Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH v3 2/4] drm/i915/pmu: Use kstat_irqs to get interrupt count | Date | Sun, 06 Dec 2020 22:33:09 +0100 |
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On Sun, Dec 06 2020 at 17:38, Thomas Gleixner wrote: > On Fri, Dec 04 2020 at 18:43, Jerry Snitselaar wrote: >> Now that kstat_irqs is exported, get rid of count_interrupts in >> i915_pmu.c > > May I ask why this has been merged in the first place? > > Nothing in a driver has ever to fiddle with the internals of an irq > descriptor. We have functions for properly accessing them. Just because > C allows to fiddle with everything is not a justification. If the > required function is not exported then adding the export with a proper > explanation is not asked too much. > > Also this lacks protection or at least a comment why this can be called > safely and is not subject to a concurrent removal of the irq descriptor. > The same problem exists when calling kstat_irqs(). It's even documented > at the top of the function.
And as pointed out vs. that TPM thing this really could have been a trivial
i915->irqs++;
in the interrupt handler and a read of that instead of iterating over all possible cpus and summing it up. Oh well...
Thanks,
tglx
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