Re: kue0 not receiving patch

[Scott Michel <scottm@xxxxxxxx>]

Matthew Dillon wrote:
>     Hmm.  That doesn't look quite right.... the mbuf is being put on the
>     ifq but then it is also being passed to NETISR_USB.   NETISR_USB
>     (usbintr() in usb/usb_ethersubr.c) takes the passed mbuf and 
>     IF_DEQUEUE's it... so far so good.  But then it *LOOPS* on the ifq
>     to get the next mbuf... but that means the same mbuf may be IF_DEQUEUE'd
>     more then once since the other mbufs on the ifq also had an ISR queued
>     for them.

If usbintr gets called multiple times, it will find an empty queue. The 
loops empties out the queue, leaving no work the next time usbintr gets 
called.

>     It sounds like if more then one packet is queued to the NETISR, the 
>     system ought to crash :-(.

It doesn't. It will panic on shutdown, but after disks are sync-ed for 
completely different reasons.

>     It seems to me that instead of IF_ENQUEUE'ing the mbuf in 
>     usb_ether_input() and usb_tx_done() we should have the usbintr() code
>     not try to dequeue it.

There should be two functions, usbintr_rx and usbintr_tx. The messaging 
functions already create an implicit queue for us, so why not take 
advantage of it? But at least this patch gets me operational enough, so 
I can actually set up a proper CVS repo and generate proper diffs and a 
proper solution.


-scooter