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SubjectRe: [PATCH 3/4] drivers/net/can/mscan/mpc5xxx_can.c: Add of_node_put to avoid memory leak
Add a call to of_node_put in the error handling code following a call to
of_find_matching_node.

This patch also moves the existing call to of_node_put after the call to
iounmap in the error handling code, to make it possible to jump to
of_node_put without doing iounmap. These appear to be disjoint operations,
so the ordering doesn't matter.

This patch furthermore changes the -ENODEV result in the error handling
code for of_find_matching_node to a return of 0, as found in the error
handling code for of_iomap, because the return type of the function is
unsigned.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
local idexpression x;
expression E,E1,E2;
statement S;
@@

*x =
(of_find_node_by_path
|of_find_node_by_name
|of_find_node_by_phandle
|of_get_parent
|of_get_next_parent
|of_get_next_child
|of_find_compatible_node
|of_match_node
|of_find_node_by_type
|of_find_node_with_property
|of_find_matching_node
|of_parse_phandle
)(...);
...
if (x == NULL) S
<... when != x = E
*if (...) {
... when != of_node_put(x)
when != if (...) { ... of_node_put(x); ... }
(
return <+...x...+>;
* return ...;
)
}
...>
(
E2 = x;
of_node_put(x);
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
drivers/net/can/mscan/mpc5xxx_can.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
--- a/drivers/net/can/mscan/mpc5xxx_can.c
+++ b/drivers/net/can/mscan/mpc5xxx_can.c
@@ -143,12 +143,12 @@ static u32 __devinit mpc512x_can_get_clock(struct platform_device *ofdev,
np_clock = of_find_matching_node(NULL, mpc512x_clock_ids);
if (!np_clock) {
dev_err(&ofdev->dev, "couldn't find clock node\n");
- return -ENODEV;
+ return 0;
}
clockctl = of_iomap(np_clock, 0);
if (!clockctl) {
dev_err(&ofdev->dev, "couldn't map clock registers\n");
- return 0;
+ goto exit_put;
}

/* Determine the MSCAN device index from the physical address */
@@ -233,9 +233,9 @@ static u32 __devinit mpc512x_can_get_clock(struct platform_device *ofdev,
clocksrc == 1 ? "ref_clk" : "sys_clk", clockdiv);

exit_unmap:
- of_node_put(np_clock);
iounmap(clockctl);
-
+exit_put:
+ of_node_put(np_clock);
return freq;
}
#else /* !CONFIG_PPC_MPC512x */

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