mirror of
https://github.com/Ysurac/openmptcprouter.git
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145 lines
4 KiB
Diff
145 lines
4 KiB
Diff
From e07ace307ce598847074a096f408bec0e3a392ed Mon Sep 17 00:00:00 2001
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From: Daniel Golle <daniel@makrotopia.org>
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Date: Thu, 30 May 2024 03:14:34 +0100
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Subject: [PATCH 3/9] block: add support for notifications
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Add notifier block to notify other subsystems about the addition or
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removal of block devices.
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Signed-off-by: Daniel Golle <daniel@makrotopia.org>
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---
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block/Kconfig | 6 +++
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block/Makefile | 1 +
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block/blk-notify.c | 88 ++++++++++++++++++++++++++++++++++++++++++
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include/linux/blkdev.h | 8 ++++
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4 files changed, 103 insertions(+)
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create mode 100644 block/blk-notify.c
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--- a/block/Kconfig
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+++ b/block/Kconfig
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@@ -208,6 +208,12 @@ config BLK_INLINE_ENCRYPTION_FALLBACK
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by falling back to the kernel crypto API when inline
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encryption hardware is not present.
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+config BLOCK_NOTIFIERS
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+ bool "Enable support for notifications in block layer"
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+ help
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+ Enable this option to provide notifiers for other subsystems
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+ upon addition or removal of block devices.
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+
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source "block/partitions/Kconfig"
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config BLK_MQ_PCI
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--- a/block/Makefile
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+++ b/block/Makefile
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@@ -40,3 +40,4 @@ obj-$(CONFIG_BLK_INLINE_ENCRYPTION) += b
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blk-crypto-sysfs.o
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obj-$(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) += blk-crypto-fallback.o
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obj-$(CONFIG_BLOCK_HOLDER_DEPRECATED) += holder.o
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+obj-$(CONFIG_BLOCK_NOTIFIERS) += blk-notify.o
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--- /dev/null
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+++ b/block/blk-notify.c
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@@ -0,0 +1,88 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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+/*
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+ * Notifiers for addition and removal of block devices
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+ *
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+ * Copyright (c) 2024 Daniel Golle <daniel@makrotopia.org>
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+ */
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+
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+#include <linux/list.h>
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+#include <linux/mutex.h>
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+#include <linux/notifier.h>
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+
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+#include "blk.h"
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+
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+struct blk_device_list {
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+ struct device *dev;
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+ struct list_head list;
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+};
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+
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+static RAW_NOTIFIER_HEAD(blk_notifier_list);
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+static DEFINE_MUTEX(blk_notifier_lock);
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+static LIST_HEAD(blk_devices);
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+
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+void blk_register_notify(struct notifier_block *nb)
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+{
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+ struct blk_device_list *existing_blkdev;
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+
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+ mutex_lock(&blk_notifier_lock);
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+ raw_notifier_chain_register(&blk_notifier_list, nb);
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+
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+ list_for_each_entry(existing_blkdev, &blk_devices, list)
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+ nb->notifier_call(nb, BLK_DEVICE_ADD, existing_blkdev->dev);
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+
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+ mutex_unlock(&blk_notifier_lock);
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+}
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+EXPORT_SYMBOL_GPL(blk_register_notify);
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+
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+void blk_unregister_notify(struct notifier_block *nb)
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+{
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+ mutex_lock(&blk_notifier_lock);
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+ raw_notifier_chain_unregister(&blk_notifier_list, nb);
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+ mutex_unlock(&blk_notifier_lock);
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+}
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+EXPORT_SYMBOL_GPL(blk_unregister_notify);
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+
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+static int blk_call_notifier_add(struct device *dev)
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+{
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+ struct blk_device_list *new_blkdev;
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+
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+ new_blkdev = kmalloc(sizeof(*new_blkdev), GFP_KERNEL);
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+ if (!new_blkdev)
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+ return -ENOMEM;
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+
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+ new_blkdev->dev = dev;
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+ mutex_lock(&blk_notifier_lock);
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+ list_add_tail(&new_blkdev->list, &blk_devices);
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+ raw_notifier_call_chain(&blk_notifier_list, BLK_DEVICE_ADD, dev);
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+ mutex_unlock(&blk_notifier_lock);
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+
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+ return 0;
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+}
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+
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+static void blk_call_notifier_remove(struct device *dev)
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+{
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+ struct blk_device_list *old_blkdev, *tmp;
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+
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+ mutex_lock(&blk_notifier_lock);
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+ list_for_each_entry_safe(old_blkdev, tmp, &blk_devices, list) {
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+ if (old_blkdev->dev != dev)
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+ continue;
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+
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+ list_del(&old_blkdev->list);
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+ kfree(old_blkdev);
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+ }
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+ raw_notifier_call_chain(&blk_notifier_list, BLK_DEVICE_REMOVE, dev);
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+ mutex_unlock(&blk_notifier_lock);
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+}
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+
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+static struct class_interface blk_notifications_bus_interface __refdata = {
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+ .class = &block_class,
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+ .add_dev = &blk_call_notifier_add,
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+ .remove_dev = &blk_call_notifier_remove,
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+};
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+
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+static int __init blk_notifications_init(void)
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+{
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+ return class_interface_register(&blk_notifications_bus_interface);
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+}
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+device_initcall(blk_notifications_init);
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--- a/include/linux/blkdev.h
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+++ b/include/linux/blkdev.h
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@@ -1564,4 +1564,12 @@ struct io_comp_batch {
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#define DEFINE_IO_COMP_BATCH(name) struct io_comp_batch name = { }
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+
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+#ifdef CONFIG_BLOCK_NOTIFIERS
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+#define BLK_DEVICE_ADD 1
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+#define BLK_DEVICE_REMOVE 2
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+void blk_register_notify(struct notifier_block *nb);
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+void blk_unregister_notify(struct notifier_block *nb);
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+#endif
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+
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#endif /* _LINUX_BLKDEV_H */
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