Re: [PATCH][RFC] asm-generic:remove calling flush_write_buffers()in dma_sync_*_for_cpu

From: Alan Cox
Date: Mon Jun 29 2009 - 12:31:01 EST


> Wouldn't it be better to put the flush_write_buffer in the specific
> operation (swiotlb_sync_*_for_*) rather than the multiplexer?
>
> Maybe in that case, smp_wmb() would be more appropriate because
> it is defined on all architectures.

smp_wmb() is stronger and it would slow down x86 if we did that (we'd go
from no-op on a coherent platform to using mfence/lfence etc)

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