Messages in this thread | | | Subject | Re: [PATCH] iommu: arm-smmu-v3: Mark expected switch fall-through | From | Robin Murphy <> | Date | Fri, 26 Jul 2019 13:01:02 +0100 |
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On 26/07/2019 12:28, Anders Roxell wrote: > When fall-through warnings was enabled by default, commit d93512ef0f0e
That commit ID only exists in a handful of old linux-next tags.
> ("Makefile: Globally enable fall-through warning"), the following > warning was starting to show up: > > ../drivers/iommu/arm-smmu-v3.c: In function ‘arm_smmu_write_strtab_ent’: > ../drivers/iommu/arm-smmu-v3.c:1189:7: warning: this statement may fall > through [-Wimplicit-fallthrough=] > if (disable_bypass) > ^ > ../drivers/iommu/arm-smmu-v3.c:1191:3: note: here > default: > ^~~~~~~ > > Rework so that the compiler doesn't warn about fall-through. Make it > clearer by calling 'BUG()' when disable_bypass is set, and always > 'break;' > > Cc: stable@vger.kernel.org # v4.2+ > Fixes: 5bc0a11664e1 ("iommu/arm-smmu: Don't BUG() if we find aborting STEs with disable_bypass")
Why? There's no actual bug, and not even current kernels have that warning enabled.
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> > --- > drivers/iommu/arm-smmu-v3.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index a9a9fabd3968..8e5f0565996d 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -1186,8 +1186,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, > ste_live = true; > break; > case STRTAB_STE_0_CFG_ABORT: > - if (disable_bypass) > - break; > + if (!disable_bypass) > + BUG();
You may as well just use BUG_ON().
Robin.
> + break; > default: > BUG(); /* STE corruption */ > } >
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