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Subject: Re: [PATCH v2] mm: cma: support sysfs
To:     Minchan Kim <minchan@kernel.org>
CC:     Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        <gregkh@linuxfoundation.org>, <surenb@google.com>,
        <joaodias@google.com>, <willy@infradead.org>
References: <20210208180142.2765456-1-minchan@kernel.org>
 <e01c111b-fb20-0586-c7a9-dd6d922c0e57@nvidia.com>
 <YCHLAdabGmm7kqSH@google.com>
From:   John Hubbard <jhubbard@nvidia.com>
Message-ID: <43cd6fc4-5bc5-50ec-0252-ffe09afd68ea@nvidia.com>
Date:   Mon, 8 Feb 2021 17:57:17 -0800
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On 2/8/21 3:36 PM, Minchan Kim wrote:
...
>>>    	char name[CMA_MAX_NAME];
>>> +#ifdef CONFIG_CMA_SYSFS
>>> +	struct cma_stat	*stat;
>>
>> This should not be a pointer. By making it a pointer, you've added a bunch of pointless
>> extra code to the implementation.
> 
> Originally, I went with the object lifetime with struct cma as you
> suggested to make code simple. However, Greg KH wanted to have
> release for kobj_type since it is consistent with other kboject
> handling.

Are you talking about the kobj in your new struct cma_stat? That seems
like circular logic if so. I'm guessing Greg just wanted kobj methods
to be used *if* you are dealing with kobjects. That's a narrower point.

I can't imagine that he would have insisted on having additional
allocations just so that kobj freeing methods could be used. :)


thanks,
-- 
John Hubbard
NVIDIA