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From: John Hubbard <jhubbard@nvidia.com>
To: "Ahmed S. Darwish" <a.darwish@linutronix.de>,
	Jason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>, <linux-kernel@vger.kernel.org>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Christoph Hellwig <hch@lst.de>, "Hugh Dickins" <hughd@google.com>,
	Jan Kara <jack@suse.cz>, Jann Horn <jannh@google.com>,
	Kirill Shutemov <kirill@shutemov.name>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	Leon Romanovsky <leonro@nvidia.com>,
	Linux-MM <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH v2 2/2] mm: prevent gup_fast from racing with COW during fork
Date: Mon, 2 Nov 2020 18:20:45 -0800	[thread overview]
Message-ID: <e03dba4e-fd1d-a32c-c99c-fc3fa51419c4@nvidia.com> (raw)
In-Reply-To: <20201103004133.GD52235@lx-t490>

On 11/2/20 4:41 PM, Ahmed S. Darwish wrote:
> On Mon, Nov 02, 2020 at 08:25:32PM -0400, Jason Gunthorpe wrote:
>> On Tue, Nov 03, 2020 at 01:17:12AM +0100, Ahmed S. Darwish wrote:
>>
>>> Please stick with the official exported API: raw_write_seqcount_begin().
>>
>> How did you know this was 'offical exported API' ??
>>
> 
> All the official exported seqlock.h APIs are marked with verbose
> kernel-doc annotations on top. The rest are internal...
> 

OK, but no one here was able to deduce that, probably because there is not
enough consistency throughout the kernel to be able to assume such things--even
though your seqlock project is internally consistent. It's just not *quite*
enough communication.

I think if we added the following it would be very nice:

a) Short comments to the "unofficial and internal" routines, identifying them as
such, and

b) Short comments to the "official API for general use", also identifying
those as such.

c) A comment about what makes "raw" actually raw, for seqlock.


Since I'm proposing new work, I'll also offer to help, perhaps by putting together
a small patch to get it kicked off, if you approve of the idea.

thanks,
-- 
John Hubbard
NVIDIA


  reply	other threads:[~2020-11-03  2:20 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-30 14:46 [PATCH v2 0/2] Add a seqcount between gup_fast and copy_page_range() Jason Gunthorpe
2020-10-30 14:46 ` [PATCH v2 1/2] mm: reorganize internal_get_user_pages_fast() Jason Gunthorpe
2020-10-30 16:29   ` Jan Kara
2020-10-30 21:31   ` John Hubbard
2020-10-30 22:36   ` Peter Xu
2020-10-30 14:46 ` [PATCH v2 2/2] mm: prevent gup_fast from racing with COW during fork Jason Gunthorpe
2020-10-30 16:51   ` Jan Kara
2020-10-30 17:02     ` Jason Gunthorpe
2020-11-02  8:31       ` Jan Kara
2020-10-30 21:20   ` John Hubbard
2020-10-30 22:52   ` Peter Xu
2020-10-30 23:51     ` Jason Gunthorpe
2020-10-31 15:26       ` Peter Xu
2020-11-03  0:33         ` Ahmed S. Darwish
2020-11-03  0:17       ` Ahmed S. Darwish
2020-11-03  0:25         ` Jason Gunthorpe
2020-11-03  0:41           ` Ahmed S. Darwish
2020-11-03  2:20             ` John Hubbard [this message]
2020-11-03  6:52               ` Ahmed S. Darwish
2020-11-03  7:05                 ` John Hubbard
2020-11-03 17:40                 ` Linus Torvalds
2020-11-04  1:32                   ` Ahmed S. Darwish
2020-11-04  2:01                     ` John Hubbard
2020-11-04  3:17                       ` Ahmed S. Darwish
2020-11-04 18:38                         ` Linus Torvalds
2020-11-10 11:53                         ` Peter Zijlstra
2020-11-03 17:03         ` Peter Xu
2020-11-02 23:58   ` Ahmed S. Darwish
2020-11-02 22:19 ` [PATCH v2 0/2] Add a seqcount between gup_fast and copy_page_range() Ahmed S. Darwish
2020-11-02 22:39   ` Linus Torvalds
2020-11-02 23:18     ` Ahmed S. Darwish

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