clk: fix new_parent dereference before null check

Commit 71472c0 (clk: add support for clock reparent on set_rate) added a
dereference of the new_parent pointer in clk_reparent(), but as detected
by smatch clk_reparent() later checks whether new_parent is NULL.

The dereference was in order to clear the new parent's new_child pointer
to avoid duplicate POST_RATE_CHANGE notifications, so clearly isn't
necessary if the new parent is NULL, so move it inside the "if
(new_parent)" block.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 2db08c01ef51d9de9b618282ba55134d97dfabe4..02e75d4e0a7765cb6cca6ba22602b569821442d7 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1108,16 +1108,17 @@ static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
 
 static void clk_reparent(struct clk *clk, struct clk *new_parent)
 {
-       /* avoid duplicate POST_RATE_CHANGE notifications */
-       if (new_parent->new_child == clk)
-               new_parent->new_child = NULL;
-
        hlist_del(&clk->child_node);
 
-       if (new_parent)
+       if (new_parent) {
+               /* avoid duplicate POST_RATE_CHANGE notifications */
+               if (new_parent->new_child == clk)
+                       new_parent->new_child = NULL;
+
                hlist_add_head(&clk->child_node, &new_parent->children);
-       else
+       } else {
                hlist_add_head(&clk->child_node, &clk_orphan_list);
+       }
 
        clk->parent = new_parent;
 }