Re: [PATCH] ARM:mm: fix kmap_atomic_to_page

[Arnd Bergmann]

On Monday 12 October 2015 14:30:39 Jongsung Kim wrote:
> We tried to utilize a HW compressor as a zram backend. Current zram uses
> kmap_atomic to map a page, and the HW DMAes. So we needed to use
> kmap_atomic_to_page to get the page to be dma-mapped.

How about changing the zcomp code to pass the page pointer instead of
the kernel space pointer? That would avoid having to do the kmap_atomic,
which can itself be expensive on 32-bit machines and should not
be needed here if you have a HW DMA engine doing the compression.

	Arnd
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