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			In the match() callback, the struct device_driver * should not be changed, so change the function callback to be a const *. This is one step of many towards making the driver core safe to have struct device_driver in read-only memory. Because the match() callback is in all busses, all busses are modified to handle this properly. This does entail switching some container_of() calls to container_of_const() to properly handle the constant *. For some busses, like PCI and USB and HV, the const * is cast away in the match callback as those busses do want to modify those structures at this point in time (they have a local lock in the driver structure.) That will have to be changed in the future if they wish to have their struct device * in read-only-memory. Cc: Rafael J. Wysocki <rafael@kernel.org> Reviewed-by: Alex Elder <elder@kernel.org> Acked-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
		
			
				
	
	
		
			248 lines
		
	
	
	
		
			8.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			248 lines
		
	
	
	
		
			8.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /******************************************************************************
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|  * xenbus.h
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|  *
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|  * Talks to Xen Store to figure out what devices we have.
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|  *
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|  * Copyright (C) 2005 Rusty Russell, IBM Corporation
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|  * Copyright (C) 2005 XenSource Ltd.
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|  *
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|  * This program is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU General Public License version 2
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|  * as published by the Free Software Foundation; or, when distributed
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|  * separately from the Linux kernel or incorporated into other
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|  * software packages, subject to the following license:
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|  *
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|  * Permission is hereby granted, free of charge, to any person obtaining a copy
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|  * of this source file (the "Software"), to deal in the Software without
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|  * restriction, including without limitation the rights to use, copy, modify,
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|  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
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|  * and to permit persons to whom the Software is furnished to do so, subject to
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|  * the following conditions:
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|  *
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|  * The above copyright notice and this permission notice shall be included in
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|  * all copies or substantial portions of the Software.
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|  *
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|  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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|  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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|  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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|  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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|  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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|  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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|  * IN THE SOFTWARE.
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|  */
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| 
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| #ifndef _XEN_XENBUS_H
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| #define _XEN_XENBUS_H
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| 
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| #include <linux/device.h>
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| #include <linux/notifier.h>
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| #include <linux/mutex.h>
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| #include <linux/export.h>
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| #include <linux/fs.h>
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| #include <linux/completion.h>
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| #include <linux/init.h>
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| #include <linux/slab.h>
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| #include <linux/semaphore.h>
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| #include <xen/interface/xen.h>
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| #include <xen/interface/grant_table.h>
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| #include <xen/interface/io/xenbus.h>
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| #include <xen/interface/io/xs_wire.h>
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| #include <xen/interface/event_channel.h>
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| 
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| #define XENBUS_MAX_RING_GRANT_ORDER 4
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| #define XENBUS_MAX_RING_GRANTS      (1U << XENBUS_MAX_RING_GRANT_ORDER)
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| 
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| /* Register callback to watch this node. */
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| struct xenbus_watch
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| {
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| 	struct list_head list;
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| 
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| 	/* Path being watched. */
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| 	const char *node;
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| 
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| 	unsigned int nr_pending;
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| 
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| 	/*
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| 	 * Called just before enqueing new event while a spinlock is held.
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| 	 * The event will be discarded if this callback returns false.
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| 	 */
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| 	bool (*will_handle)(struct xenbus_watch *,
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| 			      const char *path, const char *token);
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| 
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| 	/* Callback (executed in a process context with no locks held). */
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| 	void (*callback)(struct xenbus_watch *,
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| 			 const char *path, const char *token);
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| };
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| 
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| 
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| /* A xenbus device. */
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| struct xenbus_device {
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| 	const char *devicetype;
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| 	const char *nodename;
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| 	const char *otherend;
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| 	int otherend_id;
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| 	struct xenbus_watch otherend_watch;
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| 	struct device dev;
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| 	enum xenbus_state state;
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| 	struct completion down;
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| 	struct work_struct work;
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| 	struct semaphore reclaim_sem;
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| 
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| 	/* Event channel based statistics and settings. */
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| 	atomic_t event_channels;
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| 	atomic_t events;
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| 	atomic_t spurious_events;
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| 	atomic_t jiffies_eoi_delayed;
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| 	unsigned int spurious_threshold;
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| };
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| 
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| #define to_xenbus_device(__dev)	container_of_const(__dev, struct xenbus_device, dev)
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| 
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| struct xenbus_device_id
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| {
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| 	/* .../device/<device_type>/<identifier> */
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| 	char devicetype[32]; 	/* General class of device. */
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| };
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| 
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| /* A xenbus driver. */
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| struct xenbus_driver {
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| 	const char *name;       /* defaults to ids[0].devicetype */
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| 	const struct xenbus_device_id *ids;
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| 	bool allow_rebind; /* avoid setting xenstore closed during remove */
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| 	bool not_essential;     /* is not mandatory for boot progress */
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| 	int (*probe)(struct xenbus_device *dev,
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| 		     const struct xenbus_device_id *id);
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| 	void (*otherend_changed)(struct xenbus_device *dev,
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| 				 enum xenbus_state backend_state);
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| 	void (*remove)(struct xenbus_device *dev);
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| 	int (*suspend)(struct xenbus_device *dev);
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| 	int (*resume)(struct xenbus_device *dev);
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| 	int (*uevent)(const struct xenbus_device *, struct kobj_uevent_env *);
