linux-kernel - Re: [PATCH v7 5/7] perf/amd/iommu: Clean up perf_iommu_enable

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Date:   Thu, 12 Jan 2017 15:14:57 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Cc:     linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
        joro@...tes.org, peterz@...radead.org, mingo@...hat.com
Subject: Re: [PATCH v7 5/7] perf/amd/iommu: Clean up perf_iommu_enable_event

On Mon, Jan 09, 2017 at 09:33:45PM -0600, Suravee Suthikulpanit wrote:
> This patch cleans up:
>   * Various bitwise operations in perf_iommu_enable_event
>   * Make use macros BIT(x)
> 
> This should not affect logic and functionality.
> 
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Borislav Petkov <bp@...en8.de>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> ---
>  arch/x86/events/amd/iommu.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/events/amd/iommu.c b/arch/x86/events/amd/iommu.c
> index 9bff41d..2403c78 100644
> --- a/arch/x86/events/amd/iommu.c
> +++ b/arch/x86/events/amd/iommu.c
> @@ -258,21 +258,21 @@ static void perf_iommu_enable_event(struct perf_event *ev)
>  	amd_iommu_pc_set_reg(0, devid, bank, cntr,
>  			     IOMMU_PC_COUNTER_SRC_REG, &reg);
>  
> -	reg = 0ULL | devid | (_GET_DEVID_MASK(ev) << 32);
> +	reg = devid | (_GET_DEVID_MASK(ev) << 32);
>  	if (reg)
> -		reg |= (1UL << 31);
> +		reg |= BIT(31);
>  	amd_iommu_pc_set_reg(0, devid, bank, cntr,
>  			     IOMMU_PC_DEVID_MATCH_REG, &reg);
>  
> -	reg = 0ULL | _GET_PASID(ev) | (_GET_PASID_MASK(ev) << 32);
> +	reg = _GET_PASID(ev) | (_GET_PASID_MASK(ev) << 32);
>  	if (reg)
> -		reg |= (1UL << 31);
> +		reg |= BIT(31);
>  	amd_iommu_pc_set_reg(0, devid, bank, cntr,
>  			     IOMMU_PC_PASID_MATCH_REG, &reg);
>  
> -	reg = 0ULL | _GET_DOMID(ev) | (_GET_DOMID_MASK(ev) << 32);
> +	reg = _GET_DOMID(ev) | (_GET_DOMID_MASK(ev) << 32);
>  	if (reg)
> -		reg |= (1UL << 31);
> +		reg |= BIT(31);
>  	amd_iommu_pc_set_reg(0, devid, bank, cntr,
>  			     IOMMU_PC_DOMID_MATCH_REG, &reg);
>  }
> -- 

Ah ok, you're doing it here, good.

For the next version of the patchset, please reorder all cleanups first
and then the patches adding functional changes/new features.

Thanks.

-- 
Regards/Gruss,
    Boris.

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