From patchwork Tue Jul 30 19:26:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Golle X-Patchwork-Id: 13747817 Received: from pidgin.makrotopia.org (pidgin.makrotopia.org [185.142.180.65]) (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 F1EEE1AA3C5; Tue, 30 Jul 2024 19:26:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.142.180.65 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722367616; cv=none; b=RNmbzQ3aa9geIwIpVB/h0vNx2caitDGMZpEdLx5UuLdVXqAyQBlkQKtlHm3Or0TGAyPNnxXmHmwHacEOXeunycudpOHDTRUoah82+LRVpuLmrKOh1XY28glsGHt+3EFtxJctkIrmfdctUMnianv+aigX8AKTDUaEbEGEskqHepw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722367616; c=relaxed/simple; bh=amJzB5NcNAWV7wK3o3+i8FZDKA6RWy8Btwkm9lbCgX8=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bW+XuFRsI73bMeToU17Hqr7zZoC/DkLwSfiOWdzAPuGEiMbfzJs2HsH7e03yPvA2bDmULa3o9tZ41VEh6j5jkOFdaNri5Xya9j/tKXrsbhDH6U+hYtMr+SNt+FzFGa9/9R7cePqHDz5Xp609grVjYVm3hDh3fV6pwj6Z0E4nuoc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=makrotopia.org; spf=pass smtp.mailfrom=makrotopia.org; arc=none smtp.client-ip=185.142.180.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=makrotopia.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=makrotopia.org Received: from local by pidgin.makrotopia.org with esmtpsa (TLS1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.98) (envelope-from ) id 1sYsUg-000000003EJ-1BpC; Tue, 30 Jul 2024 19:26:46 +0000 Date: Tue, 30 Jul 2024 20:26:42 +0100 From: Daniel Golle To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jens Axboe , Daniel Golle , Christian Brauner , Al Viro , Li Lingfeng , Ming Lei , Christian Heusel , =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= , Felix Fietkau , John Crispin , Chad Monroe , Yangyu Chen , Tianling Shen , Chuanhong Guo , Chen Minqiang , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH v5 3/4] block: add support for notifications Message-ID: References: Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Add notifier block to notify other subsystems about the addition or removal of block devices. Signed-off-by: Daniel Golle --- block/Kconfig | 6 +++ block/Makefile | 1 + block/blk-notify.c | 87 ++++++++++++++++++++++++++++++++++++++++++ include/linux/blkdev.h | 11 ++++++ 4 files changed, 105 insertions(+) create mode 100644 block/blk-notify.c diff --git a/block/Kconfig b/block/Kconfig index 5b623b876d3b4..67cd4f92378af 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -209,6 +209,12 @@ config BLK_INLINE_ENCRYPTION_FALLBACK by falling back to the kernel crypto API when inline encryption hardware is not present. +config BLOCK_NOTIFIERS + bool "Enable support for notifications in block layer" + help + Enable this option to provide notifiers for other subsystems + upon addition or removal of block devices. + source "block/partitions/Kconfig" config BLK_MQ_PCI diff --git a/block/Makefile b/block/Makefile index ddfd21c1a9ffc..a131fa7d6b26e 100644 --- a/block/Makefile +++ b/block/Makefile @@ -38,3 +38,4 @@ obj-$(CONFIG_BLK_INLINE_ENCRYPTION) += blk-crypto.o blk-crypto-profile.o \ blk-crypto-sysfs.o obj-$(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) += blk-crypto-fallback.o obj-$(CONFIG_BLOCK_HOLDER_DEPRECATED) += holder.o +obj-$(CONFIG_BLOCK_NOTIFIERS) += blk-notify.o diff --git a/block/blk-notify.c b/block/blk-notify.c new file mode 100644 index 0000000000000..fd727288ea19a --- /dev/null +++ b/block/blk-notify.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Notifiers for addition and removal of block devices + * + * Copyright (c) 2024 Daniel Golle + */ + +#include +#include +#include + +#include "blk.h" + +struct blk_device_list { + struct device *dev; + struct list_head list; +}; + +static RAW_NOTIFIER_HEAD(blk_notifier_list); +static DEFINE_MUTEX(blk_notifier_lock); +static LIST_HEAD(blk_devices); + +void blk_register_notify(struct notifier_block *nb) +{ + struct blk_device_list *existing_blkdev; + + mutex_lock(&blk_notifier_lock); + raw_notifier_chain_register(&blk_notifier_list, nb); + + list_for_each_entry(existing_blkdev, &blk_devices, list) + nb->notifier_call(nb, BLK_DEVICE_ADD, existing_blkdev->dev); + + mutex_unlock(&blk_notifier_lock); +} +EXPORT_SYMBOL_GPL(blk_register_notify); + +void blk_unregister_notify(struct notifier_block *nb) +{ + mutex_lock(&blk_notifier_lock); + raw_notifier_chain_unregister(&blk_notifier_list, nb); + mutex_unlock(&blk_notifier_lock); +} +EXPORT_SYMBOL_GPL(blk_unregister_notify); + +static int blk_call_notifier_add(struct device *dev) +{ + struct blk_device_list *new_blkdev; + + new_blkdev = kmalloc(sizeof(*new_blkdev), GFP_KERNEL); + if (!new_blkdev) + return -ENOMEM; + + new_blkdev->dev = dev; + mutex_lock(&blk_notifier_lock); + list_add_tail(&new_blkdev->list, &blk_devices); + raw_notifier_call_chain(&blk_notifier_list, BLK_DEVICE_ADD, dev); + mutex_unlock(&blk_notifier_lock); + return 0; +} + +static void blk_call_notifier_remove(struct device *dev) +{ + struct blk_device_list *old_blkdev, *tmp; + + mutex_lock(&blk_notifier_lock); + list_for_each_entry_safe(old_blkdev, tmp, &blk_devices, list) { + if (old_blkdev->dev != dev) + continue; + + list_del(&old_blkdev->list); + kfree(old_blkdev); + } + raw_notifier_call_chain(&blk_notifier_list, BLK_DEVICE_REMOVE, dev); + mutex_unlock(&blk_notifier_lock); +} + +static struct class_interface blk_notifications_bus_interface __refdata = { + .class = &block_class, + .add_dev = &blk_call_notifier_add, + .remove_dev = &blk_call_notifier_remove, +}; + +static int __init blk_notifications_init(void) +{ + return class_interface_register(&blk_notifications_bus_interface); +} +device_initcall(blk_notifications_init); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index e85ec73a07d57..2f871158d2860 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1682,4 +1682,15 @@ static inline bool bdev_can_atomic_write(struct block_device *bdev) #define DEFINE_IO_COMP_BATCH(name) struct io_comp_batch name = { } + +#define BLK_DEVICE_ADD 1 +#define BLK_DEVICE_REMOVE 2 +#if defined(CONFIG_BLOCK_NOTIFIERS) +void blk_register_notify(struct notifier_block *nb); +void blk_unregister_notify(struct notifier_block *nb); +#else +static inline void blk_register_notify(struct notifier_block *nb) { }; +static inline void blk_unregister_notify(struct notifier_block *nb) { }; +#endif + #endif /* _LINUX_BLKDEV_H */