Re: With Daniel Phillips Patch

Justin T. Gibbs
2001-08-23T00:02:05Z

>Consider network drivers (most PCI ones) that keep track of:
>
> struct sk_buff *skb;
> dma_addr_t mapping;
>
>pairs for each transmit packet. With your suggested change,
>their structures will increase 32-bits in size for each entry
>when CONFIG_HIGHMEM on x86 or on a 64-bit platform.

They already increase by 32bits on IA64. A driver should use a
fixed sized type for a fixed sized address that corresponds to its
capabilities. There is no guarantee of the size of dma_addr_t.
It is opaque and should be able to represent all dma (or I would prefer
bus) addresses in the system. The examples I've seen where people
assume it to be 32bits in size are, well, broken.

--
Justin