Messages in this thread | | | Date | Fri, 11 Aug 2023 11:19:25 +0100 | From | Will Deacon <> | Subject | Re: [PATCH V4 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device() |
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On Wed, Aug 09, 2023 at 01:54:55PM +0100, Suzuki K Poulose wrote: > On 08/08/2023 14:16, Will Deacon wrote: > > On Tue, Aug 08, 2023 at 09:48:16AM +0100, Suzuki K Poulose wrote: > > > On 08/08/2023 09:22, Anshuman Khandual wrote: > > > > Sanity checking all the GICC tables for same interrupt number, and ensuring > > > > a homogeneous ACPI based machine, could be used for other platform devices > > > > as well. Hence this refactors arm_spe_acpi_register_device() into a common > > > > helper arm_acpi_register_pmu_device(). > > > > > > > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > > > Cc: Will Deacon <will@kernel.org> > > > > Cc: Mark Rutland <mark.rutland@arm.com> > > > > Cc: linux-arm-kernel@lists.infradead.org > > > > Cc: linux-kernel@vger.kernel.org > > > > Co-developed-by: Will Deacon <will@kernel.org> > > > > Signed-off-by: Will Deacon <will@kernel.org> > > > > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > > > > --- > > > > drivers/perf/arm_pmu_acpi.c | 105 ++++++++++++++++++++++-------------- > > > > 1 file changed, 65 insertions(+), 40 deletions(-) > > > > > > > > diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c > > > > index 90815ad762eb..72454bef2a70 100644 > > > > --- a/drivers/perf/arm_pmu_acpi.c > > > > +++ b/drivers/perf/arm_pmu_acpi.c > > > > + pdev->resource[0].start = irq; > > > > + ret = platform_device_register(pdev); > > > > + if (ret < 0) { > > > > + pr_warn("ACPI: %s: Unable to register device\n", pdev->name); > > > > + acpi_unregister_gsi(gsi); > > > > + } > > > > + return ret; > > > > > > A postivie return value here could confuse the caller. Also, with my comment > > > below, we don't really need to return something from here. > > > > How does this return a positive value? > > Right now, there aren't. My point is this function returns a "return value" > of another function. And the caller of this function doesn't > really follow the "check" it needs. e.g.: > > ret = foo(); > if (ret < 0) > error; > return ret; > > > > And the caller only checks for > > if (ret) > error; > > This seems fragile.
Yeah, the '< 0' check is weird. I'd be inclined to drop that entirely from the helper function tbh...
> > > > + int ret = arm_acpi_register_pmu_device(&spe_dev, ACPI_MADT_GICC_SPE, > > > > + arm_spe_parse_gsi); > > > > + if (ret) > > > > pr_warn("ACPI: SPE: Unable to register device\n"); > > > > > > With this change, a system without SPE interrupt description always > > > generates the above message. Is this intended ? > > > > If there are no irqs, why doesn't this return 0? > > Apologies, I missed that. > > > arm_acpi_register_pmu_device() should only fail if either: > > > > - The static resources passed in are broken > > - The tables are not homogeneous > > - We fail to register the interrupt > > > > so something is amiss. > > Agreed. We don't need duplicate messages about an error ? > i.e., one in arm_acpi_register_pmu_device() and another > one in the caller ? (Of course adding any missing error msgs).
... and then just print the registration failure message in the caller.
Will
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