From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.9 required=5.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 14B7D7E3E1 for ; Wed, 8 Aug 2018 16:16:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729760AbeHHSgC (ORCPT ); Wed, 8 Aug 2018 14:36:02 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:58650 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727749AbeHHSgC (ORCPT ); Wed, 8 Aug 2018 14:36:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=Z8Ky+5gXzYnaq2MBzxV20ahONgBUDtpNrpCMSUQiEhI=; b=3GCshXzG1aylFJ/WV7OaFsLzVg01YcYeu/dErP9n73z3F/Xey7nxywIZuDlh9SPTr9uwmIU2jymu9fwrcJxeyKgMMo3irVJli2+os2zy36K25R+62rQwnvVrY27ROY8DX2r+rUZuQfYFN4kykODz57Fx/Q9gOWE0yv/H7xuhq7A=; Received: from andrew by vps0.lunn.ch with local (Exim 4.84_2) (envelope-from ) id 1fnR5t-00077y-PJ; Wed, 08 Aug 2018 18:13:53 +0200 Date: Wed, 8 Aug 2018 18:13:53 +0200 From: Andrew Lunn To: Bartosz Golaszewski Cc: Jonathan Corbet , Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Grygorii Strashko , "David S . Miller" , Srinivas Kandagatla , Naren , Mauro Carvalho Chehab , Andrew Morton , Lukas Wunner , Dan Carpenter , Florian Fainelli , Ivan Khoronzhuk , Sven Van Asbroeck , Paolo Abeni , Alban Bedel , Rob Herring , David Lechner , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, netdev@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH 03/28] nvmem: add a notifier chain Message-ID: <20180808161353.GF7275@lunn.ch> References: <20180808153150.23444-1-brgl@bgdev.pl> <20180808153150.23444-4-brgl@bgdev.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180808153150.23444-4-brgl@bgdev.pl> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, Aug 08, 2018 at 05:31:25PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Add a blocking notifier chain with two events (add and remove) so that > users can get notified about the addition of nvmem devices they're > waiting for. > > We'll use this instead of the at24 setup callback in the mityomapl138 > board file. Hi Bartosz What context is this notifier chain called in? I did something similar using the i2c notifier to try to work around the impending disappearing of the setup callback. But i got lockdep splats, because the notifier was called while some locks were being held, so it was not possible to register other i2c devices. The at24 setup callback is done as part of probe, so no important locks are held. Are any locks held when this notifier chain is called? Thanks Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Lunn Subject: Re: [PATCH 03/28] nvmem: add a notifier chain Date: Wed, 8 Aug 2018 18:13:53 +0200 Message-ID: <20180808161353.GF7275@lunn.ch> References: <20180808153150.23444-1-brgl@bgdev.pl> <20180808153150.23444-4-brgl@bgdev.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180808153150.23444-4-brgl@bgdev.pl> Sender: linux-kernel-owner@vger.kernel.org To: Bartosz Golaszewski Cc: Jonathan Corbet , Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Grygorii Strashko , "David S . Miller" , Srinivas Kandagatla , Naren , Mauro Carvalho Chehab , Andrew Morton , Lukas Wunner , Dan Carpenter List-Id: linux-i2c@vger.kernel.org On Wed, Aug 08, 2018 at 05:31:25PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Add a blocking notifier chain with two events (add and remove) so that > users can get notified about the addition of nvmem devices they're > waiting for. > > We'll use this instead of the at24 setup callback in the mityomapl138 > board file. Hi Bartosz What context is this notifier chain called in? I did something similar using the i2c notifier to try to work around the impending disappearing of the setup callback. But i got lockdep splats, because the notifier was called while some locks were being held, so it was not possible to register other i2c devices. The at24 setup callback is done as part of probe, so no important locks are held. Are any locks held when this notifier chain is called? Thanks Andrew From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 8 Aug 2018 18:13:53 +0200 From: Andrew Lunn To: Bartosz Golaszewski Cc: Jonathan Corbet , Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Grygorii Strashko , "David S . Miller" , Srinivas Kandagatla , Naren , Mauro Carvalho Chehab , Andrew Morton , Lukas Wunner , Dan Carpenter , Florian Fainelli , Ivan Khoronzhuk , Sven Van Asbroeck , Paolo Abeni , Alban Bedel , Rob Herring , David Lechner , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, netdev@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH 03/28] nvmem: add a notifier chain Message-ID: <20180808161353.GF7275@lunn.ch> References: <20180808153150.23444-1-brgl@bgdev.pl> <20180808153150.23444-4-brgl@bgdev.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180808153150.23444-4-brgl@bgdev.pl> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Aug 08, 2018 at 05:31:25PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Add a blocking notifier chain with two events (add and remove) so that > users can get notified about the addition of nvmem devices they're > waiting for. > > We'll use this instead of the at24 setup callback in the mityomapl138 > board file. Hi Bartosz What context is this notifier chain called in? I did something similar using the i2c notifier to try to work around the impending disappearing of the setup callback. But i got lockdep splats, because the notifier was called while some locks were being held, so it was not possible to register other i2c devices. The at24 setup callback is done as part of probe, so no important locks are held. Are any locks held when this notifier chain is called? Thanks Andrew From mboxrd@z Thu Jan 1 00:00:00 1970 From: andrew@lunn.ch (Andrew Lunn) Date: Wed, 8 Aug 2018 18:13:53 +0200 Subject: [PATCH 03/28] nvmem: add a notifier chain In-Reply-To: <20180808153150.23444-4-brgl@bgdev.pl> References: <20180808153150.23444-1-brgl@bgdev.pl> <20180808153150.23444-4-brgl@bgdev.pl> Message-ID: <20180808161353.GF7275@lunn.ch> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Aug 08, 2018 at 05:31:25PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Add a blocking notifier chain with two events (add and remove) so that > users can get notified about the addition of nvmem devices they're > waiting for. > > We'll use this instead of the at24 setup callback in the mityomapl138 > board file. Hi Bartosz What context is this notifier chain called in? I did something similar using the i2c notifier to try to work around the impending disappearing of the setup callback. But i got lockdep splats, because the notifier was called while some locks were being held, so it was not possible to register other i2c devices. The at24 setup callback is done as part of probe, so no important locks are held. Are any locks held when this notifier chain is called? Thanks Andrew From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Lunn Subject: Re: [PATCH 03/28] nvmem: add a notifier chain Date: Wed, 8 Aug 2018 18:13:53 +0200 Message-ID: <20180808161353.GF7275@lunn.ch> References: <20180808153150.23444-1-brgl@bgdev.pl> <20180808153150.23444-4-brgl@bgdev.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jonathan Corbet , Sekhar Nori , Kevin Hilman , Russell King , Arnd Bergmann , Greg Kroah-Hartman , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Grygorii Strashko , "David S . Miller" , Srinivas Kandagatla , Naren , Mauro Carvalho Chehab , Andrew Morton , Lukas Wunner , Dan Carpenter Return-path: Content-Disposition: inline In-Reply-To: <20180808153150.23444-4-brgl@bgdev.pl> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, Aug 08, 2018 at 05:31:25PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Add a blocking notifier chain with two events (add and remove) so that > users can get notified about the addition of nvmem devices they're > waiting for. > > We'll use this instead of the at24 setup callback in the mityomapl138 > board file. Hi Bartosz What context is this notifier chain called in? I did something similar using the i2c notifier to try to work around the impending disappearing of the setup callback. But i got lockdep splats, because the notifier was called while some locks were being held, so it was not possible to register other i2c devices. The at24 setup callback is done as part of probe, so no important locks are held. Are any locks held when this notifier chain is called? Thanks Andrew