Re: [PATCH 4/9] usb: phy: am335x-control: prevent module from being unloaded when in use

From: Felipe Balbi
Date: Fri Jul 18 2014 - 09:50:57 EST


On Fri, Jul 18, 2014 at 11:31:25AM +0200, Lothar Waßmann wrote:
> This patch fixes the real cause of the crash that was "fixed" by
> commit 7adb5c876e9c usb: musb: Fix panic upon musb_am335x module removal
>
> Signed-off-by: Lothar Waßmann <LW@xxxxxxxxxxxxxxxxxxx>

what is the "real cause of the crash" ? You don't explain that here.

> ---
> drivers/usb/phy/phy-am335x-control.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/usb/phy/phy-am335x-control.c b/drivers/usb/phy/phy-am335x-control.c
> index 35b6083..df3e1ba 100644
> --- a/drivers/usb/phy/phy-am335x-control.c
> +++ b/drivers/usb/phy/phy-am335x-control.c
> @@ -140,6 +140,9 @@ static int am335x_control_usb_probe(struct platform_device *pdev)
> const struct of_device_id *of_id;
> const struct phy_control *phy_ctrl;
>
> + if (!try_module_get(pdev->dev.parent->driver->owner))
> + return -EPROBE_DEFER;
> +
> of_id = of_match_node(omap_control_usb_id_table, pdev->dev.of_node);
> if (!of_id)
> return -EINVAL;
> @@ -171,8 +174,15 @@ static int am335x_control_usb_probe(struct platform_device *pdev)
> return 0;
> }
>
> +static int am335x_control_usb_remove(struct platform_device *pdev)
> +{
> + module_put(pdev->dev.parent->driver->owner);
> + return 0;
> +}

I can't see how this can make any difference. Care to explain ?

--
balbi

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