Re: [next-next v3 05/10] net: cdc_ncm: convert tasklets to use new tasklet_setup() API

[Jakub Kicinski <kuba@kernel.org>]

On Tue, 3 Nov 2020 13:02:26 +0530 Allen Pais wrote:
> >   
> >> @@ -815,7 +815,7 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
> >>   
> >>   	hrtimer_init(&ctx->tx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> >>   	ctx->tx_timer.function = &cdc_ncm_tx_timer_cb;
> >> -	tasklet_init(&ctx->bh, cdc_ncm_txpath_bh, (unsigned long)dev);
> >> +	tasklet_setup(&ctx->bh, cdc_ncm_txpath_bh);
> >>   	atomic_set(&ctx->stop, 0);
> >>   	spin_lock_init(&ctx->mtx);
> >>   
> >> @@ -1468,9 +1468,9 @@ static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *timer)
> >>   	return HRTIMER_NORESTART;
> >>   }
> >>   
> >> -static void cdc_ncm_txpath_bh(unsigned long param)
> >> +static void cdc_ncm_txpath_bh(struct tasklet_struct *t)
> >>   {
> >> -	struct usbnet *dev = (struct usbnet *)param;
> >> +	struct usbnet *dev = from_tasklet(dev, t, bh);
> >>   	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
> >>   
> >>   	spin_lock_bh(&ctx->mtx);  
> > 
> > This one is wrong.
> > 
> > ctx is struct cdc_ncm_ctx, but you from_tasklet() struct usbdev.
> > They both happen to have a tasklet called bh in 'em.  
> 
>   from_tasklet() is struct usbnet. So it should pick the right bh isn't it?

Look at the tasklet_init / tasklet_setup line.

It used to pass dev as an argument. But the tasklet is in ctx.

Now there is no explicit param, do you gotta pick out of ctx.