[PATCH/REPOST] net/mpc5200: Fix locking on fec_mpc52xx driver

Grant Likely grant.likely at secretlab.ca
Wed Dec 9 16:16:36 EST 2009

On Tue, Dec 8, 2009 at 9:28 PM, David Miller <davem at davemloft.net> wrote:
> From: Grant Likely <grant.likely at secretlab.ca>
> Date: Fri, 04 Dec 2009 21:33:13 -0700
>> Fix the locking scheme on the fec_mpc52xx driver.  This device can
>> receive IRQs from three sources; the FEC itself, the tx DMA, and the
>> rx DMA.  Mutual exclusion was handled by taking a spin_lock() in the
>> critical regions, but because the handlers are run with IRQs enabled,
>> spin_lock() is insufficient and the driver can end up interrupting
>> a critical region anyway from another IRQ.
>> Asier Llano discovered that this occurs when an error IRQ is raised
>> in the middle of handling rx irqs which resulted in an sk_buff memory
>> leak.
> I'll apply this fix.


> But, longer term, it's a thousand times easier and more efficient to
> move the processing of these interrupts into softirq context.

I agree.  Just need to find someone to do it.


Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.

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