Subject: [PATCH, resend] clk: get matching entry under lock in of_clk_init()

From: [email-masked] (Mike Turquette)
Date: Tue, 27 Aug 2013 16:06:24 -0700

Quoting Alex Elder (2013-08-22 09:31:31)
> Currently of_clk_init() finds a matching device node while holding
> the device tree spinlock.  When a matching device node is found, the
> lock is dropped and then re-acquired in order to get a reference
> to the matching device id structure.
> 
> Acquiring the spinlock twice is unnecessary (and it opens a
> vulnerable window that could conceivably lead to errors).
> 
> There already exists an interface for both finding and taking a
> reference to a device id under lock, so use it.
> 
> Signed-off-by: Alex Elder <[email-masked]>
> Reviewed-by: Christian Daudt <[email-masked]>
> Reviewed-by: Markus Mayer <[email-masked]>
> Reviewed-by: Matt Porter <[email-masked]>

Thanks for the fix. Taken into clk-next.

Regards,
Mike

> ---
>  drivers/clk/clk.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 56a00db..760ab1d 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -2116,13 +2116,13 @@ EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
>   */
>  void __init of_clk_init(const struct of_device_id *matches)
>  {
> +       const struct of_device_id *match;
>         struct device_node *np;
> 
>         if (!matches)
>                 matches = __clk_of_table;
> 
> -       for_each_matching_node(np, matches) {
> -               const struct of_device_id *match = of_match_node(matches, np);
> +       for_each_matching_node_and_match(np, matches, &match) {
>                 of_clk_init_cb_t clk_init_cb = match->data;
>                 clk_init_cb(np);
>         }
> -- 
> 1.7.9.5