Re: [stable] [PATCH] sbp2: fix check of return value of hpsb_allocate_and_register_addrspace

[Andrew Morton <akpm@osdl.org>]

On Sat, 03 Jun 2006 11:31:27 +0200
Andreas Schwab <schwab@suse.de> wrote:

> Michael Tokarev <mjt@tls.msk.ru> writes:
> 
> > Stefan Richter wrote:
> >> Chris Wright wrote:
> >>> * Stefan Richter (stefanr@s5r6.in-berlin.de) wrote:
> >> ....
> >>>> +++ linux-2.6.17-rc5/drivers/ieee1394/sbp2.c    2006-06-03
> >>>> 01:54:23.000000000 +0200
> >>>> @@ -845,7 +845,7 @@ static struct scsi_id_instance_data *sbp
> >>>>             &sbp2_highlevel, ud->ne->host, &sbp2_ops,
> >>>>             sizeof(struct sbp2_status_block), sizeof(quadlet_t),
> >>>>             0x010000000000ULL, CSR1212_ALL_SPACE_END);
> >>>> -    if (!scsi_id->status_fifo_addr) {
> >>>> +    if (scsi_id->status_fifo_addr == ~0ULL) {
> >
> > Umm.  Can this ~0ULL constant be #define'd to something?
> > It's way too simple to mis-read it as NULL (or ~NULL whatever).
> 
> How about writing it as -1?
> 

That's preferable.

It doesn't actually cause a problem, but status_fifo_addr is defined as
u64, which is not `unsigned long long'.  On powerpc, for example, u64 is
implemented as unsigned long.  -1 just works.