media: v4l2-ctrls: alloc arrays in ctrl_ref

Also allocate space for arrays in struct ctrl_ref.

This is in preparation for allowing to change the array size from
a driver.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/v4l2-core/v4l2-ctrls-api.c

@@ -467,7 +467,7 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
 
 			if (is_default)
 				ret = def_to_user(cs->controls + idx, ref->ctrl);
-			else if (is_request && ref->p_req_dyn_enomem)
+			else if (is_request && ref->p_req_array_enomem)
 				ret = -ENOMEM;
 			else if (is_request && ref->p_req_valid)
 				ret = req_to_user(cs->controls + idx, ref);

drivers/media/v4l2-core/v4l2-ctrls-core.c

@@ -1048,23 +1048,26 @@ void cur_to_new(struct v4l2_ctrl *ctrl)
 	ptr_to_ptr(ctrl, ctrl->p_cur, ctrl->p_new, ctrl->new_elems);
 }
 
-static bool req_alloc_dyn_array(struct v4l2_ctrl_ref *ref, u32 elems)
+static bool req_alloc_array(struct v4l2_ctrl_ref *ref, u32 elems)
 {
 	void *tmp;
 
-	if (elems < ref->p_req_dyn_alloc_elems)
+	if (elems == ref->p_req_array_alloc_elems)
+		return true;
+	if (ref->ctrl->is_dyn_array &&
+	    elems < ref->p_req_array_alloc_elems)
 		return true;
 
 	tmp = kvmalloc(elems * ref->ctrl->elem_size, GFP_KERNEL);
 
 	if (!tmp) {
-		ref->p_req_dyn_enomem = true;
+		ref->p_req_array_enomem = true;
 		return false;
 	}
-	ref->p_req_dyn_enomem = false;
+	ref->p_req_array_enomem = false;
 	kvfree(ref->p_req.p);
 	ref->p_req.p = tmp;
-	ref->p_req_dyn_alloc_elems = elems;
+	ref->p_req_array_alloc_elems = elems;
 	return true;
 }
 
@@ -1077,7 +1080,7 @@ void new_to_req(struct v4l2_ctrl_ref *ref)
 		return;
 
 	ctrl = ref->ctrl;
-	if (ctrl->is_dyn_array && !req_alloc_dyn_array(ref, ctrl->new_elems))
+	if (ctrl->is_array && !req_alloc_array(ref, ctrl->new_elems))
 		return;
 
 	ref->p_req_elems = ctrl->new_elems;
@@ -1094,7 +1097,7 @@ void cur_to_req(struct v4l2_ctrl_ref *ref)
 		return;
 
 	ctrl = ref->ctrl;
-	if (ctrl->is_dyn_array && !req_alloc_dyn_array(ref, ctrl->elems))
+	if (ctrl->is_array && !req_alloc_array(ref, ctrl->elems))
 		return;
 
 	ref->p_req_elems = ctrl->elems;
@@ -1123,14 +1126,18 @@ int req_to_new(struct v4l2_ctrl_ref *ref)
 		return 0;
 	}
 
-	/* Not a dynamic array, so just copy the request value */
-	if (!ctrl->is_dyn_array) {
+	/* Not an array, so just copy the request value */
+	if (!ctrl->is_array) {
 		ptr_to_ptr(ctrl, ref->p_req, ctrl->p_new, ctrl->new_elems);
 		return 0;
 	}
 
 	/* Sanity check, should never happen */
-	if (WARN_ON(!ref->p_req_dyn_alloc_elems))
+	if (WARN_ON(!ref->p_req_array_alloc_elems))
+		return -ENOMEM;
+
+	if (!ctrl->is_dyn_array &&
+	    ref->p_req_elems != ctrl->p_array_alloc_elems)
 		return -ENOMEM;
 
 	/*
@@ -1243,7 +1250,7 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
 	/* Free all nodes */
 	list_for_each_entry_safe(ref, next_ref, &hdl->ctrl_refs, node) {
 		list_del(&ref->node);
-		if (ref->p_req_dyn_alloc_elems)
+		if (ref->p_req_array_alloc_elems)
 			kvfree(ref->p_req.p);
 		kfree(ref);
 	}
@@ -1368,7 +1375,7 @@ int handler_new_ref(struct v4l2_ctrl_handler *hdl,
 	if (hdl->error)
 		return hdl->error;
 
-	if (allocate_req && !ctrl->is_dyn_array)
+	if (allocate_req && !ctrl->is_array)
 		size_extra_req = ctrl->elems * ctrl->elem_size;
 	new_ref = kzalloc(sizeof(*new_ref) + size_extra_req, GFP_KERNEL);
 	if (!new_ref)

include/media/v4l2-ctrls.h

@@ -318,15 +318,15 @@ struct v4l2_ctrl {
  *		from a cluster with multiple controls twice (when the first
  *		control of a cluster is applied, they all are).
  * @p_req_valid: If set, then p_req contains the control value for the request.
- * @p_req_dyn_enomem: If set, then p_req is invalid since allocating space for
- *		a dynamic array failed. Attempting to read this value shall
- *		result in ENOMEM. Only valid if ctrl->is_dyn_array is true.
- * @p_req_dyn_alloc_elems: The number of elements allocated for the dynamic
- *		array. Only valid if @p_req_valid and ctrl->is_dyn_array are
+ * @p_req_array_enomem: If set, then p_req is invalid since allocating space for
+ *		an array failed. Attempting to read this value shall
+ *		result in ENOMEM. Only valid if ctrl->is_array is true.
+ * @p_req_array_alloc_elems: The number of elements allocated for the
+ *		array. Only valid if @p_req_valid and ctrl->is_array are
  *		true.
  * @p_req_elems: The number of elements in @p_req. This is the same as
  *		ctrl->elems, except for dynamic arrays. In that case it is in
- *		the range of 1 to @p_req_dyn_alloc_elems. Only valid if
+ *		the range of 1 to @p_req_array_alloc_elems. Only valid if
  *		@p_req_valid is true.
  * @p_req:	If the control handler containing this control reference
  *		is bound to a media request, then this points to the
@@ -348,8 +348,8 @@ struct v4l2_ctrl_ref {
 	bool from_other_dev;
 	bool req_done;
 	bool p_req_valid;
-	bool p_req_dyn_enomem;
-	u32 p_req_dyn_alloc_elems;
+	bool p_req_array_enomem;
+	u32 p_req_array_alloc_elems;
 	u32 p_req_elems;
 	union v4l2_ctrl_ptr p_req;
 };