Re: minimum guaranteed alignment of dma_alloc_coherent?

Dan Malek wrote:

quoted

On a side note, do I really need to pass GFP_DMA ....

The GFP_DMA is architecture dependent.  Are you writing
a driver to be used across multiple architectures?

It's conceivable that the driver could work on PowerPC and ARM.

If it's
necessary, I'd document why you are using it (an ISA device
on x86 for example) and then let other architectures
determine if it's necessary for them.

I guess I'm not clear.  I was wondering why an API called "dma_alloc_cohere=
nt" (that has the word "dma" in it) needs to be told to allocate DMA-safe m=
emory.  When would it make sense to call dma_alloc_cohernet without GFP_DMA=
?  If you don't want DMA-able memory, then you shouldn't be calling dma_all=
oc_anything.

--=20
Timur Tabi
Linux kernel developer=