linux-kernel - Re: [PATCH 4/5] pinctrl: rza1: Fix selector use for groups and functions

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Message-ID: <20180619041622.GA4956@w540>
Date:   Tue, 19 Jun 2018 06:16:22 +0200
From:   jacopo mondi <jacopo@...ndi.org>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Haojian Zhuang <haojian.zhuang@...aro.org>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Paul Cercueil <paul@...pouillou.net>,
        Sean Wang <sean.wang@...iatek.com>
Subject: Re: [PATCH 4/5] pinctrl: rza1: Fix selector use for groups and
 functions

Hi Tony,
   thanks for doing this!

I cannot find the original bug report in linux-gpio, so I'll comment
on this single patch only.

On Fri, Jun 15, 2018 at 04:11:40AM -0700, Tony Lindgren wrote:
> We must use a mutex around the generic_add functions and save the
> function and group selector in case we need to remove them. Otherwise
> the selector use will be racy for deferred probe at least.
>
> Fixes: 5a49b644b307 ("pinctrl: Renesas RZ/A1 pin and gpio controller")
> Reported-by: H. Nikolaus Schaller <hns@...delico.com>
> Cc: Haojian Zhuang <haojian.zhuang@...aro.org>
> Cc: Jacopo Mondi <jacopo+renesas@...ndi.org>
> Cc: Paul Cercueil <paul@...pouillou.net>
> Cc: Sean Wang <sean.wang@...iatek.com>
> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
>  drivers/pinctrl/pinctrl-rza1.c | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pinctrl/pinctrl-rza1.c b/drivers/pinctrl/pinctrl-rza1.c
> --- a/drivers/pinctrl/pinctrl-rza1.c
> +++ b/drivers/pinctrl/pinctrl-rza1.c
> @@ -1005,7 +1005,7 @@ static int rza1_dt_node_to_map(struct pinctrl_dev *pctldev,
>  	struct device_node *child;
>  	const char *grpname;
>  	const char **fngrps;
> -	int ret, npins;
> +	int ret, npins, gsel, fsel;

Nit: can you move this 3 lines up to keep the variable declarations in reverse
xmas tree order? or if you prefer declare one variable per line...

With this minor comment fixed:
Acked-by: Jacopo Mondi <jacopo@...ndi.org>

Thanks
   j

>
>  	npins = rza1_dt_node_pin_count(np);
>  	if (npins < 0) {
> @@ -1055,18 +1055,19 @@ static int rza1_dt_node_to_map(struct pinctrl_dev *pctldev,
>  	fngrps[0] = grpname;
>
>  	mutex_lock(&rza1_pctl->mutex);
> -	ret = pinctrl_generic_add_group(pctldev, grpname, grpins, npins,
> -					NULL);
> -	if (ret) {
> +	gsel = pinctrl_generic_add_group(pctldev, grpname, grpins, npins,
> +					 NULL);
> +	if (gsel < 0) {
>  		mutex_unlock(&rza1_pctl->mutex);
> -		return ret;
> +		return gsel;
>  	}
>
> -	ret = pinmux_generic_add_function(pctldev, grpname, fngrps, 1,
> -					  mux_confs);
> -	if (ret)
> +	fsel = pinmux_generic_add_function(pctldev, grpname, fngrps, 1,
> +					   mux_confs);
> +	if (fsel < 0) {
> +		ret = fsel;
>  		goto remove_group;
> -	mutex_unlock(&rza1_pctl->mutex);
> +	}
>
>  	dev_info(rza1_pctl->dev, "Parsed function and group %s with %d pins\n",
>  				 grpname, npins);
> @@ -1083,15 +1084,15 @@ static int rza1_dt_node_to_map(struct pinctrl_dev *pctldev,
>  	(*map)->data.mux.group = np->name;
>  	(*map)->data.mux.function = np->name;
>  	*num_maps = 1;
> +	mutex_unlock(&rza1_pctl->mutex);
>
>  	return 0;
>
>  remove_function:
> -	mutex_lock(&rza1_pctl->mutex);
> -	pinmux_generic_remove_last_function(pctldev);
> +	pinmux_generic_remove_function(pctldev, fsel);
>
>  remove_group:
> -	pinctrl_generic_remove_last_group(pctldev);
> +	pinctrl_generic_remove_group(pctldev, gsel);
>  	mutex_unlock(&rza1_pctl->mutex);
>
>  	dev_info(rza1_pctl->dev, "Unable to parse function and group %s\n",
> --
> 2.17.1

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