[openib-general] Reserved L_Key API

[Michael S. Tsirkin]

Hello!
Quoting r. Roland Dreier (roland at topspin.com) "Re: [openib-general] Reserved L_Key API":
>     Dror> Think of Tavor as a software friendly design. Use: start
>     Dror> address = 0x0000000000000001 length = 0xffffffffffffffff pa
>     Dror> = 1 And then you got all memory space mapped + protection
>     Dror> violation if you try to access a NULL pointer :)
> 
> That's cute :) But I think 0x0 is more likely to be a valid DMA
> address than 0xffffffffffffffff (I seem to remember this coming up
> when pci_dma_mapping_error() was added to the kernel).
> 
>  - R.

In this case, you could cover all space with two (overlapping) keys, and add a
function to map address/size pair to the correct key.