linux-kernel - Re: [PATCH v3 3/5] usb: r8a66597-udc: Use devm_clk_get

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Message-ID: <b439b38a-a37a-4734-afd8-736ce047b5d7@wanadoo.fr>
Date: Mon, 26 Aug 2024 22:27:48 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: liulei.rjpt@...o.com
Cc: gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
 linux-usb@...r.kernel.org, opensource.kernel@...o.com,
 u.kleine-koenig@...gutronix.de
Subject: Re: [PATCH v3 3/5] usb: r8a66597-udc: Use devm_clk_get_enabled()
 helpers

Le 26/08/2024 à 10:23, Lei Liu a écrit :
> The devm_clk_get_enabled() helpers:
>      - call devm_clk_get()
>      - call clk_prepare_enable() and register what is needed in order to
>       call clk_disable_unprepare() when needed, as a managed resource.
> 
> This simplifies the code and avoids calls to clk_disable_unprepare().
> 
> Signed-off-by: Lei Liu <liulei.rjpt-DGpbCiVdSXo@...lic.gmane.org>
> ---
>   drivers/usb/gadget/udc/r8a66597-udc.c | 16 ++++------------
>   1 file changed, 4 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/r8a66597-udc.c b/drivers/usb/gadget/udc/r8a66597-udc.c
> index db4a10a979f9..bdbe5ead741e 100644
> --- a/drivers/usb/gadget/udc/r8a66597-udc.c
> +++ b/drivers/usb/gadget/udc/r8a66597-udc.c
> @@ -1812,10 +1812,6 @@ static void r8a66597_remove(struct platform_device *pdev)
>   	usb_del_gadget_udc(&r8a66597->gadget);
>   	del_timer_sync(&r8a66597->timer);
>   	r8a66597_free_request(&r8a66597->ep[0].ep, r8a66597->ep0_req);
> -
> -	if (r8a66597->pdata->on_chip) {
> -		clk_disable_unprepare(r8a66597->clk);
> -	}
>   }
>   
>   static void nop_completion(struct usb_ep *ep, struct usb_request *r)
> @@ -1876,18 +1872,17 @@ static int r8a66597_probe(struct platform_device *pdev)
>   
>   	if (r8a66597->pdata->on_chip) {
>   		snprintf(clk_name, sizeof(clk_name), "usb%d", pdev->id);
> -		r8a66597->clk = devm_clk_get(dev, clk_name);
> +		r8a66597->clk = devm_clk_get_enabled(dev, clk_name);
>   		if (IS_ERR(r8a66597->clk)) {
>   			dev_err(dev, "cannot get clock \"%s\"\n", clk_name);
>   			return PTR_ERR(r8a66597->clk);
>   		}
> -		clk_prepare_enable(r8a66597->clk);
>   	}
>   
>   	if (r8a66597->pdata->sudmac) {
>   		ret = r8a66597_sudmac_ioremap(r8a66597, pdev);
>   		if (ret < 0)
> -			goto clean_up2;
> +			goto err_add_udc;

Hi,

Here and below, now we have an additional r8a66597_free_request() in the 
error handling path, even if r8a66597_alloc_request() was not called 
yet. + see my other comment below.

>   	}
>   
>   	disable_controller(r8a66597); /* make sure controller is disabled */
> @@ -1896,7 +1891,7 @@ static int r8a66597_probe(struct platform_device *pdev)
>   			       udc_name, r8a66597);
>   	if (ret < 0) {
>   		dev_err(dev, "request_irq error (%d)\n", ret);
> -		goto clean_up2;
> +		goto err_add_udc;
>   	}
>   
>   	INIT_LIST_HEAD(&r8a66597->gadget.ep_list);
> @@ -1939,7 +1934,7 @@ static int r8a66597_probe(struct platform_device *pdev)
>   							GFP_KERNEL);
>   	if (r8a66597->ep0_req == NULL) {
>   		ret = -ENOMEM;
> -		goto clean_up2;
> +		goto err_add_udc;
>   	}
>   	r8a66597->ep0_req->complete = nop_completion;
>   
> @@ -1952,9 +1947,6 @@ static int r8a66597_probe(struct platform_device *pdev)
>   
>   err_add_udc:
>   	r8a66597_free_request(&r8a66597->ep[0].ep, r8a66597->ep0_req);
> -clean_up2:
> -	if (r8a66597->pdata->on_chip)
> -		clk_disable_unprepare(r8a66597->clk);
>   
>   	if (r8a66597->ep0_req)
>   		r8a66597_free_request(&r8a66597->ep[0].ep, r8a66597->ep0_req);

This error handling path looks broken.
r8a66597_free_request() is called twice with the same arguments.

CJ