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authorHans Verkuil <hans.verkuil@cisco.com>2014-01-17 08:25:26 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2014-07-17 11:57:16 -0300
commit9ea1b7a4b66fddfab9e65e243b72d18371f8d9a5 (patch)
treefd8a4887e9fafdd171cb734430511e5a67bf2844 /drivers/media/v4l2-core
parent000e4f9a5bcf86fb52914c445ce5634b65e910a2 (diff)
downloadlinux-9ea1b7a4b66fddfab9e65e243b72d18371f8d9a5.tar.gz
[media] v4l2-ctrls: compare values only once
When setting a control the control's new value is compared to the current
value twice: once by new_to_cur(), once by cluster_changed(). Not a big
deal when dealing with simple values, but it can be a problem when dealing
with compound types or arrays. So fix this: cluster_changed() sets the
has_changed flag, which is used by new_to_cur() instead of having to do
another compare.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Diffstat (limited to 'drivers/media/v4l2-core')
-rw-r--r--drivers/media/v4l2-core/v4l2-ctrls.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index e7e0beab7048..1b4d37ce4afe 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1424,8 +1424,11 @@ static void new_to_cur(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, u32 ch_flags)
 
 	if (ctrl == NULL)
 		return;
-	changed = !ctrl->type_ops->equal(ctrl, ctrl->p_cur, ctrl->p_new);
-	ptr_to_ptr(ctrl, ctrl->p_new, ctrl->p_cur);
+
+	/* has_changed is set by cluster_changed */
+	changed = ctrl->has_changed;
+	if (changed)
+		ptr_to_ptr(ctrl, ctrl->p_new, ctrl->p_cur);
 
 	if (ch_flags & V4L2_EVENT_CTRL_CH_FLAGS) {
 		/* Note: CH_FLAGS is only set for auto clusters. */
@@ -1462,17 +1465,19 @@ static void cur_to_new(struct v4l2_ctrl *ctrl)
    value that differs from the current value. */
 static int cluster_changed(struct v4l2_ctrl *master)
 {
-	int diff = 0;
+	bool changed = false;
 	int i;
 
-	for (i = 0; !diff && i < master->ncontrols; i++) {
+	for (i = 0; i < master->ncontrols; i++) {
 		struct v4l2_ctrl *ctrl = master->cluster[i];
 
 		if (ctrl == NULL)
 			continue;
-		diff = !ctrl->type_ops->equal(ctrl, ctrl->p_cur, ctrl->p_new);
+		ctrl->has_changed = !ctrl->type_ops->equal(ctrl,
+						ctrl->p_cur, ctrl->p_new);
+		changed |= ctrl->has_changed;
 	}
-	return diff;
+	return changed;
 }
 
 /* Control range checking */