Re: [RFC PATCH] crypto: flush poison data

[LABBE Corentin]

Le Tue, Jul 05, 2022 at 07:58:34PM +0200, Christoph Hellwig a écrit :
> On Tue, Jul 05, 2022 at 07:56:11PM +0200, LABBE Corentin wrote:
> > My problem is that a dma_sync on the data buffer corrupt the poison buffer as collateral dommage.
> > Probably because the sync operate on a larger region than the requested dma_sync length.
> > So I try to flush poison data in the cryptoAPI.
> 
> Data structures that are DMAed to must be aligned to
> the value returned by dma_get_cache_alignment(), as non-coherent DMA
> by definition can disturb the data inside that boundary.  That is not
> a bug but fundamentally part of how DMA works when the device attachment
> is not cache coherent.

I am sorry but I dont see how this can help my problem.