Attachment 314154 Details for Bug 438761 – ABI workaround for bus notifications

ABI workaround for bus notifications

abi_workaround_for_bus_register_notification (text/plain), 7.38 KB, created by IBM Bug Proxy on 2008-08-13 00:40:41 UTC

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Creator: IBM Bug Proxy

Created: 2008-08-13 00:40:41 UTC

Size: 7.38 KB

patch

obsolete

>Previous patch breaks kernel ABI.
>
>This is the workaround to avoid the breakage.
>
>Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
>-----
>Index: linux-2.6.18.ppc64/include/linux/device.h
>===================================================================
>--- linux-2.6.18.ppc64.orig/include/linux/device.h
>+++ linux-2.6.18.ppc64/include/linux/device.h
>@@ -41,8 +41,6 @@ struct bus_type {
> 	struct klist		klist_devices;
> 	struct klist		klist_drivers;
> 
>-	struct blocking_notifier_head bus_notifier;
>-
> 	struct bus_attribute	* bus_attrs;
> 	struct device_attribute	* dev_attrs;
> 	struct driver_attribute	* drv_attrs;
>@@ -85,6 +83,7 @@ extern int bus_register_notifier(struct 
> 					struct notifier_block *nb);
> extern int bus_unregister_notifier(struct bus_type *bus,
> 					struct notifier_block *nb);
>+extern struct blocking_notifier_head *get_notifier_for_bus(struct bus_type *bus);
> 
> /* All 4 notifers below get called with the target struct device *
>  * as an argument. Note that those functions are likely to be called
>Index: linux-2.6.18.ppc64/drivers/base/bus.c
>===================================================================
>--- linux-2.6.18.ppc64.orig/drivers/base/bus.c
>+++ linux-2.6.18.ppc64/drivers/base/bus.c
>@@ -671,6 +671,79 @@ static void klist_drivers_put(struct kli
> 	put_driver(drv);
> }
> 
>+#define NUM_BUCKETS 64
>+#define MASK_BUCKETS (NUM_BUCKETS - 1)
>+static struct list_head _bus_buckets[NUM_BUCKETS];
>+struct bus_type_nb {
>+	struct list_head list;
>+	struct bus_type *bus;
>+	struct blocking_notifier_head notifier;
>+};
>+
>+static void init_buckets(struct list_head *buckets)
>+{
>+	unsigned int i;
>+
>+	for (i = 0; i < NUM_BUCKETS; i++)
>+		INIT_LIST_HEAD(buckets + i);
>+}
>+
>+static unsigned int hash_str(const void *bus)
>+{
>+	const unsigned int hash_mult = 2654435387U;
>+	unsigned int h = 0;
>+	char *str = (char *) &bus;
>+	int i;
>+
>+	for (i = 0; i < sizeof(void *); i++)
>+		h = (h + (unsigned int) str[i]) * hash_mult;
>+
>+	return h & MASK_BUCKETS;
>+}
>+
>+static struct bus_type_nb *__get_cell(const void *bus)
>+{
>+	struct bus_type_nb *cell;
>+	unsigned int h = hash_str(bus);
>+
>+	list_for_each_entry(cell, _bus_buckets + h, list)
>+		if (cell->bus == bus)
>+			return cell;
>+	return NULL;
>+}
>+
>+static struct blocking_notifier_head *alloc_save_notifier_for_bus(struct bus_type *bus)
>+{
>+	struct bus_type_nb *cell = __get_cell(bus);
>+
>+	if (cell) {
>+		printk(KERN_ERR "bus %p trying to reallocate notifier head\n", bus);
>+		return NULL;
>+	}
>+	cell = kzalloc(sizeof(struct bus_type_nb *), GFP_KERNEL);
>+	if (!cell)
>+		return NULL;
>+	cell->bus = bus;
>+	list_add(&cell->list, _bus_buckets + hash_str(bus));
>+	printk(KERN_ERR "alloced notifier head for bus %p\n", bus);
>+	return &cell->notifier;
>+}
>+
>+static void free_notifier_for_bus(struct bus_type *bus)
>+{
>+	struct bus_type_nb *cell = __get_cell(bus);
>+	if (cell) {
>+		list_del(&cell->list);
>+		kfree(cell);
>+	}
>+}
>+
>+struct blocking_notifier_head *get_notifier_for_bus(struct bus_type *bus)
>+{
>+	struct bus_type_nb *cell = __get_cell(bus);
>+	return cell ? &cell->notifier : NULL;
>+}
>+
> /**
>  *	bus_register - register a bus with the system.
>  *	@bus:	bus.
>@@ -681,9 +754,14 @@ static void klist_drivers_put(struct kli
>  */
> int bus_register(struct bus_type * bus)
> {
>-	int retval;
>+	int retval = -ENOMEM;
>+	struct blocking_notifier_head *notifier_head;
>+
>+	notifier_head = alloc_save_notifier_for_bus(bus);
>+	if (!notifier_head)
>+		goto out;
> 
>-	BLOCKING_INIT_NOTIFIER_HEAD(&bus->bus_notifier);
>+	BLOCKING_INIT_NOTIFIER_HEAD(notifier_head);
> 
> 	retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
> 	if (retval)
>@@ -724,13 +802,23 @@ out:
> 
> int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
