netdev - Re: [PATCH RFC leds + net-next 2/7] leds: trigger: netdev: simplify the driver by using bit field members

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Message-ID: <20201031004556.32c61a9d@kernel.org>
Date:   Sat, 31 Oct 2020 00:45:56 +0100
From:   Marek Behún <kabel@...nel.org>
To:     Jacek Anaszewski <jacek.anaszewski@...il.com>
Cc:     netdev@...r.kernel.org, linux-leds@...r.kernel.org,
        Pavel Machek <pavel@....cz>, Dan Murphy <dmurphy@...com>,
        Russell King <linux@...linux.org.uk>,
        Andrew Lunn <andrew@...n.ch>,
        Matthias Schiffer <matthias.schiffer@...tq-group.com>,
        "David S. Miller" <davem@...emloft.net>,
        Ben Whitten <ben.whitten@...il.com>
Subject: Re: [PATCH RFC leds + net-next 2/7] leds: trigger: netdev: simplify
 the driver by using bit field members

On Fri, 30 Oct 2020 23:37:52 +0100
Jacek Anaszewski <jacek.anaszewski@...il.com> wrote:

> Hi Marek,
> 
> Bitops are guaranteed to be atomic and this was done for a reason.

Hmm okay...
Sooo, netdev_trig_work cannot be executed at the same time as the
link/linkup/rx/tx changing stuff from netdev_trig_notify,
interval_store or netdev_led_attr_store, because all these functions
ensure cancelation of netdev_trig_work by calling
cancel_delayed_work_sync. Doesn't this somehow prevent the need for
memory barriers provided by atomic bitops?

BTW Jacek what do you think about the other patches?

Marek