[PATCH v2 1/6] drm/gem: refine drm_gem_objects_lookup

[Qiang Yu]

drm_gem_objects_lookup does not use user space bo handles
directly and left the user to kernel copy work to a new
interface drm_gem_objects_lookup_user.

This is for driver like lima which does not pass gem bo
handles continously in an array in ioctl argument.

v2:
1. add drm_gem_objects_lookup_user
2. remove none-zero check as all caller will check before
   calling this function

Cc: Rob Herring <robh at kernel.org>
Cc: Tomeu Vizoso <tomeu.vizoso at collabora.com>
Cc: Steven Price <steven.price at arm.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Suggested-by: Rob Herring <robh at kernel.org>
Signed-off-by: Qiang Yu <yuq825 at gmail.com>
---
 drivers/gpu/drm/drm_gem.c               | 57 +++++++++++++++++++------
 drivers/gpu/drm/panfrost/panfrost_drv.c |  6 +--
 include/drm/drm_gem.h                   |  4 +-
 3 files changed, 49 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 6854f5867d51..a5e88c3e6d25 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -679,11 +679,11 @@ static int objects_lookup(struct drm_file *filp, u32 *handle, int count,
 /**
  * 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
+ * @bo_handles: array of GEM object handles
  * @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
+ * Takes an array of GEM object handles and returns a newly allocated array of
  * GEM objects.
  *
  * For a single handle lookup, use drm_gem_object_lookup().
@@ -695,26 +695,56 @@ static int objects_lookup(struct drm_file *filp, u32 *handle, int count,
  * failure. 0 is returned on success.
  *
  */
-int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
+int drm_gem_objects_lookup(struct drm_file *filp, u32 *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;
 
+	ret = objects_lookup(filp, bo_handles, count, objs);
+	if (ret)
+		kvfree(objs);
+	else
+		*objs_out = objs;
+
+	return ret;
+
+}
+EXPORT_SYMBOL(drm_gem_objects_lookup);
+
+/**
+ * drm_gem_objects_lookup_user - 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_user(struct drm_file *filp, void __user *bo_handles,
+				int count, struct drm_gem_object ***objs_out)
+{
+	int ret;
+	u32 *handles;
+
 	handles = kvmalloc_array(count, sizeof(u32), GFP_KERNEL);
-	if (!handles) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!handles)
+		return -ENOMEM;
 
 	if (copy_from_user(handles, bo_handles, count * sizeof(u32))) {
 		ret = -EFAULT;
@@ -722,15 +752,14 @@ int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
 		goto out;
 	}
 
-	ret = objects_lookup(filp, handles, count, objs);
-	*objs_out = objs;
+	ret = drm_gem_objects_lookup(filp, handles, count, objs_out);
 
 out:
 	kvfree(handles);
 	return ret;
 
 }
-EXPORT_SYMBOL(drm_gem_objects_lookup);
+EXPORT_SYMBOL(drm_gem_objects_lookup_user);
 
 /**
  * drm_gem_object_lookup - look up a GEM object from its handle
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index d74442d71048..486ca51d5662 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -130,9 +130,9 @@ panfrost_lookup_bos(struct drm_device *dev,
 	if (!job->implicit_fences)
 		return -ENOMEM;
 
-	return drm_gem_objects_lookup(file_priv,
-				      (void __user *)(uintptr_t)args->bo_handles,
-				      job->bo_count, &job->bos);
+	return drm_gem_objects_lookup_user(file_priv,
+					   (void __user *)(uintptr_t)args->bo_handles,
+					   job->bo_count, &job->bos);
 }
 
 /**
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 6aaba14f5972..354fc8d240e4 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -387,8 +387,10 @@ 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 drm_gem_objects_lookup(struct drm_file *filp, u32 *bo_handles,
 			   int count, struct drm_gem_object ***objs_out);
+int drm_gem_objects_lookup_user(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_dma_resv_wait(struct drm_file *filep, u32 handle,
 				    bool wait_all, unsigned long timeout);
-- 
2.17.1