Re: [patch] media: videobuf-dma-sg: Clear dma coherent buf only once

[Christoph Hellwig <hch@xxxxxx>]

On Thu, Mar 21, 2019 at 06:36:21PM +0800, Hillf Danton wrote:
> On both the arch and dma core sides, see commit 6829e274a623 and 518a2f1925c3
> respectively, efforts are paid for clearing memory returned from dma_alloc_*
> functions, so on the driver side we can get our duty offloaded by explicitly
> asking the dma core for a zero-ed buffer.

And why do you think you then need to pass __GFP_ZERO?