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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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060eabe8fb
A driver's 'reclaim_memory' callback can race with 'probe' or 'remove' because it will be called whenever memory pressure is detected. To avoid such race, this commit embeds a spinlock in each 'xenbus_device' and make 'xenbus' to hold the lock while the corresponded callbacks are running. Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: SeongJae Park <sjpark@amazon.de> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
240 lines
8.3 KiB
C
240 lines
8.3 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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#ifndef _XEN_XENBUS_H
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#define _XEN_XENBUS_H
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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 <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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#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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#define INVALID_GRANT_HANDLE (~0U)
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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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/* Path being watched. */
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const char *node;
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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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/* 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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spinlock_t reclaim_lock;
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};
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static inline struct xenbus_device *to_xenbus_device(struct device *dev)
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{
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return container_of(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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/* 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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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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int (*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)(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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static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
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{
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return container_of(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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#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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void xenbus_unregister_driver(struct xenbus_driver *drv);
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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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/* Nil transaction ID. */
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#define XBT_NIL ((struct xenbus_transaction) { 0 })
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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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/* 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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/* 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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/* 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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/* 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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/* 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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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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struct work_struct;
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void xenbus_probe(struct work_struct *);
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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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#define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
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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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void (*callback)(struct xenbus_watch *,
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const char *, const char *));
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__printf(4, 5)
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int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
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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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int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
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int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
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unsigned int nr_pages, 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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int xenbus_map_ring(struct xenbus_device *dev,
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grant_ref_t *gnt_refs, unsigned int nr_grefs,
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grant_handle_t *handles, unsigned long *vaddrs,
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bool *leaked);
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int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
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int xenbus_unmap_ring(struct xenbus_device *dev,
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grant_handle_t *handles, unsigned int nr_handles,
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unsigned long *vaddrs);
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int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
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int xenbus_free_evtchn(struct xenbus_device *dev, int port);
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enum xenbus_state xenbus_read_driver_state(const char *path);
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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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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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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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#endif /* _XEN_XENBUS_H */
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