2014/1/16 Konrad Rzeszutek Wilk <[email protected]>: > On Tue, Jan 14, 2014 at 11:13:46PM +0900, Akinobu Mita wrote: >> Calling dma_alloc_coherent() with __GFP_ZERO must return zeroed memory. >> >> But when the contiguous memory allocator (CMA) is enabled on x86 and >> the memory region is allocated by dma_alloc_from_contiguous(), it >> doesn't return zeroed memory. Because dma_generic_alloc_coherent() > > So why not fix it there to return zeroed out memory?
I thought it looked nicer than this patch as we can remove memset from all caller of dma_alloc_from_contiguous(). But if I look at the caller on arm, we can't simply remove the memset because __dma_clear_buffer() is used there for ensuring cache flushing and it is used in many places. Of course we can do redundant memset in dma_alloc_from_contiguous(), but now I think this patch is less impact for fixing this problem. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
