* Re: [PATCH] powerpc/pasemi: Use of_root in pas_pci_init()
[not found] ` <ebe8fdbb-c707-eb18-eef2-c37208642a77@csgroup.eu>
@ 2022-09-06 11:38 ` Michael Ellerman
0 siblings, 0 replies; only message in thread
From: Michael Ellerman @ 2022-09-06 11:38 UTC (permalink / raw)
To: Christophe Leroy, linuxppc-dev@lists.ozlabs.org, devicetree
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 06/09/2022 à 03:03, Michael Ellerman a écrit :
>> Currently in pas_pci_init() a reference to the root node is leaked due
>> to a missing of_node_put(). Instead just use of_root directly.
>>
>> Note that converting to of_find_compatible_node(NULL, ...) would
>> not be entirely equivalent, because that would check the compatible
>> property of the root node, whereas using of_root skips checking the root
>> node and start the search at the first child of the root.
>>
>
> That seems to simplify code. Should we do the same in all places below ?
I guess so.
There are some places where using of_root complicates things, because it
*doesn't* need refcount handling, eg. the cases in numa.c.
But in most cases it is preferable to use of_root IMHO.
cheers
> $ git grep -n "of_find_node_by_path(\"/\");" arch/powerpc/
> arch/powerpc/kernel/pci_32.c:139: dn = of_find_node_by_path("/");
> arch/powerpc/kernel/pci_32.c:214: dn = of_find_node_by_path("/");
> arch/powerpc/kernel/setup-common.c:212: root = of_find_node_by_path("/");
> arch/powerpc/kernel/setup-common.c:793: np = of_find_node_by_path("/");
> arch/powerpc/mm/numa.c:388: root = of_find_node_by_path("/");
> arch/powerpc/mm/numa.c:456: root = of_find_node_by_path("/");
> arch/powerpc/platforms/52xx/efika.c:77: root = of_find_node_by_path("/");
> arch/powerpc/platforms/52xx/efika.c:148: root = of_find_node_by_path("/");
> arch/powerpc/platforms/85xx/xes_mpc85xx.c:119: root = of_find_node_by_path("/");
> arch/powerpc/platforms/cell/setup.c:67: root = of_find_node_by_path("/");
> arch/powerpc/platforms/cell/setup.c:154: struct device_node *root > = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/pci.c:191: struct device_node *root = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/pci.c:216: struct device_node *root = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/setup.c:105: root = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/setup.c:201: root = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/setup.c:268: node = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/setup.c:299: struct device_node *root > = of_find_node_by_path("/");
> arch/powerpc/platforms/chrp/setup.c:378: root = of_find_node_by_path("/");
> arch/powerpc/platforms/maple/pci.c:601: root = of_find_node_by_path("/");
> arch/powerpc/platforms/maple/setup.c:225: root = of_find_node_by_path("/");
> arch/powerpc/platforms/pasemi/pci.c:276: root = of_find_node_by_path("/");
> arch/powerpc/platforms/pasemi/setup.c:268: root = of_find_node_by_path("/");
> arch/powerpc/platforms/powermac/pci.c:910: root = of_find_node_by_path("/");
> arch/powerpc/platforms/powermac/setup.c:105: np = of_find_node_by_path("/");
> arch/powerpc/platforms/powernv/setup.c:255: root = of_find_node_by_path("/");
> arch/powerpc/platforms/ps3/os-area.c:676: node = of_find_node_by_path("/");
> arch/powerpc/platforms/ps3/os-area.c:774: node = of_find_node_by_path("/");
> arch/powerpc/platforms/pseries/hotplug-memory.c:166: parent = of_find_node_by_path("/");
> arch/powerpc/platforms/pseries/ibmebus.c:187: root = of_find_node_by_path("/");
> arch/powerpc/platforms/pseries/lparcfg.c:232: root = of_find_node_by_path("/");
> arch/powerpc/platforms/pseries/lparcfg.c:799: rootdn = of_find_node_by_path("/");
> arch/powerpc/platforms/pseries/setup.c:97: root = of_find_node_by_path("/");
> arch/powerpc/platforms/pseries/setup.c:486: struct device_node *root > = of_find_node_by_path("/");
> arch/powerpc/sysdev/xive/spapr.c:714: rootdn = of_find_node_by_path("/");
>
> Christophe
>
>
>> Reported-by: Liang He <windhl@126.com>
>> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
>> ---
>> arch/powerpc/platforms/pasemi/pci.c | 10 ++--------
>> 1 file changed, 2 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pasemi/pci.c b/arch/powerpc/platforms/pasemi/pci.c
>> index 55f0160910bf..f27d31414737 100644
>> --- a/arch/powerpc/platforms/pasemi/pci.c
>> +++ b/arch/powerpc/platforms/pasemi/pci.c
>> @@ -270,18 +270,12 @@ static int __init pas_add_bridge(struct device_node *dev)
>>
>> void __init pas_pci_init(void)
>> {
>> - struct device_node *np, *root;
>> + struct device_node *np;
>> int res;
>>
>> - root = of_find_node_by_path("/");
>> - if (!root) {
>> - pr_crit("pas_pci_init: can't find root of device tree\n");
>> - return;
>> - }
>> -
>> pci_set_flags(PCI_SCAN_ALL_PCIE_DEVS);
>>
>> - np = of_find_compatible_node(root, NULL, "pasemi,rootbus");
>> + np = of_find_compatible_node(of_root, NULL, "pasemi,rootbus");
>> if (np) {
>> res = pas_add_bridge(np);
>> of_node_put(np);
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