Messages in this thread | | | Subject | Re: [PATCH 4/4] iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist() | From | John Garry <> | Date | Tue, 23 Jun 2020 10:21:12 +0100 |
| |
On 23/06/2020 02:07, kernel test robot wrote:
+ Rikard, as the GENMASK compile-time sanity checks were added recently
> Hi John, > > I love your patch! Perhaps something to improve: > > [auto build test WARNING on iommu/next] > [If your patch is applied to the wrong git tree, kindly drop us a note. > And when submitting patch, we suggest to use as documented in > https://git-scm.com/docs/git-format-patch] > > url: https://github.com/0day-ci/linux/commits/John-Garry/iommu-arm-smmu-v3-Improve-cmdq-lock-efficiency/20200623-013438 > base: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next > config: arm64-randconfig-c024-20200622 (attached as .config) > compiler: aarch64-linux-gcc (GCC) 9.3.0 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@intel.com> > > All warnings (new ones prefixed by >>, old ones prefixed by <<): > > In file included from include/linux/bits.h:23, > from include/linux/ioport.h:15, > from include/linux/acpi.h:12, > from drivers/iommu/arm-smmu-v3.c:12: > drivers/iommu/arm-smmu-v3.c: In function 'arm_smmu_cmdq_issue_cmdlist': > 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)))
I'd say that GENMASK_INPUT_CHECK() should be able to handle a l=0 and h=unsigned value, so I doubt this warn.
Using GENMASK((int)cmdq->q.llq.max_n_shift, 0) resolves it, but it looks like GENMASK_INPUT_CHECK() could be improved.
> | ^ > include/linux/build_bug.h:16:62: note: in definition of macro 'BUILD_BUG_ON_ZERO' > 16 | #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) > | ^ > include/linux/bits.h:39:3: note: in expansion of macro 'GENMASK_INPUT_CHECK' > 39 | (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l)) > | ^~~~~~~~~~~~~~~~~~~ >>> drivers/iommu/arm-smmu-v3.c:1404:18: note: in expansion of macro 'GENMASK' > 1404 | u32 prod_mask = GENMASK(cmdq->q.llq.max_n_shift, 0); > | ^~~~~~~ > include/linux/bits.h:26:40: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] > 26 | __builtin_constant_p((l) > (h)), (l) > (h), 0))) > | ^ > include/linux/build_bug.h:16:62: note: in definition of macro 'BUILD_BUG_ON_ZERO' > 16 | #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) > | ^ > include/linux/bits.h:39:3: note: in expansion of macro 'GENMASK_INPUT_CHECK' > 39 | (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l)) > | ^~~~~~~~~~~~~~~~~~~ >>> drivers/iommu/arm-smmu-v3.c:1404:18: note: in expansion of macro 'GENMASK' > 1404 | u32 prod_mask = GENMASK(cmdq->q.llq.max_n_shift, 0); > | ^~~~~~~ > > vim +/GENMASK +1404 drivers/iommu/arm-smmu-v3.c
| |