On Fri, Apr 15, 2016 at 12:05:26PM -0700, James Bottomley wrote:
> On Fri, 2016-04-15 at 20:56 +0200, Denys Vlasenko wrote:
> > and now *many* users of qla2x00 and new-ish gcc are going to
> > very much notice it, as their kernels will start crashing reliably.
> >
> > The commits can be reverted, sure, but they per se do not contain
> > anything unusual. They, together with not very typical construct
> > in qla2x00_get_host_fabric_name, one
> > which boils down to "swab64p(constant_array_of_8_bytes)",
> > just happen to nudge gcc in a right way to finally trigger the bug.
> >
> > So I came with another idea how to forestall the imminent deluge of
> > qla2x00 oops reports - this patch.
>
> There are actually a raft of checkers that run the upstream code which
> aren't seeing any problem; likely because the code is harder to trigger
> than you think. So, lets wait until the resolution of the other thread
> before we panic, especially since we're only at -rc3.
Regardless of the outcome of the gcc bug, it seems kind of silly to
byteswap a constant value of 0xffffffffffffffff.
uint8_t node_name[WWN_SIZE] = { 0xFF, 0xFF, 0xFF, 0xFF, \
0xFF, 0xFF, 0xFF, 0xFF};
u64 fabric_name = wwn_to_u64(node_name);
Similar to what Denys suggested, it can just be:
u64 fabric_name = -1;
or
u64 fabric_name = 0xffffffffffffffff;
Wouldn't that be an improvement to the code regardless?
--
Josh
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