drivers/hvc: Add missing of_node_put

of_node_put is needed before discarding a value received from
of_find_node_by_name, e.g., in error handling code or when the device
node is no longer used.

The semantic match that catches the bug is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression struct device_node *n;
position p1, p2;
statement S1,S2;
expression E,E1;
expression *ptr != NULL;
@@

(
if (!(n@p1 = of_find_node_by_name(...))) S1
|
n@p1 = of_find_node_by_name(...)
)
<... when != of_node_put(n)
    when != if (...) { <+... of_node_put(n) ...+> }
    when != true !n  || ...
    when != n = E
    when != E = n
if (!n || ...) S2
...>
(
  return \(0\|<+...n...+>\|ptr\);
|
return@p2 ...;
|
n = E1
|
E1 = n
)
@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s of_find_node_by_name %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>

Signed-off-by: Nicolas Palix <npalix@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/char/hvc_vio.c b/drivers/char/hvc_vio.c
index 019e0b58593d..bd62dc86b47d 100644
--- a/drivers/char/hvc_vio.c
+++ b/drivers/char/hvc_vio.c
@@ -153,8 +153,10 @@ static int hvc_find_vtys(void)
                 /* We have statically defined space for only a certain number
                  * of console adapters.
                  */
-                if (num_found >= MAX_NR_HVC_CONSOLES)
+                if (num_found >= MAX_NR_HVC_CONSOLES) {
+                        of_node_put(vty);
                         break;
+                }
 
                 vtermno = of_get_property(vty, "reg", NULL);
                 if (!vtermno)