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| 	struct device_driver driver;
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| 	int (*read_otherend_details)(struct xenbus_device *dev);
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| 	int (*is_ready)(struct xenbus_device *dev);
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| 	void (*reclaim_memory)(struct xenbus_device *dev);
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| };
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| 
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| #define to_xenbus_driver(__drv)	container_of_const(__drv, struct xenbus_driver, driver)
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| 
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| int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
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| 					    struct module *owner,
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| 					    const char *mod_name);
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| int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
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| 					   struct module *owner,
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| 					   const char *mod_name);
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| 
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| #define xenbus_register_frontend(drv) \
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| 	__xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
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| #define xenbus_register_backend(drv) \
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| 	__xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
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| 
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| void xenbus_unregister_driver(struct xenbus_driver *drv);
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| 
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| struct xenbus_transaction
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| {
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| 	u32 id;
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| };
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| 
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| /* Nil transaction ID. */
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| #define XBT_NIL ((struct xenbus_transaction) { 0 })
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| 
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| char **xenbus_directory(struct xenbus_transaction t,
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| 			const char *dir, const char *node, unsigned int *num);
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| void *xenbus_read(struct xenbus_transaction t,
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| 		  const char *dir, const char *node, unsigned int *len);
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| int xenbus_write(struct xenbus_transaction t,
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| 		 const char *dir, const char *node, const char *string);
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| int xenbus_mkdir(struct xenbus_transaction t,
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| 		 const char *dir, const char *node);
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| int xenbus_exists(struct xenbus_transaction t,
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| 		  const char *dir, const char *node);
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| int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
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| int xenbus_transaction_start(struct xenbus_transaction *t);
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| int xenbus_transaction_end(struct xenbus_transaction t, int abort);
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| 
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| /* Single read and scanf: returns -errno or num scanned if > 0. */
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| __scanf(4, 5)
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| int xenbus_scanf(struct xenbus_transaction t,
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| 		 const char *dir, const char *node, const char *fmt, ...);
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| 
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| /* Read an (optional) unsigned value. */
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| unsigned int xenbus_read_unsigned(const char *dir, const char *node,
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| 				  unsigned int default_val);
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| 
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| /* Single printf and write: returns -errno or 0. */
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| __printf(4, 5)
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| int xenbus_printf(struct xenbus_transaction t,
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| 		  const char *dir, const char *node, const char *fmt, ...);
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| 
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| /* Generic read function: NULL-terminated triples of name,
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|  * sprintf-style type string, and pointer. Returns 0 or errno.*/
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| int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
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| 
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| /* notifer routines for when the xenstore comes up */
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| extern int xenstored_ready;
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| int register_xenstore_notifier(struct notifier_block *nb);
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| void unregister_xenstore_notifier(struct notifier_block *nb);
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| 
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| int register_xenbus_watch(struct xenbus_watch *watch);
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| void unregister_xenbus_watch(struct xenbus_watch *watch);
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| void xs_suspend(void);
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| void xs_resume(void);
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| void xs_suspend_cancel(void);
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| 
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| struct work_struct;
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| 
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| #define XENBUS_IS_ERR_READ(str) ({			\
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| 	if (!IS_ERR(str) && strlen(str) == 0) {		\
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| 		kfree(str);				\
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| 		str = ERR_PTR(-ERANGE);			\
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| 	}						\
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| 	IS_ERR(str);					\
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| })
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| 
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| #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
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| 
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| int xenbus_watch_path(struct xenbus_device *dev, const char *path,
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| 		      struct xenbus_watch *watch,
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| 		      bool (*will_handle)(struct xenbus_watch *,
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| 					  const char *, const char *),
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| 		      void (*callback)(struct xenbus_watch *,
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| 				       const char *, const char *));
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| __printf(5, 6)
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| int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
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| 			 bool (*will_handle)(struct xenbus_watch *,
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| 					     const char *, const char *),
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| 			 void (*callback)(struct xenbus_watch *,
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| 					  const char *, const char *),
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| 			 const char *pathfmt, ...);
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| 
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| int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
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| int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
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| 		      unsigned int nr_pages, grant_ref_t *grefs);
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| void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages,
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| 			  grant_ref_t *grefs);
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| int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
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| 			   unsigned int nr_grefs, void **vaddr);
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| 
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| int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
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| 
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| int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port);
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| int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port);
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| 
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| enum xenbus_state xenbus_read_driver_state(const char *path);
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| 
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| __printf(3, 4)
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| void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
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| __printf(3, 4)
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| void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
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| 
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| const char *xenbus_strstate(enum xenbus_state state);
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| int xenbus_dev_is_online(struct xenbus_device *dev);
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| int xenbus_frontend_closed(struct xenbus_device *dev);
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| 
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| extern const struct file_operations xen_xenbus_fops;
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| extern struct xenstore_domain_interface *xen_store_interface;
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| extern int xen_store_evtchn;
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| 
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| #endif /* _XEN_XENBUS_H */
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