Re: [LUG] Tasklets

[John Daragon <john@xxxxxxxxxx>]

Robin Cornelius wrote:
> > > Yes its perfectly feasable, its all gpl and on sourceforge in a cvs tree. 
>
> So I 
>
> > > can either post sections of offending code or you can have a browse of the 
> > > tree directly. What is simplest?
> >
> > Offending code is probably easiest. I didn't get to bed last night and 
> > I'm not firing on all cylinders...
>
>
>
> Ok here goes its quite a bit of code but it is the important bits.
> rt2x00_interrupt_rxdone is called from a master interupt handler that reads a 
> bit mask on the device to determine what interrupt routine to fire, that 
> (master handler) is protected with a spin_lock_irq_save() and 
> spin_lock_irq_restore(). 

BIG Snip...

>         /* Schedule rx packet processing. */
>         if(!skb_queue_empty(&adapter->rx_packet_queue))
>                 tasklet_schedule(&adapter->rx_tasklet);
>
>         spin_unlock(&adapter->rx_lock);
> }

snip ...

> If i replace the tasklet_schedule with a *direct* call to the tasklet handler 
> then all that code works. But left as is here the tasklets don't fire and a 
> big crash is encountered at some point later.

So tasklet_schedule() *is* being called.  And I presume there's no other 
invocation of tasklet_disable() anywhere so that the disable count is 
zero at this stage...

Actually, what I'm trying to say is : "Is

(0 == adapter->rx_tasklet.count)

at this juncture ?"

tasklet_schedule just puts it on the head of the per-cpu tasklet list, 
so if it's called (which it seems to be from your direct call mod...) 
then this *must* work,

tasklet_action() can only fail if it a) fails to lock the tasklet (ie 
(TASKLET_STATE_RUN == rx_tasklet.state) , or b) the tasklet disable 
count is non-zero.

Or, as experience has taught me to add to the end of any smartarse 
opinion, something else is going on...

jd

--

John Daragon                                          john@xxxxxxxxxx
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