Re: [PATCH 1/6] dmaengine/dw_dmac: Replace spin_lock_bh with irqsavevariants

[viresh kumar]

On 04/27/2011 02:03 AM, Russell King - ARM Linux wrote:
> On Tue, Apr 19, 2011 at 11:55:45AM +0530, viresh kumar wrote:
>> This must have been added in dw_dma_chan instead :(
>> Will resend it.
> 
> Even that doesn't work.  It has to be a local variable.

Hello,

There are two kinds of locks taken in dw_dmac: spin_lock_bh and spin_lock.
spin_lock_bh is taken from routines called from external drivers and spin_lock
taken inside tasklet.
For reasons mentioned earlier, spin_lock_bh has to be replaced with spin_lock_irqsave.

Now, Is simple spin_lock() sufficient inside tasklet?? As dma API's can be called
from interrupt context (which will try to take spin_lock_irqsave).

I think spin_lock must be replaced with irqsave variants, even in tasklet.
Now if we do that, do we need this tasklet at all??

-- 
viresh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/