From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: [ofa-general] Re: locking requirements when calling dev_set_mtu() Date: Wed, 2 Jul 2008 18:15:52 +0100 Message-ID: <20080702171550.GE17872@solarflare.com> References: <20080702085409.GA13098@mtls03> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev , Roland Dreier , fubar@us.ibm.com, general-list To: Eli Cohen Return-path: Content-Disposition: inline In-Reply-To: <20080702085409.GA13098@mtls03> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: general-bounces@lists.openfabrics.org Errors-To: general-bounces@lists.openfabrics.org List-Id: netdev.vger.kernel.org Eli Cohen wrote: > Hi, > > I have the need to change the MTU of IP over IB from the driver code > and not from the shell. Looking for the right way to do it I came > across the dev_set_mtu() which seems appropriate as it handles all > notifications too. However, it is not clear to me whether I have to > wrap the call to dev_set_mtu() with any locks. Specifically, I was > referred to a mail thread that suggests that I have to use > rtnl_lock()/rtnl_unlock(): > http://marc.info/?l=linux-netdev&m=121201324611292&w=2 [...] Essentially any function that changes net device configuration requires the caller to hold the RTNL lock. This probably ought to be consistently documented through kernel-doc and/or ASSERT_RTNL() though. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job.