2.4.7 softirq incorrectness.

Rusty Russell (rusty@rustcorp.com.au)
Mon, 23 Jul 2001 06:44:10 +1000

This current code is bogus. Consider:
spin_lock_irqsave(flags);
cpu_raise_softirq(this_cpu, NET_RX_SOFTIRQ);
spin_unlock_irqrestore(flags);

Oops... softirq not run until the next interrupt. So, EITHER:

1) make local_irq_restore check for pending softirqs in as we do for
local_bh_enable(), and get rid of the wakeup_softirqd() in
cpu_raise_softirq(). ie. all "exits" from in_interrupt == true are
symmetrical.

*OR*

2) Change the check in cpu_raise_softirq to:
if (!in_hw_irq_handler(cpu))
wakeup_softirqd(cpu);

and implement in_hw_irq_handler() on all platforms. Then get rid of
the test in local_bh_enable().

Please pick one approach or the other, and stick with it! The current
code does half of each, badly. 8(

Thanks,
Rusty.

--
Premature optmztion is rt of all evl. --DK
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