On Wed, Apr 24, 2019 at 11:49:37AM -0700, Nick Desaulniers wrote:
> On Wed, Apr 24, 2019 at 11:34 AM Nathan Chancellor
> <[email protected]> wrote:
> >
> > Clang warns:
> >
> > drivers/thunderbolt/tunnel.c:504:17: warning: implicit truncation from
> > 'int' to bit-field changes value from 5 to -3
> > [-Wbitfield-constant-conversion]
> > path->priority = 5;
> > ^ ~
> > 1 warning generated.
> >
> > The priority member in struct tb_path is only ever assigned a positive
> > number:
> >
> > $ rg -n priority drivers/thunderbolt/path.c
> > drivers/thunderbolt/tunnel.c:99: path->priority = 3;
> > drivers/thunderbolt/tunnel.c:308: path->priority = 2;
> > drivers/thunderbolt/tunnel.c:323: path->priority = 1;
> > drivers/thunderbolt/tunnel.c:504: path->priority = 5;
>
> LGTM. Looks like drivers/thunderbolt/tb_regs.h also defines it as u32
> (no change needed here).
> Triple checking it's uses, looks like it gets assigned:
> drivers/thunderbolt/path.c#L492:
> hop.priority = path->priority;
> hop is an instance of a struct tb_regs_hop, which is the definition I
> was looking at above. LGTM thanks Nathan!
> Reviewed-by: Nick Desaulniers <[email protected]>
Thanks for the review!
>
> >
> > Furthmore, that value is only assigned to an unsigned integer in
Although apparently I can't spell... should be "Furthermore".
> > tb_path_activate (the priority member in struct tb_regs_hop).
> >
> > Fixes: 44242d6c9703 ("thunderbolt: Add support for DMA tunnels")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/454
> > Signed-off-by: Nathan Chancellor <[email protected]>
> > ---
> > drivers/thunderbolt/tb.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
> > index 15d225dcb403..b12c8f33d89c 100644
> > --- a/drivers/thunderbolt/tb.h
> > +++ b/drivers/thunderbolt/tb.h
> > @@ -225,7 +225,7 @@ struct tb_path {
> > enum tb_path_port ingress_fc_enable;
> > enum tb_path_port egress_fc_enable;
> >
> > - int priority:3;
> > + unsigned int priority:3;
> > int weight:4;
> > bool drop_packages;
> > bool activated;
> > --
> > 2.21.0
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers
