On 7/7/20 2:39 PM, Jerome Brunet wrote:
On Tue 07 Jul 2020 at 21:23, Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote:
This is a much smaller set of cleanups, all related to warnings thrown
by the use of GENMASK() with an unsigned variable. I just made the
warning go away but I wonder if there's a better fix in the definition
of GENMASK() itself?
Looking at the patch I was going to ask the same thing.
It does not make much sense to me to force GENMASK arguments to be
integer (instead of unsigned integer) to then check there are positive ...
Agree, it's just that the following macro isn't exactly simple to change:
#define GENMASK_INPUT_CHECK(h, l) \
(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
__builtin_constant_p((l) > (h)), (l) > (h), 0)))
I couldn't find a means to avoid the comparison.
I just realized this is a fairly recent addition in 295bcca84916
('linux/bits.h: add compile time sanity check of GENMASK inputs'),
adding the author Rikard Falkeborn in CC:
include/linux/bits.h:26:28: warning: comparison of unsigned expression <
0 is always false [-Wtype-limits]
26 | __builtin_constant_p((l) > (h)), (l) > (h), 0)))
