[PATCH] driver: net: can: delete napi if register_candev fails

[PATCH] driver: net: can: delete napi if register_candev fails

[Dongliang Mu]

If register_candev fails, xcan_probe does not clean the napi
created by netif_napi_add.

Fix this by adding error handling code to clean napi when
register_candev fails.

Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
 drivers/net/can/xilinx_can.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index 3b883e607d8b..6ee0b5a8cdfc 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -1807,7 +1807,7 @@ static int xcan_probe(struct platform_device *pdev)
 	ret = register_candev(ndev);
 	if (ret) {
 		dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
-		goto err_disableclks;
+		goto err_del_napi;
 	}
 
 	devm_can_led_init(ndev);
@@ -1825,6 +1825,8 @@ static int xcan_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_del_napi:
+	netif_napi_del(&priv->napi);
 err_disableclks:
 	pm_runtime_put(priv->dev);
 	pm_runtime_disable(&pdev->dev);
-- 
2.25.1

Re: [PATCH] driver: net: can: delete napi if register_candev fails

[Dongliang Mu]

On Wed, Oct 13, 2021 at 12:04 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
>
> If register_candev fails, xcan_probe does not clean the napi
> created by netif_napi_add.
>

It seems the netif_napi_del operation is done in the free_candev
(free_netdev precisely).

list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
          netif_napi_del(p);

And list_add_rcu(&napi->dev_list, &dev->napi_list) is done in the
netif_napi_add.

Therefore, I suggest removing "netif_napi_del" operation in the
xcan_remove to match probe and remove function.

> Fix this by adding error handling code to clean napi when
> register_candev fails.
>
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>  drivers/net/can/xilinx_can.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
> index 3b883e607d8b..6ee0b5a8cdfc 100644
> --- a/drivers/net/can/xilinx_can.c
> +++ b/drivers/net/can/xilinx_can.c
> @@ -1807,7 +1807,7 @@ static int xcan_probe(struct platform_device *pdev)
>         ret = register_candev(ndev);
>         if (ret) {
>                 dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
> -               goto err_disableclks;
> +               goto err_del_napi;
>         }
>
>         devm_can_led_init(ndev);
> @@ -1825,6 +1825,8 @@ static int xcan_probe(struct platform_device *pdev)
>
>         return 0;
>
> +err_del_napi:
> +       netif_napi_del(&priv->napi);
>  err_disableclks:
>         pm_runtime_put(priv->dev);
>         pm_runtime_disable(&pdev->dev);
> --
> 2.25.1
>

Re: [PATCH] driver: net: can: delete napi if register_candev fails

[Marc Kleine-Budde]

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On 13.10.2021 13:21:09, Dongliang Mu wrote:
> On Wed, Oct 13, 2021 at 12:04 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
> >
> > If register_candev fails, xcan_probe does not clean the napi
> > created by netif_napi_add.
> >
> 
> It seems the netif_napi_del operation is done in the free_candev
> (free_netdev precisely).
> 
> list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
>           netif_napi_del(p);
> 
> And list_add_rcu(&napi->dev_list, &dev->napi_list) is done in the
> netif_napi_add.
> 
> Therefore, I suggest removing "netif_napi_del" operation in the
> xcan_remove to match probe and remove function.

Sounds reasonable, can you create a patch for this.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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Re: [PATCH] driver: net: can: delete napi if register_candev fails

[Dongliang Mu]

On Sun, Oct 17, 2021 at 8:36 PM Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 13.10.2021 13:21:09, Dongliang Mu wrote:
> > On Wed, Oct 13, 2021 at 12:04 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
> > >
> > > If register_candev fails, xcan_probe does not clean the napi
> > > created by netif_napi_add.
> > >
> >
> > It seems the netif_napi_del operation is done in the free_candev
> > (free_netdev precisely).
> >
> > list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
> >           netif_napi_del(p);
> >
> > And list_add_rcu(&napi->dev_list, &dev->napi_list) is done in the
> > netif_napi_add.
> >
> > Therefore, I suggest removing "netif_napi_del" operation in the
> > xcan_remove to match probe and remove function.
>
> Sounds reasonable, can you create a patch for this.

I have submitted one patch - https://lkml.org/lkml/2021/10/17/181

>
> regards,
> Marc
>
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
> Embedded Linux                   | https://www.pengutronix.de  |
> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

Re: [PATCH] driver: net: can: delete napi if register_candev fails

[Marc Kleine-Budde]

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On 17.10.2021 20:52:14, Dongliang Mu wrote:
> On Sun, Oct 17, 2021 at 8:36 PM Marc Kleine-Budde <mkl@pengutronix.de> wrote:
> >
> > On 13.10.2021 13:21:09, Dongliang Mu wrote:
> > > On Wed, Oct 13, 2021 at 12:04 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
> > > >
> > > > If register_candev fails, xcan_probe does not clean the napi
> > > > created by netif_napi_add.
> > > >
> > >
> > > It seems the netif_napi_del operation is done in the free_candev
> > > (free_netdev precisely).
> > >
> > > list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
> > >           netif_napi_del(p);
> > >
> > > And list_add_rcu(&napi->dev_list, &dev->napi_list) is done in the
> > > netif_napi_add.
> > >
> > > Therefore, I suggest removing "netif_napi_del" operation in the
> > > xcan_remove to match probe and remove function.
> >
> > Sounds reasonable, can you create a patch for this.
> 
> I have submitted one patch - https://lkml.org/lkml/2021/10/17/181

Thanks for the patch.

Regards,
Marc

BTW: Do you know the new kernel.org mailing list archive available at
https://lore.kernel.org ?
You can reference a mail using its Message-ID, in you case it's:
https://lore.kernel.org/all/20211017125022.3100329-1-mudongliangabcd@gmail.com

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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