linux-kernel - Re: [PATCH] of: Fix cpu node iterator to not ignore disabled cpu nodes

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Message-ID: <87o9b9dphd.fsf@concordia.ellerman.id.au>
Date:   Thu, 01 Nov 2018 22:08:46 +1100
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Rob Herring <robh@...nel.org>
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Christian Zigotzky <chzigotzky@...osoft.de>,
        Frank Rowand <frowand.list@...il.com>
Subject: Re: [PATCH] of: Fix cpu node iterator to not ignore disabled cpu nodes

Rob Herring <robh@...nel.org> writes:

> In most cases, nodes with 'status = "disabled";' are treated as if the
> node is not present though it is a common bug to forget to check that.
> However, cpu nodes are different in that "disabled" simply means offline
> and the OS can bring the CPU core online. Commit f1f207e43b8a ("of: Add
> cpu node iterator for_each_of_cpu_node()") followed the common behavior
> of ignoring disabled cpu nodes. This breaks some powerpc systems (at
> least NXP P50XX/e5500). Fix this by dropping the status check.
>
> Fixes: 651d44f9679c ("of: use for_each_of_cpu_node iterator")
> Fixes: f1f207e43b8a ("of: Add cpu node iterator for_each_of_cpu_node()")
> Reported-by: Michael Ellerman <mpe@...erman.id.au>
> Cc: Christian Zigotzky <chzigotzky@...osoft.de>
> Cc: Frank Rowand <frowand.list@...il.com>
> Signed-off-by: Rob Herring <robh@...nel.org>
> ---
>  drivers/of/base.c | 2 --
>  1 file changed, 2 deletions(-)

This fixes my machine, thanks.

Tested-by: Michael Ellerman <mpe@...erman.id.au>

It was actually originally reported to me by Christian, so also:

Reported-by: Christian Zigotzky <chzigotzky@...osoft.de>


cheers

> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index cc62da278663..e47c5ce6cd58 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -776,8 +776,6 @@ struct device_node *of_get_next_cpu_node(struct device_node *prev)
>  		if (!(of_node_name_eq(next, "cpu") ||
>  		      (next->type && !of_node_cmp(next->type, "cpu"))))
>  			continue;
> -		if (!__of_device_is_available(next))
> -			continue;
>  		if (of_node_get(next))
>  			break;
>  	}
> -- 
> 2.19.1