drm/vmwgfx: Fix a couple of lock dependency violations

Experimental lockdep annotation added to the TTM lock has unveiled a
couple of lock dependency violations in the vmwgfx driver. In both
cases it turns out that the device_private::reservation_sem is not
needed so the offending code is moved out of that lock.

Cc: <stable@vger.kernel.org>
Acked-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

2 files changed, 6 insertions, 16 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 33176d05db35..1e114893a001 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -2780,13 +2780,11 @@ int vmw_execbuf_ioctl(struct drm_device *dev, void *data,
                                   NULL, arg->command_size, arg->throttle_us,
                                   (void __user *)(unsigned long)arg->fence_rep,
                                   NULL);
-
+        ttm_read_unlock(&dev_priv->reservation_sem);
         if (unlikely(ret != 0))
-                goto out_unlock;
+                return ret;
 
         vmw_kms_cursor_post_execbuf(dev_priv);
 
-out_unlock:
-        ttm_read_unlock(&dev_priv->reservation_sem);
-        return ret;
+        return 0;
 }
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 8725b79e7847..07cda8cbbddb 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -2033,23 +2033,17 @@ int vmw_kms_update_layout_ioctl(struct drm_device *dev, void *data,
         int i;
         struct drm_mode_config *mode_config = &dev->mode_config;
 
-        ret = ttm_read_lock(&dev_priv->reservation_sem, true);
-        if (unlikely(ret != 0))
-                return ret;
-
         if (!arg->num_outputs) {
                 struct drm_vmw_rect def_rect = {0, 0, 800, 600};
                 vmw_du_update_layout(dev_priv, 1, &def_rect);
-                goto out_unlock;
+                return 0;
         }
 
         rects_size = arg->num_outputs * sizeof(struct drm_vmw_rect);
         rects = kcalloc(arg->num_outputs, sizeof(struct drm_vmw_rect),
                         GFP_KERNEL);
-        if (unlikely(!rects)) {
-                ret = -ENOMEM;
-                goto out_unlock;
-        }
+        if (unlikely(!rects))
+                return -ENOMEM;
 
         user_rects = (void __user *)(unsigned long)arg->rects;
         ret = copy_from_user(rects, user_rects, rects_size);
@@ -2074,7 +2068,5 @@ int vmw_kms_update_layout_ioctl(struct drm_device *dev, void *data,
 
 out_free:
         kfree(rects);
-out_unlock:
-        ttm_read_unlock(&dev_priv->reservation_sem);
         return ret;
 }