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SubjectRe: [PATCH v2 1/2] arm64: capabilities: Clarify argument passed to enable call back
On Wed, Jan 17, 2018 at 05:42:19PM +0000, Suzuki K Poulose wrote:
> We issue the enable() call back for all CPU hwcaps capabilities
> available on the system, on all the CPUs. So far we have ignored
> the argument passed to the call back, which had a prototype to
> accept a "void *" for use with on_each_cpu() and later with
> stop_machine(). However, with commit 0a0d111d40fd1
> ("arm64: cpufeature: Pass capability structure to ->enable callback"),
> there are some users of the argument who wants the matching capability
> struct pointer where there are multiple matching criteria for a single
> capability. Changing the prototype is quite an invasive change and
> will be part of a future series. For now, add a comment to clarify
> what is expected.
>
> Suggested-by: Dave Martin <dave.martin@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Andre Przywara <andre.przywara@arm.com>
> Cc: James Morse <james.morse@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arch/arm64/include/asm/cpufeature.h | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> index ac67cfc2585a..c049e28274d4 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -97,7 +97,14 @@ struct arm64_cpu_capabilities {
> u16 capability;
> int def_scope; /* default scope */
> bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
> - int (*enable)(void *); /* Called on all active CPUs */
> + /*
> + * For each @capability set in CPU hwcaps, @enable() is called on all
> + * active CPUs with const struct arm64_cpu_capabilities * as argument.

its argument.

> + * It is upto the callback (especially when multiple entries for the

s/upto/up to/

> + * same capability exists) to determine if any action should be taken

s/exists/exit/

> + * based on @matches() applies to thie CPU.

s/thie/this/
Still, the second half of the sentence doesn't really make a lot of
sense. Instead of:

"to determine if any action should be taken based on @matches() applies
to this CPU"

how about:

"to determine if any action should be taken based on the result of
@matches() for the local CPU."

Otherwise:

Acked-by: Will Deacon <will.deacon@arm.com>

Will

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