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From: Vladimir Oltean <olteanv@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, yangbo.lu@nxp.com,
	xiaoliang.yang_1@nxp.com, UNGLinuxDriver@microchip.com,
	claudiu.manoil@nxp.com, alexandre.belloni@bootlin.com,
	andrew@lunn.ch, vivien.didelot@gmail.com, f.fainelli@gmail.com,
	kuba@kernel.org
Subject: Re: [PATCH net 2/7] net: mscc: ocelot: add locking for the port TX timestamp ID
Date: Fri, 18 Sep 2020 02:43:40 +0300	[thread overview]
Message-ID: <20200917234322.qqwxyq6k33qm6bca@skbuf> (raw)
In-Reply-To: <20200916.171926.383551951466329210.davem@davemloft.net>

On Wed, Sep 16, 2020 at 05:19:26PM -0700, David Miller wrote:
> From: Vladimir Oltean <olteanv@gmail.com>
> Date: Tue, 15 Sep 2020 21:22:24 +0300
>
> > This is a problem because, at least theoretically, another timestampable
> > skb might use the same ocelot_port->ts_id before that is incremented. So
> > the logic of using and incrementing the timestamp id should be atomic
> > per port.
>
> Have you actually observed this race in practice?
>
> All transmit calls are serialized by the netdev transmit spinlock.
>
> Let's not add locking if it is not actually necessary.

It's a bit more complicated.
This code is also used from DSA, and DSA now declares NETIF_F_LLTX.

  reply	other threads:[~2020-09-17 23:43 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 18:22 [PATCH net 0/7] Bugfixes in Microsemi Ocelot switch driver Vladimir Oltean
2020-09-15 18:22 ` [PATCH net 1/7] net: mscc: ocelot: fix race condition with TX timestamping Vladimir Oltean
2020-09-15 18:22 ` [PATCH net 2/7] net: mscc: ocelot: add locking for the port TX timestamp ID Vladimir Oltean
2020-09-16 11:12   ` Alexandre Belloni
2020-09-16 12:25     ` Vladimir Oltean
2020-09-17  0:19   ` David Miller
2020-09-17 23:43     ` Vladimir Oltean [this message]
2020-09-17 23:57       ` David Miller
2020-09-15 18:22 ` [PATCH net 3/7] net: dsa: seville: fix buffer size of the queue system Vladimir Oltean
2020-09-15 18:22 ` [PATCH net 4/7] net: mscc: ocelot: check for errors on memory allocation of ports Vladimir Oltean
2020-09-17  0:21   ` David Miller
2020-09-15 18:22 ` [PATCH net 5/7] net: mscc: ocelot: error checking when calling ocelot_init() Vladimir Oltean
2020-09-17  0:24   ` David Miller
2020-09-15 18:22 ` [PATCH net 6/7] net: mscc: ocelot: refactor ports parsing code into a dedicated function Vladimir Oltean
2020-09-15 18:22 ` [PATCH net 7/7] net: mscc: ocelot: unregister net devices on unbind Vladimir Oltean
2020-09-15 21:19 ` [PATCH net 0/7] Bugfixes in Microsemi Ocelot switch driver Horatiu Vultur
2020-09-16  9:56 ` Alexandre Belloni

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