TTM isn't good at handling
+	 * that situation.
+	 */
 	if (bo->mem.mem_type == TTM_PL_VRAM &&
 	    bo->mem.start < bo->num_pages &&
 	    bo->mem.start > 0)
@@ -230,8 +190,10 @@ int vmw_dmabuf_to_start_of_vram(struct vmw_private *dev_priv,
 
 	ret = ttm_bo_validate(bo, &placement, interruptible, false);
 
-	/* For some reason we didn't up at the start of vram */
+	/* For some reason we didn't end up at the start of vram */
 	WARN_ON(ret == 0 && bo->offset != 0);
+	if (!ret)
+		vmw_bo_pin_reserved(buf, true);
 
 	ttm_bo_unreserve(bo);
 err_unlock:
@@ -240,13 +202,10 @@ err_unlock:
 	return ret;
 }
 
-
 /**
- * vmw_dmabuf_upin - Unpin the buffer given buffer, does not move the buffer.
+ * vmw_dmabuf_unpin - Unpin the buffer given buffer, does not move the buffer.
  *
- * May only be called by the current master since it assumes that the
- * master lock is the current master's lock.
- * This function takes the master's lock in write mode.
+ * This function takes the reservation_sem in write mode.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to unpin.
@@ -259,16 +218,25 @@ int vmw_dmabuf_unpin(struct vmw_private *dev_priv,
 		     struct vmw_dma_buffer *buf,
 		     bool interruptible)
 {
-	/*
-	 * We could in theory early out if the buffer is
-	 * unpinned but we need to lock and reserve the buffer
-	 * anyways so we don't gain much by that.
-	 */
-	return vmw_dmabuf_to_placement(dev_priv, buf,
-				       &vmw_evictable_placement,
-				       interruptible);
-}
+	struct ttm_buffer_object *bo = &buf->base;
+	int ret;
 
+	ret = ttm_read_lock(&dev_priv->reservation_sem, interruptible);
+	if (unlikely(ret != 0))
+		return ret;
+
+	ret = ttm_bo_reserve(bo, interruptible, false, false, 0);
+	if (unlikely(ret != 0))
+		goto err;
+
+	vmw_bo_pin_reserved(buf, false);
+
+	ttm_bo_unreserve(bo);
+
+err:
+	ttm_read_unlock(&dev_priv->reservation_sem);
+	return ret;
+}
 
 /**
  * vmw_bo_get_guest_ptr - Get the guest ptr representing the current placement
@@ -291,21 +259,31 @@ void vmw_bo_get_guest_ptr(const struct ttm_buffer_object *bo,
 
 
 /**
- * vmw_bo_pin - Pin or unpin a buffer object without moving it.
+ * vmw_bo_pin_reserved - Pin or unpin a buffer object without moving it.
  *
- * @bo: The buffer object. Must be reserved.
+ * @vbo: The buffer object. Must be reserved.
  * @pin: Whether to pin or unpin.
  *
  */
-void vmw_bo_pin(struct ttm_buffer_object *bo, bool pin)
+void vmw_bo_pin_reserved(struct vmw_dma_buffer *vbo, bool pin)
 {
 	struct ttm_place pl;
 	struct ttm_placement placement;
+	struct ttm_buffer_object *bo = &vbo->base;
 	uint32_t old_mem_type = bo->mem.mem_type;
 	int ret;
 
 	lockdep_assert_held(&bo->resv->lock.base);
 
+	if (pin) {
+		if (vbo->pin_count++ > 0)
+			return;
+	} else {
+		WARN_ON(vbo->pin_count <= 0);
+		if (--vbo->pin_count > 0)
+			return;
+	}
+
 	pl.fpfn = 0;
 	pl.lpfn = 0;
 	pl.flags = TTM_PL_FLAG_VRAM | VMW_PL_FLAG_GMR | VMW_PL_FLAG_MOB