of/irq: Fix device_node refcount in of_irq_parse_raw()

Commit 2361613206e6, "of/irq: Refactor interrupt-map parsing" changed
the refcount on the device_node causing an error in of_node_put():

ERROR: Bad of_node_put() on /pci@800000020000000
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-dirty #2
Call Trace:
[c00000003e403500] [c0000000000144fc] .show_stack+0x7c/0x1f0 (unreliable)
[c00000003e4035d0] [c00000000070f250] .dump_stack+0x88/0xb4
[c00000003e403650] [c0000000005e8768] .of_node_release+0xd8/0xf0
[c00000003e4036e0] [c0000000005eeafc] .of_irq_parse_one+0x10c/0x280
[c00000003e4037a0] [c0000000005efd4c] .of_irq_parse_pci+0x3c/0x1d0
[c00000003e403840] [c000000000038240] .pcibios_setup_device+0xa0/0x2e0
[c00000003e403910] [c0000000000398f0] .pcibios_setup_bus_devices+0x60/0xd0
[c00000003e403990] [c00000000003b3a4] .__of_scan_bus+0x1a4/0x2b0
[c00000003e403a80] [c00000000003a62c] .pcibios_scan_phb+0x30c/0x410
[c00000003e403b60] [c0000000009fe430] .pcibios_init+0x7c/0xd4

This patch adjusts the refcount in the walk of the interrupt tree.
When a match is found, there is no need to increase the refcount
on 'out_irq->np' as 'newpar' is already holding a ref. The refcount
balance between 'ipar' and 'newpar' is maintained in the skiplevel:
goto label.

This patch also removes the usage of the device_node variable 'old'
which seems useless after the latest changes.

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 786b0b47fae4..27212402c532 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -165,7 +165,6 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
                 if (of_get_property(ipar, "interrupt-controller", NULL) !=
                                 NULL) {
                         pr_debug(" -> got it !\n");
-                        of_node_put(old);
                         return 0;
                 }
 
@@ -250,8 +249,7 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
                  * Successfully parsed an interrrupt-map translation; copy new
                  * interrupt specifier into the out_irq structure
                  */
-                of_node_put(out_irq->np);
-                out_irq->np = of_node_get(newpar);
+                out_irq->np = newpar;
 
                 match_array = imap - newaddrsize - newintsize;
                 for (i = 0; i < newintsize; i++)
@@ -268,7 +266,6 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
         }
  fail:
         of_node_put(ipar);
-        of_node_put(out_irq->np);
         of_node_put(newpar);
 
         return -EINVAL;