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X-CSE-ConnectionGUID: WlFaw+YYS0ygSmEGGGJdJw== X-CSE-MsgGUID: TmsmZ3B3ReScbkx7sIAcag== X-IronPort-AV: E=McAfee;i="6800,10657,11870"; a="90540087" X-IronPort-AV: E=Sophos;i="6.25,215,1779174000"; d="scan'208";a="90540087" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2026 02:12:51 -0700 X-CSE-ConnectionGUID: Zap65IgfRyao47/XSMPIRA== X-CSE-MsgGUID: 2mcW99ImTKyDObLUkRAsdQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,215,1779174000"; d="scan'208";a="287692937" Received: from conormcd-mobl2.ger.corp.intel.com (HELO localhost) ([10.245.244.99]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2026 02:12:44 -0700 Date: Mon, 10 Aug 2026 12:12:41 +0300 From: Andy Shevchenko To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Cc: Eliav Farber , rafael@kernel.org, tony.luck@intel.com, bp@alien8.de, guohanjun@huawei.com, mchehab@kernel.org, xueshuai@linux.alibaba.com, lenb@kernel.org, laurent.pinchart@ideasonboard.com, linusw@kernel.org, brgl@kernel.org, orsonzhai@gmail.com, baolin.wang@linux.alibaba.com, zhang.lyra@gmail.com, jic23@kernel.org, dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, dmitry.torokhov@gmail.com, hansg@kernel.org, ilpo.jarvinen@linux.intel.com, W_Armin@gmx.de, fabio.m.de.francesco@linux.intel.com, kaihengf@nvidia.com, ankita@nvidia.com, leitao@debian.org, pedro.pbg@usp.br, paulmck@kernel.org, frederic@kernel.org, kees@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-pwm@vger.kernel.org, linux-iio@vger.kernel.org, linux-input@vger.kernel.org, platform-driver-x86@vger.kernel.org Subject: Re: [PATCH v4 01/13] notifier: add device-managed registration APIs Message-ID: References: <20260726101739.33170-1-farbere@amazon.com> <20260726101739.33170-2-farbere@amazon.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Mon, Aug 10, 2026 at 12:11:40PM +0300, Andy Shevchenko wrote: > On Mon, Aug 10, 2026 at 06:37:25AM +0200, Uwe Kleine-König wrote: > > On Sun, Jul 26, 2026 at 10:17:27AM +0000, Eliav Farber wrote: ... > > > +{ > > > + struct atomic_notifier_chain_devres *dr; > > > + int ret; > > > + > > > + dr = devres_alloc(devm_atomic_notifier_chain_unregister, > > > + sizeof(*dr), GFP_KERNEL); > > > + if (!dr) > > > + return -ENOMEM; > > > + > > > + ret = atomic_notifier_chain_register(nh, n); > > > + if (ret) { > > > + devres_free(dr); > > > + return ret; > > > + } > > > + > > > + dr->nh = nh; > > > + dr->nb = n; > > > + devres_add(dev, dr); > > > + > > > + return 0; > > > +} > > > +EXPORT_SYMBOL_GPL(devm_atomic_notifier_chain_register); > > > > IMHO devm_atomic_notifier_chain_register() should look as follows: > > > > ret = atomic_notifier_chain_register(nh, n); > > if (ret) > > return ret; > > > > return devm_add_action_or_reset(dev, devm_atomic_notifier_chain_unregister, dr) > > > > which is much easier and includes less details from the inner workings > > of devm. Same for the blocking variant. > > Won't work. We need more than one parameter and hence the whole devres_alloc(). > Please, look closer to the code. And just answering ahead, no, devm_kmalloc() is not good bandaid as it makes code not anyhow better to read and have a downside of memory fragmentation. -- With Best Regards, Andy Shevchenko