[PATCH v3 2/8] drm/gem: Create a drm_gem_object_init_with_mnt() function

[Maíra Canal <mcanal@xxxxxxxxxx>]

For some applications, such as applications that uses huge pages, we might
want to have a different mountpoint, for which we pass mount flags that
better match our usecase.

Therefore, create a new function `drm_gem_object_init_with_mnt()` that
allow us to define the tmpfs mountpoint where the GEM object will be
created. If this parameter is NULL, then we fallback to `shmem_file_setup()`.

Signed-off-by: Maíra Canal <mcanal@xxxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
---
 drivers/gpu/drm/drm_gem.c | 34 ++++++++++++++++++++++++++++++----
 include/drm/drm_gem.h     |  3 +++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index d4bbc5d109c8..74ebe68e3d61 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -114,22 +114,32 @@ drm_gem_init(struct drm_device *dev)
 }
 
 /**
- * drm_gem_object_init - initialize an allocated shmem-backed GEM object
+ * drm_gem_object_init_with_mnt - initialize an allocated shmem-backed GEM
+ * object in a given shmfs mountpoint
+ *
  * @dev: drm_device the object should be initialized for
  * @obj: drm_gem_object to initialize
  * @size: object size
+ * @gemfs: tmpfs mount where the GEM object will be created. If NULL, use
+ * the usual tmpfs mountpoint (`shm_mnt`).
  *
  * Initialize an already allocated GEM object of the specified size with
  * shmfs backing store.
  */
-int drm_gem_object_init(struct drm_device *dev,
-			struct drm_gem_object *obj, size_t size)
+int drm_gem_object_init_with_mnt(struct drm_device *dev,
+				 struct drm_gem_object *obj, size_t size,
+				 struct vfsmount *gemfs)
 {
 	struct file *filp;
 
 	drm_gem_private_object_init(dev, obj, size);
 
-	filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
+	if (gemfs)
+		filp = shmem_file_setup_with_mnt(gemfs, "drm mm object", size,
+						 VM_NORESERVE);
+	else
+		filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
+
 	if (IS_ERR(filp))
 		return PTR_ERR(filp);
 
@@ -137,6 +147,22 @@ int drm_gem_object_init(struct drm_device *dev,
 
 	return 0;
 }
+EXPORT_SYMBOL(drm_gem_object_init_with_mnt);
+
+/**
+ * drm_gem_object_init - initialize an allocated shmem-backed GEM object
+ * @dev: drm_device the object should be initialized for
+ * @obj: drm_gem_object to initialize
+ * @size: object size
+ *
+ * Initialize an already allocated GEM object of the specified size with
+ * shmfs backing store.
+ */
+int drm_gem_object_init(struct drm_device *dev, struct drm_gem_object *obj,
+			size_t size)
+{
+	return drm_gem_object_init_with_mnt(dev, obj, size, NULL);
+}
 EXPORT_SYMBOL(drm_gem_object_init);
 
 /**
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index bae4865b2101..2ebf6e10cc44 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -472,6 +472,9 @@ void drm_gem_object_release(struct drm_gem_object *obj);
 void drm_gem_object_free(struct kref *kref);
 int drm_gem_object_init(struct drm_device *dev,
 			struct drm_gem_object *obj, size_t size);
+int drm_gem_object_init_with_mnt(struct drm_device *dev,
+				 struct drm_gem_object *obj, size_t size,
+				 struct vfsmount *gemfs);
 void drm_gem_private_object_init(struct drm_device *dev,
 				 struct drm_gem_object *obj, size_t size);
 void drm_gem_private_object_fini(struct drm_gem_object *obj);
-- 
2.44.0