Messages in this thread | | | From | Nick Desaulniers <> | Date | Thu, 24 Oct 2019 14:46:10 -0700 | Subject | Re: [PATCH] dm raid: Remove unnecessary negation of a shift in raid10_format_to_md_layout |
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On Thu, Oct 24, 2019 at 1:28 PM Nathan Chancellor <natechancellor@gmail.com> wrote: > > When building with Clang + -Wtautological-constant-compare: > > drivers/md/dm-raid.c:619:8: warning: converting the result of '<<' to a > boolean always evaluates to true [-Wtautological-constant-compare] > r = !RAID10_OFFSET; > ^ > drivers/md/dm-raid.c:517:28: note: expanded from macro 'RAID10_OFFSET' > #define RAID10_OFFSET (1 << 16) /* stripes with data > copies area adjacent on devices */ > ^ > 1 warning generated. > > Negating a non-zero number will always make it zero, which is the > default value of r in this function so this statement is unnecessary;
Yep, thanks for the patch. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> (algorithm should be an enum, and there's some code duplication between ALGORITHM_RAID10_OFFSET and ALGORITHM_RAID10_FAR cases, but this patch is good enough).
> remove it so that clang no longer warns. > > Link: https://github.com/ClangBuiltLinux/linux/issues/753 > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> > --- > drivers/md/dm-raid.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c > index b0aa595e4375..13fabc6779e5 100644 > --- a/drivers/md/dm-raid.c > +++ b/drivers/md/dm-raid.c > @@ -616,7 +616,6 @@ static int raid10_format_to_md_layout(struct raid_set *rs, > > } else if (algorithm == ALGORITHM_RAID10_FAR) { > f = copies; > - r = !RAID10_OFFSET; > if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) > r |= RAID10_USE_FAR_SETS; >
-- Thanks, ~Nick Desaulniers
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