From: Vinicius Costa Gomes <vinicius.gomes@intel•com>
To: Richard Cochran <richardcochran@gmail•com>
Cc: Xabier Marquiegui <xabier.marquiegui@gmail•com>,
alex.maftei@amd•com, chrony-dev@chrony•tuxfamily.org,
davem@davemloft•net, horms@kernel•org, mlichvar@redhat•com,
netdev@vger•kernel.org, ntp-lists@mattcorallo•com,
reibax@gmail•com, rrameshbabu@nvidia•com, shuah@kernel•org
Subject: Re: [PATCH net-next v2 2/3] ptp: support multiple timestamp event readers
Date: Thu, 14 Sep 2023 10:12:54 -0700 [thread overview]
Message-ID: <87jzssel0p.fsf@intel.com> (raw)
In-Reply-To: <ZQMiKE6x/euOv3Hc@hoboy.vegasvil.org>
Hi Richard,
Richard Cochran <richardcochran@gmail•com> writes:
> On Wed, Sep 13, 2023 at 02:25:48PM -0700, Vinicius Costa Gomes wrote:
>
>> Taking a quick look, it seems that you would have to change 'struct
>> posix_clock_file_operations' to also pass around the 'struct file' of
>> the file being used.
>
> And let drivers compare struct file pointers from different consumers?
>
That was the first idea, not very good I admit.
What you said below sounds better, more "final product".
>> That way we can track each user/"open()". And if one program decides
>> that it needs to have have multiple fds with different masks, and so
>> different queues, it should just work.
>>
>> What do you think?
>
> See posix-clock.c : posix_clock_open()
>
> When the file is opened, the fp->private_data is used to track the
> posix_clock that was registered as a character device by the ptp
> clock instance.
>
> That character device may be opened multiple times, each time there is
> a unique fp, but fp->private_data points to the same ptp clock instance.
>
> So the information of which fp is being read() is lost.
yeah, that's the core issue.
>
> Looks like you will have to re-work posix-clock.c to allow drivers to
> provide their own "private" data populated during posix_clock_operations::open()
>
> Needs thought...
>
Cheers,
--
Vinicius
next prev parent reply other threads:[~2023-09-14 17:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 22:02 [PATCH net-next v2 1/3] ptp: Replace timestamp event queue with linked list Xabier Marquiegui
2023-09-12 22:02 ` [PATCH net-next v2 2/3] ptp: support multiple timestamp event readers Xabier Marquiegui
2023-09-13 0:10 ` Vinicius Costa Gomes
2023-09-13 8:57 ` Xabier Marquiegui
2023-09-13 21:25 ` Vinicius Costa Gomes
2023-09-14 10:02 ` Xabier Marquiegui
2023-09-14 15:09 ` Richard Cochran
2023-09-14 17:12 ` Vinicius Costa Gomes [this message]
2023-09-19 15:15 ` kernel test robot
2023-09-12 22:02 ` [PATCH net-next v2 3/3] ptp: support event queue reader channel masks Xabier Marquiegui
2023-09-13 0:05 ` [PATCH net-next v2 1/3] ptp: Replace timestamp event queue with linked list Vinicius Costa Gomes
2023-09-13 7:56 ` Jiri Pirko
2023-09-14 14:21 ` Richard Cochran
2023-09-20 15:40 ` kernel test robot
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