From: John Garry <john.garry@huawei.com>
To: kernel test robot <lkp@intel.com>,
"will@kernel.org" <will@kernel.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
<rikard.falkeborn@gmail.com>
Cc: "trivial@kernel.org" <trivial@kernel.org>,
"maz@kernel.org" <maz@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linuxarm <linuxarm@huawei.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"kbuild-all@lists.01.org" <kbuild-all@lists.01.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/4] iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist()
Date: Tue, 23 Jun 2020 10:21:12 +0100 [thread overview]
Message-ID: <5ba2e240-b324-d316-c00c-38c03ee49baa@huawei.com> (raw)
In-Reply-To: <202006230905.3HpPgtSC%lkp@intel.com>
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
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next prev parent reply other threads:[~2020-06-23 9:22 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-22 17:28 [PATCH 0/4] iommu/arm-smmu-v3: Improve cmdq lock efficiency John Garry
2020-06-22 17:28 ` [PATCH 1/4] iommu/arm-smmu-v3: Fix trivial typo John Garry
2020-06-22 17:28 ` [PATCH 2/4] iommu/arm-smmu-v3: Calculate bits for prod and owner John Garry
2020-06-22 17:28 ` [PATCH 3/4] iommu/arm-smmu-v3: Always issue a CMD_SYNC per batch John Garry
2020-06-22 17:28 ` [PATCH 4/4] iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist() John Garry
2020-06-23 1:07 ` kernel test robot
2020-06-23 9:21 ` John Garry [this message]
2020-06-23 9:35 ` Rikard Falkeborn
2020-06-23 10:19 ` John Garry
2020-06-23 13:55 ` Rikard Falkeborn
2020-06-26 10:05 ` John Garry
2020-06-23 16:22 ` Robin Murphy
2020-06-24 8:15 ` John Garry
2020-07-16 10:20 ` Will Deacon
2020-07-16 10:26 ` John Garry
2020-07-08 13:00 ` [PATCH 0/4] iommu/arm-smmu-v3: Improve cmdq lock efficiency John Garry
2020-07-16 10:19 ` Will Deacon
2020-07-16 10:22 ` Will Deacon
2020-07-16 10:28 ` Will Deacon
2020-07-16 10:56 ` John Garry
2020-07-16 11:22 ` Robin Murphy
2020-07-16 11:30 ` John Garry
2020-07-16 11:32 ` Will Deacon
2020-07-16 16:50 ` John Garry
2020-07-16 13:31 ` John Garry
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