Andrew Morton writes:

Matt Porter [off-list ref] wrote:

quoted

+static u64 dma_mask = 0xffffffffULL;

I'm sure you're totally uninterested in this, but the above will probably
generate warnings on (say) ppc64, where u64 is implemented as unsigned
long.

I usually chuck a simple `-1' in there and the compiler always gets it
right, regardless of signedness and size and architecture.

Umm, I think we actually want 2^32-1 not -1, don't we?  In which case
I think Matt's code is what we have to have.

I tried a little test compile with gcc 4.0 with -m64 -Wall and it
didn't generate a warning with the 0xffffffffULL constant.

Paul.