Subject: [PATCH] USB otg: use try_module_get in all usb_get_phy functions and add missing module_put

From: [email-masked] (Greg KH)
Date: Wed, 27 Feb 2013 08:21:46 -0800

On Wed, Feb 27, 2013 at 03:11:13PM +0100, Marc Kleine-Budde wrote:
> In patch "5d3c28b usb: otg: add device tree support to otg library"
> devm_usb_get_phy_by_phandle() was added. It uses try_module_get() to lock the
> phy driver in memory. The corresponding module_put() is missing in that patch.
> 
> This patch adds try_module_get() to usb_get_phy() and usb_get_phy_dev().
> Further the missing module_put() is added to usb_put_phy().
> 
> Reviewed-by: Kishon Vijay Abraham I <[email-masked]>
> Acked-by: Felipe Balbi <[email-masked]>
> Signed-off-by: Marc Kleine-Budde <[email-masked]>
> Signed-off-by: Michael Grzeschik <[email-masked]>
> ---
>  drivers/usb/otg/otg.c |   10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/otg/otg.c b/drivers/usb/otg/otg.c
> index e181439..2bd03d2 100644
> --- a/drivers/usb/otg/otg.c
> +++ b/drivers/usb/otg/otg.c
> @@ -130,7 +130,7 @@ struct usb_phy *usb_get_phy(enum usb_phy_type type)
>  	spin_lock_irqsave(&phy_lock, flags);
>  
>  	phy = __usb_find_phy(&phy_list, type);
> -	if (IS_ERR(phy)) {
> +	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {

Ugh, really?  We really are trying this type of module locking mess?

Why?  What is it solving?  What's wrong with having the module be able
to be unloaded whenever it wants to?  No one should be doing that and
expecting that their hardware would still work properly, right?

I really don't like this type of thing, sorry.

greg k-h