| Message ID | 20190726112821.19775-1-anders.roxell@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | iommu: arm-smmu-v3: Mark expected switch fall-through | expand |
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 */ > } >
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(); + break; default: BUG(); /* STE corruption */ }
When fall-through warnings was enabled by default, commit d93512ef0f0e ("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") Signed-off-by: Anders Roxell <anders.roxell@linaro.org> --- drivers/iommu/arm-smmu-v3.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) -- 2.20.1