From: Rodolfo Giometti <giometti@enneenne.com>
To: Charlie Johnston <charlie.johnston@ni.com>
Cc: linux-kernel@vger.kernel.org, brenda.streiff@ni.com
Subject: Re: [RFC PATCH] pps: Increase PPS_MAX_SOURCES value.
Date: Wed, 7 Jun 2023 09:33:27 +0200 [thread overview]
Message-ID: <fe435e68-8e05-9078-0fe6-63ef7cce2fc9@enneenne.com> (raw)
In-Reply-To: <20230605203147.694716-1-charlie.johnston@ni.com>
On 05/06/23 22:31, Charlie Johnston wrote:
> For consistency with what ptp uses for minors, this
> change sets PPS_MAX_SOURCES to MINORMASK + 1.
>
> The PPS_MAX_SOURCES value is currently set to 16. In
> some cases this was not sufficient for a system. For
> example, a system with multiple (4+) PCIe cards each
> with 4 PTP-capable ethernet interfaces could run out
> of the available PPS major:minors if each interface
> registers a PPS source.
>
> Signed-off-by: Charlie Johnston <charlie.johnston@ni.com>
> ---
> include/uapi/linux/pps.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/pps.h b/include/uapi/linux/pps.h
> index 009ebcd8ced5..85f472330da8 100644
> --- a/include/uapi/linux/pps.h
> +++ b/include/uapi/linux/pps.h
> @@ -26,7 +26,7 @@
> #include <linux/types.h>
>
> #define PPS_VERSION "5.3.6"
> -#define PPS_MAX_SOURCES 16 /* should be enough... */
> +#define PPS_MAX_SOURCES (MINORMASK + 1)
>
> /* Implementation note: the logical states ``assert'' and ``clear''
> * are implemented in terms of the chip register, i.e. ``assert''
I have just one question: are you sure that it's safe to call idr_alloc(..., 0,
(MINORMASK + 1), ...)?
Ciao,
Rodolfo
--
GNU/Linux Solutions e-mail: giometti@enneenne.com
Linux Device Driver giometti@linux.it
Embedded Systems phone: +39 349 2432127
UNIX programming skype: rodolfo.giometti
next prev parent reply other threads:[~2023-06-07 7:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-05 20:31 [RFC PATCH] pps: Increase PPS_MAX_SOURCES value Charlie Johnston
2023-06-07 7:33 ` Rodolfo Giometti [this message]
2023-06-07 22:07 ` Charlie Johnston
2023-06-09 7:30 ` Rodolfo Giometti
2023-06-09 21:00 ` Charlie Johnston
2023-06-12 16:07 ` Rodolfo Giometti
2023-06-20 20:42 ` Charlie Johnston
2023-06-21 15:31 ` Rodolfo Giometti
2023-06-23 2:03 ` Charlie Johnston
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