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![Juergen Gross](/assets/img/avatar_default.png)
When booting the xenbus driver will wait for PV devices to have connected to their backends before continuing. The timeout is different between essential and non-essential devices. Non-essential devices are identified by their nodenames directly in the xenbus driver, which requires to update this list in case a new device type being non-essential is added (this was missed for several types in the past). In order to avoid this problem, add a "not_essential" flag to struct xenbus_driver which can be set to "true" by the respective frontend. Set this flag for the frontends currently regarded to be not essential (vkbs and vfb) and use it for testing in the xenbus driver. Signed-off-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20211022064800.14978-2-jgross@suse.com Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
252 lines
8.7 KiB
C
252 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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#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 <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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#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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/* 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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unsigned int nr_pending;
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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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/* 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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struct semaphore reclaim_sem;
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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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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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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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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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#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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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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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_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
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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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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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