On Fri, Aug 09, 2019 at 09:49:10PM -0700, Nathan Chancellor wrote:
> clang warns four times:
>
> drivers/firmware/arm_scmi/perf.c:320:24: warning: variable 'db' is
> uninitialized when used within its own initialization [-Wuninitialized]
> SCMI_PERF_FC_RING_DB(db, 64);
> ~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> drivers/firmware/arm_scmi/perf.c:300:31: note: expanded from macro
> 'SCMI_PERF_FC_RING_DB'
> struct scmi_fc_db_info *db = doorbell; \
> ~~ ^~~~~~~~
>
> This happens because the doorbell identifier becomes db after
> preprocessing:
>
> if (db->width == 1)
> do {
> u8 val = 0;
> struct scmi_fc_db_info *db = db;
> if (db->mask)
> val = ioread8(db->addr) & db->mask;
> iowrite8((u8)db->set | val, db->addr);
> } while (0);
>
> We could swap the doorbell and db identifiers within the macro and that
> would resolve the issue; however, there doesn't appear to be a good
> reason for having two copies of the same variable. Eliminate the one in
> the do while loop to prevent this warning and make the code clearer.
>
I originally had exactly what we will after this patch applied. I think
one of the tool complained about argument 'db' reused in the macro
might have possible side-effects. That's the reason I moved it. I will
dig it up and fold this in the original patch as before.
--
Regards,
Sudeep
