[PATCH v3 2/3] drm: Add a drm_gem_objects_lookup helper

From: Rob Herring
Date: Tue Apr 09 2019 - 16:54:47 EST


Similar to the single handle drm_gem_object_lookup(),
drm_gem_objects_lookup() takes an array of handles and returns an array
of GEM objects.

v2:
- Take the userspace pointer directly and allocate the array.
- Expand the function documentation.

Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
Cc: Sean Paul <sean@xxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Acked-by: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
drivers/gpu/drm/drm_gem.c | 93 ++++++++++++++++++++++++++++++++++-----
include/drm/drm_gem.h | 2 +
2 files changed, 85 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 388b3742e562..faa2718e85e8 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -663,6 +663,85 @@ void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
}
EXPORT_SYMBOL(drm_gem_put_pages);

+static int objects_lookup(struct drm_file *filp, u32 *handle, int count,
+ struct drm_gem_object **objs)
+{
+ int i, ret = 0;
+ struct drm_gem_object *obj;
+
+ spin_lock(&filp->table_lock);
+
+ for (i = 0; i < count; i++) {
+ /* Check if we currently have a reference on the object */
+ obj = idr_find(&filp->object_idr, handle[i]);
+ if (!obj) {
+ ret = -ENOENT;
+ break;
+ }
+ drm_gem_object_get(obj);
+ objs[i] = obj;
+ }
+ spin_unlock(&filp->table_lock);
+
+ return ret;
+}
+
+/**
+ * drm_gem_objects_lookup - look up GEM objects from an array of handles
+ * @filp: DRM file private date
+ * @bo_handles: user pointer to array of userspace handle
+ * @count: size of handle array
+ * @objs_out: returned pointer to array of drm_gem_object pointers
+ *
+ * Takes an array of userspace handles and returns a newly allocated array of
+ * GEM objects.
+ *
+ * For a single handle lookup, use drm_gem_object_lookup().
+ *
+ * Returns:
+ *
+ * @objs filled in with GEM object pointers. Returned GEM objects need to be
+ * released with drm_gem_object_put(). -ENOENT is returned on a lookup
+ * failure. 0 is returned on success.
+ *
+ */
+int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
+ int count, struct drm_gem_object ***objs_out)
+{
+ int ret;
+ u32 *handles;
+ struct drm_gem_object **objs;
+
+ if (!count)
+ return 0;
+
+ objs = kvmalloc_array(count, sizeof(struct drm_gem_object *),
+ GFP_KERNEL | __GFP_ZERO);
+ if (!objs)
+ return -ENOMEM;
+
+ handles = kvmalloc_array(count, sizeof(u32), GFP_KERNEL);
+ if (!handles) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (copy_from_user(handles, bo_handles, count * sizeof(u32))) {
+ ret = -EFAULT;
+ DRM_DEBUG("Failed to copy in GEM handles\n");
+ goto out;
+ }
+
+ ret = objects_lookup(filp, handles, count, objs);
+ *objs_out = objs;
+
+out:
+ kvfree(handles);
+ return ret;
+
+}
+EXPORT_SYMBOL(drm_gem_objects_lookup);
+
/**
* drm_gem_object_lookup - look up a GEM object from its handle
* @filp: DRM file private date
@@ -672,21 +751,15 @@ EXPORT_SYMBOL(drm_gem_put_pages);
*
* A reference to the object named by the handle if such exists on @filp, NULL
* otherwise.
+ *
+ * If looking up an array of handles, use drm_gem_objects_lookup().
*/
struct drm_gem_object *
drm_gem_object_lookup(struct drm_file *filp, u32 handle)
{
- struct drm_gem_object *obj;
-
- spin_lock(&filp->table_lock);
-
- /* Check if we currently have a reference on the object */
- obj = idr_find(&filp->object_idr, handle);
- if (obj)
- drm_gem_object_get(obj);
-
- spin_unlock(&filp->table_lock);
+ struct drm_gem_object *obj = NULL;

+ objects_lookup(filp, &handle, 1, &obj);
return obj;
}
EXPORT_SYMBOL(drm_gem_object_lookup);
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 2955aaab3dca..5ee85c9eaa9d 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -381,6 +381,8 @@ struct page **drm_gem_get_pages(struct drm_gem_object *obj);
void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
bool dirty, bool accessed);

+int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
+ int count, struct drm_gem_object ***objs_out);
struct drm_gem_object *drm_gem_object_lookup(struct drm_file *filp, u32 handle);
long drm_gem_reservation_object_wait(struct drm_file *filep, u32 handle,
bool wait_all, unsigned long timeout);
--
2.19.1