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>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 33176d05db3542903f1c919b59f68cad2da22044..1e114893a0016c8afd0c51eed7ff5d4a0936640c 100644 (file)
--- 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 8725b79e7847d68239a25413c482883e44024704..07cda8cbbddbcb5e6f56127c57dac0e683541fb9 100644 (file)
--- 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;
 }