Re: remove the ->mapping_error method from dma_map_ops V2

[Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>]

On Thu, Nov 22, 2018 at 9:07 AM Russell King - ARM Linux
<linux@xxxxxxxxxxxxxxx> wrote:
>
> I'm afraid that won't work very well - 32 bit platforms with 64-bit
> addresses (LPAE) would have dma_addr_t as a 64-bit value, which
> wouldn't fit into an unsigned long.

Good point. So we'd have to have a special IS_DMA_ERR() function that
takes a dma_addr_t and checks the same "is it the top 4095 values".

Because I'd still prefer to allow people to return the _actual_ error,
and to have "return -Exyz" as the error case. That part still DTRT
even with dma_addr_t.

              Linus