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Date:   Wed, 11 Jan 2023 10:16:02 +0000
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Subject: Re: [PATCH V4 3/6] genirq/affinity: Don't pass irq_affinity_desc
 array to irq_build_affinity_masks
Content-Language: en-US
To:     Ming Lei <ming.lei@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jens Axboe <axboe@kernel.dk>
Cc:     linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>
References: <20221227022905.352674-1-ming.lei@redhat.com>
 <20221227022905.352674-4-ming.lei@redhat.com>
From:   John Garry <john.g.garry@oracle.com>
Organization: Oracle Corporation
In-Reply-To: <20221227022905.352674-4-ming.lei@redhat.com>
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On 27/12/2022 02:29, Ming Lei wrote:
> Prepare for abstracting irq_build_affinity_masks() into one public helper
> for assigning all CPUs evenly into several groups. Don't pass
> irq_affinity_desc array to irq_build_affinity_masks, instead return
> a cpumask array by storing each assigned group into one element of
> the array.
> 
> This way helps us to provide generic interface for grouping all CPUs
> evenly from NUMA and CPU locality viewpoint, and the cost is one extra
> allocation in irq_build_affinity_masks(), which should be fine since
> it is done via GFP_KERNEL and irq_build_affinity_masks() is called very
> less.
> 
> Reviewed-by: Christoph Hellwig<hch@lst.de>
> Signed-off-by: Ming Lei<ming.lei@redhat.com>

Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   kernel/irq/affinity.c | 34 ++++++++++++++++++++++++----------
>   1 file changed, 24 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index da6379cd27fd..00bba1020ecb 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -249,7 +249,7 @@ static int __irq_build_affinity_masks(unsigned int startvec,


>   
>    fail_npresmsk:
> @@ -393,7 +398,11 @@ static int irq_build_affinity_masks(unsigned int numvecs,
>   
>    fail_nmsk:
>   	free_cpumask_var(nmsk);
> -	return ret < 0 ? ret : 0;
> +	if (ret < 0) {
> +		kfree(masks);
> +		return NULL;

I dislike non-failure path passing through "fail" labels, but that is 
how the current code is...

> +	}
> +	return masks;
>   }
>