linux-kernel - Re: [RESEND] phy: core: Get a refcount to phy in devm_of_phy_get_by

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Message-ID: <20151117140026.270a408e@xhacker>
Date:	Tue, 17 Nov 2015 14:00:26 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Chunfeng Yun <chunfeng.yun@...iatek.com>
CC:	Kishon Vijay Abraham I <kishon@...com>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	Daniel Kurtz <djkurtz@...omium.org>,
	<linux-mediatek@...ts.infradead.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Arun Ramamurthy <arun.ramamurthy@...adcom.com>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RESEND] phy: core: Get a refcount to phy in
 devm_of_phy_get_by_index()

Hi,

On Tue, 17 Nov 2015 13:56:48 +0800
Chunfeng Yun <chunfeng.yun@...iatek.com> wrote:

> On driver detach, devm_phy_release() will put a refcount to
> the phy, so gets a refconut to it before return.
> 
> Change-Id: I56fe428bf945f19c38d56245978c8ca17340eb2c

This line need to be removed



> Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
> ---
>  drivers/phy/phy-core.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index fc48fac..8c7f27d 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -636,8 +636,9 @@ EXPORT_SYMBOL_GPL(devm_of_phy_get);
>   * @np: node containing the phy
>   * @index: index of the phy
>   *
> - * Gets the phy using _of_phy_get(), and associates a device with it using
> - * devres. On driver detach, release function is invoked on the devres data,
> + * Gets the phy using _of_phy_get(), then gets a refcount to it,
> + * and associates a device with it using devres. On driver detach,
> + * release function is invoked on the devres data,
>   * then, devres data is freed.
>   *
>   */
> @@ -651,13 +652,21 @@ struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
>  		return ERR_PTR(-ENOMEM);
>  
>  	phy = _of_phy_get(np, index);
> -	if (!IS_ERR(phy)) {
> -		*ptr = phy;
> -		devres_add(dev, ptr);
> -	} else {
> +	if (IS_ERR(phy)) {
>  		devres_free(ptr);
> +		return phy;
>  	}
>  
> +	if (!try_module_get(phy->ops->owner)) {
> +		devres_free(ptr);
> +		return ERR_PTR(-EPROBE_DEFER);
> +	}
> +
> +	get_device(&phy->dev);
> +
> +	*ptr = phy;
> +	devres_add(dev, ptr);
> +
>  	return phy;
>  }
>  EXPORT_SYMBOL_GPL(devm_of_phy_get_by_index);

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