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![Aurelien Chartier](/assets/img/avatar_default.png)
If the xenbus frontend is located in a domain running xenstored, the device resume is hanging because it is happening before the process resume. This patch adds extra logic to the resume code to check if we are the domain running xenstored and delay the resume if needed. Signed-off-by: Aurelien Chartier <aurelien.chartier@citrix.com> [Changes in v2: - Instead of bypassing the resume, process it in a workqueue] [Changes in v3: - Add a struct work in xenbus_device to avoid dynamic allocation - Several small code fixes] [Changes in v4: - Use a dedicated workqueue] [Changes in v5: - Move create_workqueue error handling to xenbus_frontend_dev_resume] Acked-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
224 lines
7.7 KiB
C
224 lines
7.7 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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#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/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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/* 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 **vec, unsigned int len);
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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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};
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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 struct xenbus_device_id *ids;
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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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};
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#define DEFINE_XENBUS_DRIVER(var, drvname, methods...) \
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struct xenbus_driver var ## _driver = { \
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.driver.name = drvname + 0 ?: var ## _ids->devicetype, \
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.driver.owner = THIS_MODULE, \
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.ids = var ## _ids, ## methods \
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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 *);
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int __must_check xenbus_register_backend(struct xenbus_driver *);
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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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/* 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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/* Used by xenbus_dev to borrow kernel's store connection. */
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void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
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struct work_struct;
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/* Prepare for domain suspend: then resume or cancel the suspend. */
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void xenbus_suspend(void);
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void xenbus_resume(void);
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void xenbus_probe(struct work_struct *);
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void xenbus_suspend_cancel(void);
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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 **, unsigned int));
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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 **, unsigned int),
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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, unsigned long ring_mfn);
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int xenbus_map_ring_valloc(struct xenbus_device *dev,
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int gnt_ref, void **vaddr);
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int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
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grant_handle_t *handle, void *vaddr);
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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 handle, void *vaddr);
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int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
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int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, 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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#endif /* _XEN_XENBUS_H */
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