[PATCH] block: partitions: fix of_node refcount leak in of_partition()

[Wentao Liang <vulab@iscas.ac.cn>]

of_partition() calls of_node_get() on the parent device node at the
beginning of the function, storing the reference in 'partitions_np'.
This reference is leaked in two paths:

1. The compatibility check at the top of the function returns 0
   without releasing partitions_np when the node exists but is not
   "fixed-partitions" compatible.

2. The function returns 1 at the end after successfully processing
   all partitions without releasing partitions_np.

Fix both leaks by adding of_node_put(partitions_np) on each path.

Fixes: 2e3a191e89f9 ("block: add support for partition table defined in OF")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
 block/partitions/of.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/partitions/of.c b/block/partitions/of.c
index c22b60661098..53664ea06b65 100644
--- a/block/partitions/of.c
+++ b/block/partitions/of.c
@@ -74,8 +74,10 @@ int of_partition(struct parsed_partitions *state)
 	struct device_node *partitions_np = of_node_get(ddev->of_node);
 
 	if (!partitions_np ||
-	    !of_device_is_compatible(partitions_np, "fixed-partitions"))
+	    !of_device_is_compatible(partitions_np, "fixed-partitions")) {
+		of_node_put(partitions_np);
 		return 0;
+	}
 
 	slot = 1;
 	/* Validate parition offset and size */
@@ -104,5 +106,6 @@ int of_partition(struct parsed_partitions *state)
 
 	seq_buf_puts(&state->pp_buf, "\n");
 
+	of_node_put(partitions_np);
 	return 1;
 }
-- 
2.34.1