linux-kernel - Re: [PATCH 3/3] iova: Correct comment for free_cpu_cached

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Message-ID: <cb4547e8-bab4-bea5-e9c2-18884e3e5e12@huawei.com>
Date:   Tue, 23 Mar 2021 13:56:58 +0000
From:   John Garry <john.garry@...wei.com>
To:     Robin Murphy <robin.murphy@....com>, <dwmw2@...radead.org>,
        <baolu.lu@...ux.intel.com>, <joro@...tes.org>, <will@...nel.org>
CC:     <iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
        <linuxarm@...wei.com>
Subject: Re: [PATCH 3/3] iova: Correct comment for free_cpu_cached_iovas()

On 23/03/2021 13:05, Robin Murphy wrote:
> On 2021-03-01 12:12, John Garry wrote:
>> Function free_cpu_cached_iovas() is not only called when a CPU is
>> hotplugged, so remove that part of the code comment.
> 
> FWIW I read it as clarifying why this is broken out into a separate 
> function vs. a monolithic "free all cached IOVAs" routine that handles 
> both the per-cpu and global caches 

> it never said "*only* used..."

It seems to be implying that.

It's only a code comment, so I don't care too much either way and can 
drop this change.

> 
> As such I'd hesitate to call it incorrect, but it's certainly arguable 
> whether it needs to be stated or not, especially once the hotplug 
> callsite is now obvious in the same file - on which note the function 
> itself also shouldn't need to be public any more, no?
> 

Right, I actually missed deleting iommu_dma_free_cpu_cached_iovas(), so 
can fix that now.

Cheers,
John

> Robin.
> 
>> Signed-off-by: John Garry <john.garry@...wei.com>
>> ---
>>   drivers/iommu/iova.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
>> index c78312560425..465b3b0eeeb0 100644
>> --- a/drivers/iommu/iova.c
>> +++ b/drivers/iommu/iova.c
>> @@ -996,7 +996,7 @@ static void free_iova_rcaches(struct iova_domain 
>> *iovad)
>>   }
>>   /*
>> - * free all the IOVA ranges cached by a cpu (used when cpu is unplugged)
>> + * free all the IOVA ranges cached by a cpu
>>    */
>>   void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
>>   {
>>
> .