[PATCH v2] clk: mvebu: ap-cpu: fix missing clk_put() in ap_cpu_clock_probe()

[Wentao Liang]

The function ap_cpu_clock_probe() calls of_clk_get() to obtain a
reference to the parent clock for each CPU cluster, but it never
releases it with clk_put().  The returned clk is used only to read
the parent's name via __clk_get_name(), and the reference is leaked
on every successful cluster initialization as well as on the error
path when devm_clk_hw_register() fails.

Rather than adding clk_put() calls, replace the of_clk_get() +
__clk_get_name() pattern with of_clk_get_parent_name(), which is
the intended API for this use case and handles the reference
counting internally.  This matches the pattern already used by the
sibling drivers clk-cpu.c and clk-corediv.c.

Fixes: af9617b419f7 ("clk: mvebu: ap-cpu-clk: Fix a memory leak in error handling paths")
Signed-off-by: Wentao Liang <vulab at iscas.ac.cn>
---
v2: Replace of_clk_get() + __clk_get_name() with of_clk_get_parent_name()
    as suggested by Brian Masney, instead of adding clk_put() calls.
    Also correct the Fixes: tag to point to the original commit that
    introduced the leak.
---
 drivers/clk/mvebu/ap-cpu-clk.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/mvebu/ap-cpu-clk.c b/drivers/clk/mvebu/ap-cpu-clk.c
index a8175908e353..1cf63c7a0bc3 100644
--- a/drivers/clk/mvebu/ap-cpu-clk.c
+++ b/drivers/clk/mvebu/ap-cpu-clk.c
@@ -288,7 +288,6 @@ static int ap_cpu_clock_probe(struct platform_device *pdev)
 		char *clk_name = "cpu-cluster-0";
 		struct clk_init_data init;
 		const char *parent_name;
-		struct clk *parent;
 		u64 cpu;
 
 		cpu = of_get_cpu_hwid(dn, 0);
@@ -304,13 +303,12 @@ static int ap_cpu_clock_probe(struct platform_device *pdev)
 		if (ap_cpu_data->hws[cluster_index])
 			continue;
 
-		parent = of_clk_get(np, cluster_index);
-		if (IS_ERR(parent)) {
-			dev_err(dev, "Could not get the clock parent\n");
+		parent_name = of_clk_get_parent_name(np, cluster_index);
+		if (!parent_name) {
+			dev_err(dev, "Could not get the clock parent name\n");
 			of_node_put(dn);
 			return -EINVAL;
 		}
-		parent_name =  __clk_get_name(parent);
 		clk_name[12] += cluster_index;
 		ap_cpu_clk[cluster_index].clk_name =
 			ap_cp_unique_name(dev, np->parent, clk_name);
@@ -328,11 +326,9 @@ static int ap_cpu_clock_probe(struct platform_device *pdev)
 		ret = devm_clk_hw_register(dev, &ap_cpu_clk[cluster_index].hw);
 		if (ret) {
 			of_node_put(dn);
-			clk_put(parent);
 			return ret;
 		}
 		ap_cpu_data->hws[cluster_index] = &ap_cpu_clk[cluster_index].hw;
-		clk_put(parent);
 	}
 
 	ap_cpu_data->num = cluster_index + 1;
-- 
2.34.1