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From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Andre Naujoks <nautsch2@gmail.com>
Cc: davem@davemloft.net, Wolfgang Grandegger <wg@grandegger.com>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net 1/3] slip/slcan: added locking in wakeup function
Date: Thu, 19 Sep 2013 11:36:09 +0200	[thread overview]
Message-ID: <523AC589.5040006@pengutronix.de> (raw)
In-Reply-To: <1379093833-4949-2-git-send-email-nautsch2@gmail.com>

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On 09/13/2013 07:37 PM, Andre Naujoks wrote:
> The locking is needed, since the the internal buffer for the CAN frames is
> changed during the wakeup call. This could cause buffer inconsistencies
> under high loads, especially for the outgoing short CAN packet skbuffs.
> 
> The needed locks led to deadlocks before commit
> "5ede52538ee2b2202d9dff5b06c33bfde421e6e4 tty: Remove extra wakeup from pty
> write() path", which removed the direct callback to the wakeup function from the
> tty layer.

What does that mean for older kernels?
(< 5ede52538ee2b2202d9dff5b06c33bfde421e6e4)

> As slcan.c is based on slip.c the issue in the original code is fixed, too.
> 
> Signed-off-by: Andre Naujoks <nautsch2@gmail.com>
Acked-by: Marc Kleine-Budde  <mkl@pengutronix.de>

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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  parent reply	other threads:[~2013-09-19  9:36 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-13 17:37 [PATCH net 0/3] SLCAN/SLIP fixes and performance Andre Naujoks
2013-09-13 17:37 ` [PATCH net 1/3] slip/slcan: added locking in wakeup function Andre Naujoks
2013-09-13 18:45   ` Oliver Hartkopp
2013-09-19  9:36   ` Marc Kleine-Budde [this message]
2013-09-19 10:29     ` Andre Naujoks
2013-09-19 10:35       ` Marc Kleine-Budde
2013-09-19 10:43         ` Peter Hurley
2013-09-13 17:37 ` [PATCH net 2/3] lib: introduce upper case hex ascii helpers Andre Naujoks
2013-09-15  4:27   ` Thiago Farina
2013-09-15  4:35     ` Andrew Morton
2013-09-19  9:38       ` Marc Kleine-Budde
2013-09-19  9:57         ` Oliver Hartkopp
2013-09-13 17:37 ` [PATCH net 3/3] slcan: rewrite of slc_bump and slc_encaps Andre Naujoks
2013-09-13 18:43   ` Oliver Hartkopp
2013-09-19  9:47   ` Marc Kleine-Budde
2013-09-14 10:45 ` [PATCH net 0/3] SLCAN/SLIP fixes and performance Marc Kleine-Budde
2013-09-14 11:22   ` Andre Naujoks
2013-09-20 19:39 ` David Miller

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