> {
>-	return blocking_notifier_chain_register(&bus->bus_notifier, nb);
>+	struct blocking_notifier_head *notifier_head;
>+
>+	notifier_head = get_notifier_for_bus(bus);
>+	if (!notifier_head)
>+		return 0;
>+	return blocking_notifier_chain_register(notifier_head, nb);
> }
> EXPORT_SYMBOL_GPL(bus_register_notifier);
> 
> int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
> {
>-	return blocking_notifier_chain_unregister(&bus->bus_notifier, nb);
>+	struct blocking_notifier_head *notifier_head;
>+
>+	notifier_head = get_notifier_for_bus(bus);
>+	if (!notifier_head)
>+		return 0;
>+	return blocking_notifier_chain_unregister(notifier_head, nb);
> }
> EXPORT_SYMBOL_GPL(bus_unregister_notifier);
> 
>@@ -744,6 +832,7 @@ EXPORT_SYMBOL_GPL(bus_unregister_notifie
> void bus_unregister(struct bus_type * bus)
> {
> 	pr_debug("bus %s: unregistering\n", bus->name);
>+	free_notifier_for_bus(bus);
> 	bus_remove_attrs(bus);
> 	kset_unregister(&bus->drivers);
> 	kset_unregister(&bus->devices);
>@@ -752,10 +841,10 @@ void bus_unregister(struct bus_type * bu
> 
> int __init buses_init(void)
> {
>+	init_buckets(_bus_buckets);
> 	return subsystem_register(&bus_subsys);
> }
> 
>-
> EXPORT_SYMBOL_GPL(bus_for_each_dev);
> EXPORT_SYMBOL_GPL(bus_find_device);
> EXPORT_SYMBOL_GPL(bus_for_each_drv);
>Index: linux-2.6.18.ppc64/drivers/base/core.c
>===================================================================
>--- linux-2.6.18.ppc64.orig/drivers/base/core.c
>+++ linux-2.6.18.ppc64/drivers/base/core.c
>@@ -370,9 +370,14 @@ int device_add(struct device *dev)
> 		platform_notify(dev);
> 
> 	/* notify clients of device entry (new way) */
>-	if (dev->bus)
>-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
>+	if (dev->bus) {
>+		struct blocking_notifier_head *notifier_head;
>+
>+		notifier_head = get_notifier_for_bus(dev->bus);
>+		if (notifier_head)
>+			blocking_notifier_call_chain(notifier_head,
> 						BUS_NOTIFY_ADD_DEVICE, dev);
>+	}
>  Done:
>  	kfree(class_name);
> 	put_device(dev);
>@@ -492,9 +497,15 @@ void device_del(struct device * dev)
> 	if (platform_notify_remove)
> 		platform_notify_remove(dev);
> 
>-	if (dev->bus)
>-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
>+	if (dev->bus) {
>+		struct blocking_notifier_head *notifier_head;
>+
>+		notifier_head = get_notifier_for_bus(dev->bus);
>+		if (notifier_head)
>+			blocking_notifier_call_chain(notifier_head,
> 						BUS_NOTIFY_DEL_DEVICE, dev);
>+	}
>+
> 	device_pm_remove(dev);
> 	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
> 	kobject_del(&dev->kobj);
>Index: linux-2.6.18.ppc64/drivers/base/dd.c
>===================================================================
>--- linux-2.6.18.ppc64.orig/drivers/base/dd.c
>+++ linux-2.6.18.ppc64/drivers/base/dd.c
>@@ -45,9 +45,14 @@ void device_bind_driver(struct device * 
> 
> 	pr_debug("bound device '%s' to driver '%s'\n",
> 		 dev->bus_id, dev->driver->name);
>-	if (dev->bus)
>-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
>+	if (dev->bus) {
>+		struct blocking_notifier_head *notifier_head;
>+
>+		notifier_head = get_notifier_for_bus(dev->bus);
>+		if (notifier_head)
>+			blocking_notifier_call_chain(notifier_head,
> 						BUS_NOTIFY_BOUND_DRIVER, dev);
>+	}
> 
> 	klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
> 	sysfs_create_link(&dev->driver->kobj, &dev->kobj,
>@@ -216,10 +221,14 @@ static void __device_release_driver(stru
> 		sysfs_remove_link(&dev->kobj, "driver");
> 		klist_remove(&dev->knode_driver);
> 
>-		if (dev->bus)
>-			blocking_notifier_call_chain(&dev->bus->bus_notifier,
>-						BUS_NOTIFY_UNBIND_DRIVER,
>-						dev);
>+		if (dev->bus) {
>+			struct blocking_notifier_head *notifier_head;
>+
>+			notifier_head = get_notifier_for_bus(dev->bus);
>+			if (notifier_head)
>+				blocking_notifier_call_chain(notifier_head,
>+						BUS_NOTIFY_UNBIND_DRIVER, dev);
>+		}
> 		if (dev->bus && dev->bus->remove)
> 			dev->bus->remove(dev);
> 		else if (drv->remove)

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Attachments on bug 438761: 314153 | 314154 | 314155 | 314156 | 314157 | 314158 | 314159 | 314160 | 314161 | 314162 | 314163 | 314339 | 314426 | 314828 | 314829 | 316641