Re: [PATCH v2] dma: mmp_pdma: fix a memory alloc error

From: Xiang Wang
Date: Wed Jul 31 2013 - 22:27:52 EST


2013/7/29 Vinod Koul <vinod.koul@xxxxxxxxx>:
> On Thu, Jul 25, 2013 at 10:22:50AM +0800, Xiang Wang wrote:
>
> Btw its generally a good idea to remove the parts not required for further
> discussion
>
>> Would you please explain a little more about why we should use
>> GFP_NOWAIT here? This memory is not dedicated for DMA controller. Do
>> we have special reasons to use GFP_NOWAIT? Thanks!
> There are few reasons
> - the dma requests can be triggered from atomic context
> - so for above you can argue to use the GFP_ATOMIC and the guideline for dma
> drivers [1] was discussed briefly
>
> ~Vinod
> [1]: http://lkml.indiana.edu/hypermail/linux/kernel/0911.1/02316.html
>
> --
Hi, Vinod
Thanks for your explanation. But want to double confirm with you that
the memory alloc in my patch is in probe function, still need to use
GFP_NOWAIT? Thanks!

--
Regards,
Xiang
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