[PATCH net-next] net: core: recursively find netdev by device node

[PATCH net-next] net: core: recursively find netdev by device node

[Tobias Waldekranz]

The assumption that a device node is associated either with the
netdev's device, or the parent of that device, does not hold for all
drivers. E.g. Freescale's DPAA has two layers of platform devices
above the netdev. Instead, recursively walk up the tree from the
netdev, allowing any parent to match against the sought after node.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 net/core/net-sysfs.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 880e89c894f6..e353b822bb15 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1805,12 +1805,12 @@ static struct class net_class __ro_after_init = {
 #ifdef CONFIG_OF_NET
 static int of_dev_node_match(struct device *dev, const void *data)
 {
-	int ret = 0;
-
-	if (dev->parent)
-		ret = dev->parent->of_node == data;
+	for (; dev; dev = dev->parent) {
+		if (dev->of_node == data)
+			return 1;
+	}
 
-	return ret == 0 ? dev->of_node == data : ret;
+	return 0;
 }
 
 /*
-- 
2.17.1

Re: [PATCH net-next] net: core: recursively find netdev by device node

[Florian Fainelli]

On 5/15/2020 2:52 AM, Tobias Waldekranz wrote:
> The assumption that a device node is associated either with the
> netdev's device, or the parent of that device, does not hold for all
> drivers. E.g. Freescale's DPAA has two layers of platform devices
> above the netdev. Instead, recursively walk up the tree from the
> netdev, allowing any parent to match against the sought after node.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Humm, yes I tried to solve this differently before within the Freescale
FMAN driver before and it failed miserably, so I suppose this is as good
as it can be:

a1a50c8e4c241a505b7270e1a3c6e50d94e794b1 ("fsl/man: Inherit parent
device and of_node") later reverted with
48167c9ce0b91c068430345bf039c7be23fa2f3f ("fsl/fman: remove of_node")

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH net-next] net: core: recursively find netdev by device node

[David Miller]

From: Tobias Waldekranz <tobias@waldekranz.com>
Date: Fri, 15 May 2020 11:52:52 +0200

> The assumption that a device node is associated either with the
> netdev's device, or the parent of that device, does not hold for all
> drivers. E.g. Freescale's DPAA has two layers of platform devices
> above the netdev. Instead, recursively walk up the tree from the
> netdev, allowing any parent to match against the sought after node.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Applied, thanks Tobias.