From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris brezillon Subject: Re: [RFC PATCH] phylib: mdio: handle register/unregister/register sequence Date: Thu, 22 Aug 2013 17:38:30 +0200 Message-ID: <52163076.2010501@overkiz.com> References: <1377174836-10569-1-git-send-email-b.brezillon@overkiz.com> <20130822152757.GA23163@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Mark Brown , Nick Bowler , Grant Likely , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org To: Greg Kroah-Hartman Return-path: In-Reply-To: <20130822152757.GA23163@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 22/08/2013 17:27, Greg Kroah-Hartman wrote: > On Thu, Aug 22, 2013 at 02:33:56PM +0200, Boris BREZILLON wrote: >> Hello, >> >> This patch is a proposal to support the register/unregister/register >> sequence on a given mdio bus. >> >> I use the register/unregister/register sequence to add a fallback when the >> of_mdiobus_register (this function calls mdiobus_register with phy_mask >> set to ~0) does not register any phy device (because the device tree does >> not define any phy). >> In this case I call mdiobus_unregister and then call mdiobus_register with >> a phy_mask set to 0 to trigger a full mdio bus scan. >> >> I'm not sure this is the right way to do it (this is why I added RFC in the >> subject). >> >> Could someone help me figuring out what I should use to implement my fallback ? >> >> 1) use the register/unregister/register sequence > That will not work. Well, you might think it would work, but then > things randomly start breaking later on. Try it with the > KOBJECT_DELAYED_DESTROY build option in linux-next, and watch things go > "boom" :) > > The rule is, you should never register a kobject/struct device that you > have previously unregistered before, as you really don't know if > unregistering has finished or not. Thanks for your answer. > > sorry, > > greg k-h