drm/gem: Drop struct_mutex requirement from drm_gem_mmap_obj

Since

commit 131e663b
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jul 9 23:32:33 2015 +0200

    drm/gem: rip out drm vma accounting for gem mmaps

there is no need for this any more.

v2: Fixup compile noise spotted by 0-day build.

Link: http://mid.gmane.org/1444894601-5200-9-git-send-email-daniel.vetter@ffwll.chReviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

drivers/gpu/drm/drm_gem.c

@@ -810,8 +810,6 @@ EXPORT_SYMBOL(drm_gem_vm_close);
  * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
  * callers must verify access restrictions before calling this helper.
  *
- * NOTE: This function has to be protected with dev->struct_mutex
- *
  * Return 0 or success or -EINVAL if the object size is smaller than the VMA
  * size, or if no gem_vm_ops are provided.
  */
@@ -820,8 +818,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
 {
 	struct drm_device *dev = obj->dev;
 
-	lockdep_assert_held(&dev->struct_mutex);
-
 	/* Check for valid size. */
 	if (obj_size < vma->vm_end - vma->vm_start)
 		return -EINVAL;

drivers/gpu/drm/drm_gem_cma_helper.c

@@ -484,9 +484,7 @@ int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
 	struct drm_device *dev = obj->dev;
 	int ret;
 
-	mutex_lock(&dev->struct_mutex);
 	ret = drm_gem_mmap_obj(obj, obj->size, vma);
-	mutex_unlock(&dev->struct_mutex);
 	if (ret < 0)
 		return ret;
 

drivers/gpu/drm/msm/msm_fbdev.c

@@ -68,12 +68,7 @@ static int msm_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	if (drm_device_is_unplugged(dev))
 		return -ENODEV;
 
-	mutex_lock(&dev->struct_mutex);
-
 	ret = drm_gem_mmap_obj(drm_obj, drm_obj->size, vma);
-
-	mutex_unlock(&dev->struct_mutex);
-
 	if (ret) {
 		pr_err("%s:drm_gem_mmap_obj fail\n", __func__);
 		return ret;

drivers/gpu/drm/msm/msm_gem_prime.c

@@ -45,9 +45,7 @@ int msm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 {
 	int ret;
 
-	mutex_lock(&obj->dev->struct_mutex);
 	ret = drm_gem_mmap_obj(obj, obj->size, vma);
-	mutex_unlock(&obj->dev->struct_mutex);
 	if (ret < 0)
 		return ret;
 

drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c

@@ -140,15 +140,12 @@ static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 		struct vm_area_struct *vma)
 {
 	struct drm_gem_object *obj = buffer->priv;
-	struct drm_device *dev = obj->dev;
 	int ret = 0;
 
 	if (WARN_ON(!obj->filp))
 		return -EINVAL;
 
-	mutex_lock(&dev->struct_mutex);
 	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
-	mutex_unlock(&dev->struct_mutex);
 	if (ret < 0)
 		return ret;
 

drivers/gpu/drm/rockchip/rockchip_drm_gem.c

@@ -79,12 +79,9 @@ static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
 int rockchip_gem_mmap_buf(struct drm_gem_object *obj,
 			  struct vm_area_struct *vma)
 {
-	struct drm_device *drm = obj->dev;
 	int ret;
 
-	mutex_lock(&drm->struct_mutex);
 	ret = drm_gem_mmap_obj(obj, obj->size, vma);
-	mutex_unlock(&drm->struct_mutex);
 	if (ret)
 		return ret;