drm/vmwgfx: Remove the reservation semaphore

Now since Christian reworked TTM to always keep objects on the LRU
list unless they are pinned we shouldn't need the reservation
semaphore. It makes the driver code a lot cleaner, especially
because it was a little hard to reason when and where the
reservation semaphore needed to be held.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210505035740.286923-5-zackr@vmware.com

1 files changed, 1 insertions, 13 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 1b27d7f7fcfa..22a2874116c9 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -708,7 +708,6 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 
 	mutex_init(&dev_priv->cmdbuf_mutex);
 	mutex_init(&dev_priv->binding_mutex);
-	ttm_lock_init(&dev_priv->reservation_sem);
 	spin_lock_init(&dev_priv->resource_lock);
 	spin_lock_init(&dev_priv->hw_lock);
 	spin_lock_init(&dev_priv->waiter_lock);
@@ -966,6 +965,7 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 		DRM_INFO("SM4_1 support available.\n");
 	if (dev_priv->sm_type == VMW_SM_4)
 		DRM_INFO("SM4 support available.\n");
+	DRM_INFO("Running without reservation semaphore\n");
 
 	snprintf(host_log, sizeof(host_log), "vmwgfx: Module Version: %d.%d.%d",
 		VMWGFX_DRIVER_MAJOR, VMWGFX_DRIVER_MINOR,
@@ -1191,9 +1191,7 @@ static void __vmw_svga_enable(struct vmw_private *dev_priv)
  */
 void vmw_svga_enable(struct vmw_private *dev_priv)
 {
-	(void) ttm_read_lock(&dev_priv->reservation_sem, false);
 	__vmw_svga_enable(dev_priv);
-	ttm_read_unlock(&dev_priv->reservation_sem);
 }
 
 /**
@@ -1238,7 +1236,6 @@ void vmw_svga_disable(struct vmw_private *dev_priv)
 	 *
 	 */
 	vmw_kms_lost_device(&dev_priv->drm);
-	ttm_write_lock(&dev_priv->reservation_sem, false);
 	if (ttm_resource_manager_used(man)) {
 		if (ttm_resource_manager_evict_all(&dev_priv->bdev, man))
 			DRM_ERROR("Failed evicting VRAM buffers.\n");
@@ -1247,7 +1244,6 @@ void vmw_svga_disable(struct vmw_private *dev_priv)
 			  SVGA_REG_ENABLE_HIDE |
 			  SVGA_REG_ENABLE_ENABLE);
 	}
-	ttm_write_unlock(&dev_priv->reservation_sem);
 }
 
 static void vmw_remove(struct pci_dev *pdev)
@@ -1287,14 +1283,12 @@ static int vmwgfx_pm_notifier(struct notifier_block *nb, unsigned long val,
 		 * Once user-space processes have been frozen, we can release
 		 * the lock again.
 		 */
-		ttm_suspend_lock(&dev_priv->reservation_sem);
 		dev_priv->suspend_locked = true;
 		break;
 	case PM_POST_HIBERNATION:
 	case PM_POST_RESTORE:
 		if (READ_ONCE(dev_priv->suspend_locked)) {
 			dev_priv->suspend_locked = false;
-			ttm_suspend_unlock(&dev_priv->reservation_sem);
 		}
 		break;
 	default:
@@ -1353,20 +1347,16 @@ static int vmw_pm_freeze(struct device *kdev)
 	int ret;
 
 	/*
-	 * Unlock for vmw_kms_suspend.
 	 * No user-space processes should be running now.
 	 */
-	ttm_suspend_unlock(&dev_priv->reservation_sem);
 	ret = vmw_kms_suspend(&dev_priv->drm);
 	if (ret) {
-		ttm_suspend_lock(&dev_priv->reservation_sem);
 		DRM_ERROR("Failed to freeze modesetting.\n");
 		return ret;
 	}
 	if (dev_priv->enable_fb)
 		vmw_fb_off(dev_priv);
 
-	ttm_suspend_lock(&dev_priv->reservation_sem);
 	vmw_execbuf_release_pinned_bo(dev_priv);
 	vmw_resource_evict_all(dev_priv);
 	vmw_release_device_early(dev_priv);
@@ -1379,7 +1369,6 @@ static int vmw_pm_freeze(struct device *kdev)
 			vmw_fifo_resource_inc(dev_priv);
 		WARN_ON(vmw_request_device_late(dev_priv));
 		dev_priv->suspend_locked = false;
-		ttm_suspend_unlock(&dev_priv->reservation_sem);
 		if (dev_priv->suspend_state)
 			vmw_kms_resume(dev);
 		if (dev_priv->enable_fb)
@@ -1416,7 +1405,6 @@ static int vmw_pm_restore(struct device *kdev)
 
 	vmw_fence_fifo_up(dev_priv->fman);
 	dev_priv->suspend_locked = false;
-	ttm_suspend_unlock(&dev_priv->reservation_sem);
 	if (dev_priv->suspend_state)
 		vmw_kms_resume(&dev_priv->drm);