From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3525F2F6927; Fri, 20 Feb 2026 08:09:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771574944; cv=none; b=H3E5B1T8yef1wKLQRmOGRDUYjIfnYBpifPQie+eJZFDWj0niD4b5zt9u6iEyppACj4LAYjV5lxykDl3tqM1cKlQBvt6UNt9X1eyZjWVd9WBUbF+nyjWBFEw0PY2bMDUdO62kGOjvfxD85li3VGdBNPxPoEqb1616nLL6MEyVwwE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771574944; c=relaxed/simple; bh=1HS/wrclX+zdBDMRkBqcSBoNROJP2Zzl7lcfOnIClI0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=H0+Kkx8g3DsFI5++mCWXNOSU6gFHMRGs4+L/tnXmI6ns231tDcIyqAq1Z1edALDwQdtJPJNbrh/pE8KhFECuBci63i5Wt9NKlYNHX7wKr++Cf+V+PWo8QMc4ump9Ir5s8YlMaeTRfp46e9P2AxGCfUiUbWHYHbO+CZkELf4WZqY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i9k8QsPH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="i9k8QsPH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9E49C116C6; Fri, 20 Feb 2026 08:09:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771574943; bh=1HS/wrclX+zdBDMRkBqcSBoNROJP2Zzl7lcfOnIClI0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=i9k8QsPH3jUczGmdVZTZ040HMP9Pg/E3YzPymgLrNPXVUZe8xBYeVaDhJCbVFZBLK UtxMyiZJQcFIljlU269aSAlrUUZ7vVCyh37YCYz2s5fCp3dUHkhY2nhS/5HMe9L++H zSrO9hAvVG+8aGkjYPoTxfdTLqi/BOuQIB4eC59MqsHLlGjmylFBs5yX4H7P3oI4bq Ith4AvTOkjKeZINMtlQnKJz+iZ1n66EAwp/0GUrazSrAQA6yP0vuXYENeebI6L9w5N 5GkO5tHJIxjv8L+rbI3MowGYSroSosFi+HFibfMKyhPGG3f1I/WYD6pHJNBUz8Pu44 SG8xX4+HKwxdg== Date: Fri, 20 Feb 2026 10:08:59 +0200 From: Leon Romanovsky To: Greg Kroah-Hartman Cc: Danilo Krummrich , Tariq Toukan , "Rafael J. Wysocki" , Saeed Mahameed , Mark Bloch , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, Gal Pressman , Moshe Shemesh , Amir Tzin Subject: Re: [PATCH V2] driver core: auxiliary bus: Fix sysfs creation on bind Message-ID: <20260220080859.GC10607@unreal> References: <20260219210435.1769394-1-tariqt@nvidia.com> <2026022040-casualty-dexterity-543c@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2026022040-casualty-dexterity-543c@gregkh> On Fri, Feb 20, 2026 at 07:34:02AM +0100, Greg Kroah-Hartman wrote: > On Fri, Feb 20, 2026 at 12:59:45AM +0100, Danilo Krummrich wrote: > > On Thu Feb 19, 2026 at 10:04 PM CET, Tariq Toukan wrote: > > > +/** > > > + * auxiliary_device_sysfs_irq_dir_init - initialize the IRQ sysfs directory > > > + * @auxdev: auxiliary bus device to initialize the sysfs directory. > > > + * > > > + * This function should be called by drivers to initialize the IRQ directory > > > + * before adding any IRQ sysfs entries. The driver is responsible for ensuring > > > + * this function is called only once and for handling any concurrency control > > > + * if needed. > > > + * > > > + * Drivers must call auxiliary_device_sysfs_irq_dir_destroy() to clean up when > > > + * done. > > > + * > > > + * Return: zero on success or an error code on failure. > > > + */ > > > +int auxiliary_device_sysfs_irq_dir_init(struct auxiliary_device *auxdev) > > > { > > > - int ret = 0; > > > - > > > - guard(mutex)(&auxdev->sysfs.lock); > > > - if (auxdev->sysfs.irq_dir_exists) > > > - return 0; > > > + int ret; > > > > > > - ret = devm_device_add_group(&auxdev->dev, &auxiliary_irqs_group); > > > + ret = sysfs_create_group(&auxdev->dev.kobj, &auxiliary_irqs_group); > > > if (ret) > > > return ret; > > > > > > - auxdev->sysfs.irq_dir_exists = true; > > > xa_init(&auxdev->sysfs.irqs); > > > return 0; > > > } > > > +EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_dir_init); > > > + > > > +/** > > > + * auxiliary_device_sysfs_irq_dir_destroy - destroy the IRQ sysfs directory > > > + * @auxdev: auxiliary bus device to destroy the sysfs directory. > > > + * > > > + * This function should be called by drivers to clean up the IRQ directory > > > + * after all IRQ sysfs entries have been removed. The driver is responsible > > > + * for ensuring all IRQs are removed before calling this function. > > > + */ > > > +void auxiliary_device_sysfs_irq_dir_destroy(struct auxiliary_device *auxdev) > > > +{ > > > + xa_destroy(&auxdev->sysfs.irqs); > > > + sysfs_remove_group(&auxdev->dev.kobj, &auxiliary_irqs_group); > > > +} > > > +EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_dir_destroy); > > > > > > /** > > > * auxiliary_device_sysfs_irq_add - add a sysfs entry for the given IRQ > > > @@ -45,7 +70,8 @@ static int auxiliary_irq_dir_prepare(struct auxiliary_device *auxdev) > > > * @irq: The associated interrupt number. > > > * > > > * This function should be called after auxiliary device have successfully > > > - * received the irq. > > > + * received the irq. The driver must call auxiliary_device_sysfs_irq_dir_init() > > > + * before calling this function for the first time. > > > > I'm not convinced by this approach. This adds two new sources of bugs for > > drivers. > > > > 1. Drivers can now forget to call auxiliary_device_sysfs_irq_dir_init() > > *before* auxiliary_device_sysfs_irq_add(). > > > > 2. Drivers can forget to call auxiliary_device_sysfs_irq_dir_destroy(). > > > > Instead, I suggest to keep the current approach and just replace > > devm_device_add_group() with devm_auxiliary_device_add_group(), which in its > > devres callback additionally clears auxdev->sysfs.irq_dir_exists. > > > > In terms of the auxdev->sysfs.lock, I think this can still be removed, as it > > wasn't needed in the first place. > > > > auxiliary_device_sysfs_irq_add() must only be called from a scope where the > > auxiliary device is guaranteed to be bound, so there can't be a concurrent > > unbind. > > > > There may only be multiple concurrent calls to auxiliary_device_sysfs_irq_add() > > itself, and in this case irq_dir_exists can just be an atomic. > > > > Yes, we're still stuck with an atomic for irq_dir_exists, but the driver API > > remains much simpler and less error prone. > > I agree, your recommendations make sense. Unfortunately no, https://lore.kernel.org/all/20260220080413.GB10607@unreal/. Just to summarize: 1. atomic is not a replacement for locking. 2. drivers already handle this irq thing. 3. init->add->remove->destroy is standard Linux kernel coding pattern. Thanks