Re: [RFC PATCH] OF: fix of_find_node_by_path() assumption that of_allnodes is root

[Rob Herring]

On Fri, Jun 13, 2014 at 12:53 AM, Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> From: Frank Rowand <frank.rowand@xxxxxxxxxxxxxx>
>
> Pantelis Antoniou reports that of_find_node_by_path() is borked because
> of_allnodes is not guaranteed to contain the root of the tree after using
> any of the dynamic update functions because some other nodes ends up as
> of_allnodes.
>
> Fixes: c22e650e66b8 of: Make of_find_node_by_path() handle /aliases

Is it not possible to do a fix in of_find_node_by_path instead? I just
wonder if this could have any other unintended side-effects on
of_attach_node's behavior.

Rob

>
> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxxxxx>
> ---
>
>
> Pantelis,
>
> Can you test whether the problem you reported in irc?
>
> This patch has not been tested, not even compile tested.
>
>
>  drivers/of/base.c |    8       6 +     2 -     0 !
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> Index: b/drivers/of/base.c
> ===================================================================
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -1948,6 +1948,9 @@ int of_reconfig_notify(unsigned long act
>
>  /**
>   * of_attach_node - Plug a device node into the tree and global list.
> + *
> + * Put the device node after of_allnodes in the global list so that
> + * of_allnodes remains the root.
>   */
>  int of_attach_node(struct device_node *np)
>  {
> @@ -1958,11 +1961,12 @@ int of_attach_node(struct device_node *n
>         if (rc)
>                 return rc;
>
> +       BUG_ON(!of_allnodes);
>         raw_spin_lock_irqsave(&devtree_lock, flags);
>         np->sibling = np->parent->child;
> -       np->allnext = of_allnodes;
> +       np->allnext = of_allnodes->allnext;
>         np->parent->child = np;
> -       of_allnodes = np;
> +       of_allnodes->allnext = np;
>         of_node_clear_flag(np, OF_DETACHED);
>         raw_spin_unlock_irqrestore(&devtree_lock, flags);
>
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