Re: [15/15] dma-mapping: bypass indirect calls for dma-direct

From: Christoph Hellwig
Date: Sun Dec 16 2018 - 04:03:10 EST


On Sat, Dec 15, 2018 at 09:46:54AM -0800, Guenter Roeck wrote:
> Hi,
>
> On Fri, Dec 07, 2018 at 11:07:20AM -0800, Christoph Hellwig wrote:
> > Avoid expensive indirect calls in the fast path DMA mapping
> > operations by directly calling the dma_direct_* ops if we are using
> > the directly mapped DMA operations.
> >
>
> This patch results in arm64 boot failures. Reverting the patch fixes
> the problem. Bisect results are attached. Per logs, the system fails
> to instantiate the root device. Examples from two logs:

This patch should fix it, it has already been sent out Friday and
I'm just waiting for an ACK from the arm64 maintainers before
applying it:

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