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672b7763cb
If a driver probe() fails then leave the xenstore state alone. There is no
reason to modify it as the failure may be due to transient resource
allocation issues and hence a subsequent probe() may succeed.
If the driver supports re-binding then only force state to closed during
remove() only in the case when the toolstack may need to clean up. This can
be detected by checking whether the state in xenstore has been set to
closing prior to device removal.
NOTE: Re-bind support is indicated by new boolean in struct xenbus_driver,
which defaults to false. Subsequent patches will add support to
some backend drivers.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
238 lines
8.2 KiB
C
238 lines
8.2 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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};
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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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};
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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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