Re: NAPI note

["David S. Miller" <davem@xxxxxxxxxx>]

   From: Jeff Garzik <jgarzik@xxxxxxxxx>
   Date: Fri, 14 Feb 2003 18:58:13 -0500

   Manfred Spraul wrote:
   > It seems to be a generic NAPI restriction:
   > The caller of netif_receive_skb() must not own a spinlock that is 
   > acquired from an interrupt handler.
   
   Thanks much for noticing this, Manfred.

I think this logic is buggy.

In the example I've seen posted, only a NAPI implementation bug
could cause the situation to occur.

If cpu1 is in ->poll() for the driver, then by definition the
device shall not cause interrupts.  The device's interrupts
are disabled before we enter the ->poll() handler, and as such
the "cpu2 take device interrupt and takes driver->lock" cannot
occur.

If anything we've found a bug in interrupt disabling in the tg3
driver.