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    Subject[patch 22/29] xen: Add the Xenbus sysfs and virtual device hotplug driver.
    This communicates with the machine control software via a registry
    residing in a controlling virtual machine. This allows dynamic
    creation, destruction and modification of virtual device
    configurations (network devices, block devices and CPUS, to name some
    examples).

    [ Greg, would you mind giving this a review? Thanks -J ]

    Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
    Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
    Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
    Signed-off-by: Chris Wright <chrisw@sous-sol.org>
    Cc: Greg KH <greg@kroah.com>
    ---
    drivers/xen/Makefile | 1
    drivers/xen/xenbus/Makefile | 7
    drivers/xen/xenbus/xenbus_client.c | 569 +++++++++++++++++++++
    drivers/xen/xenbus/xenbus_comms.c | 233 ++++++++
    drivers/xen/xenbus/xenbus_comms.h | 46 +
    drivers/xen/xenbus/xenbus_probe.c | 935 ++++++++++++++++++++++++++++++++++++
    drivers/xen/xenbus/xenbus_probe.h | 74 ++
    drivers/xen/xenbus/xenbus_xs.c | 861 +++++++++++++++++++++++++++++++++
    include/asm-i386/xen/hypervisor.h | 1
    include/xen/xenbus.h | 232 ++++++++
    10 files changed, 2959 insertions(+)

    ===================================================================
    --- a/drivers/xen/Makefile
    +++ b/drivers/xen/Makefile
    @@ -1,2 +1,3 @@ obj-y += grant-table.o
    obj-y += grant-table.o
    obj-y += grant-table.o
    +obj-y += xenbus/
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/Makefile
    @@ -0,0 +1,7 @@
    +obj-y += xenbus.o
    +
    +xenbus-objs =
    +xenbus-objs += xenbus_client.o
    +xenbus-objs += xenbus_comms.o
    +xenbus-objs += xenbus_xs.o
    +xenbus-objs += xenbus_probe.o
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/xenbus_client.c
    @@ -0,0 +1,569 @@
    +/******************************************************************************
    + * Client-facing interface for the Xenbus driver. In other words, the
    + * interface between the Xenbus and the device-specific code, be it the
    + * frontend or the backend of that driver.
    + *
    + * Copyright (C) 2005 XenSource Ltd
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#include <linux/types.h>
    +#include <linux/vmalloc.h>
    +#include <asm/xen/hypervisor.h>
    +#include <xen/interface/xen.h>
    +#include <xen/interface/event_channel.h>
    +#include <xen/events.h>
    +#include <xen/grant_table.h>
    +#include <xen/xenbus.h>
    +
    +const char *xenbus_strstate(enum xenbus_state state)
    +{
    + static const char *const name[] = {
    + [ XenbusStateUnknown ] = "Unknown",
    + [ XenbusStateInitialising ] = "Initialising",
    + [ XenbusStateInitWait ] = "InitWait",
    + [ XenbusStateInitialised ] = "Initialised",
    + [ XenbusStateConnected ] = "Connected",
    + [ XenbusStateClosing ] = "Closing",
    + [ XenbusStateClosed ] = "Closed",
    + };
    + return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
    +}
    +EXPORT_SYMBOL_GPL(xenbus_strstate);
    +
    +/**
    + * xenbus_watch_path - register a watch
    + * @dev: xenbus device
    + * @path: path to watch
    + * @watch: watch to register
    + * @callback: callback to register
    + *
    + * Register a @watch on the given path, using the given xenbus_watch structure
    + * for storage, and the given @callback function as the callback. Return 0 on
    + * success, or -errno on error. On success, the given @path will be saved as
    + * @watch->node, and remains the caller's to free. On error, @watch->node will
    + * be NULL, the device will switch to %XenbusStateClosing, and the error will
    + * be saved in the store.
    + */
    +int xenbus_watch_path(struct xenbus_device *dev, const char *path,
    + struct xenbus_watch *watch,
    + void (*callback)(struct xenbus_watch *,
    + const char **, unsigned int))
    +{
    + int err;
    +
    + watch->node = path;
    + watch->callback = callback;
    +
    + err = register_xenbus_watch(watch);
    +
    + if (err) {
    + watch->node = NULL;
    + watch->callback = NULL;
    + xenbus_dev_fatal(dev, err, "adding watch on %s", path);
    + }
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_watch_path);
    +
    +
    +/**
    + * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
    + * @dev: xenbus device
    + * @watch: watch to register
    + * @callback: callback to register
    + * @pathfmt: format of path to watch
    + *
    + * Register a watch on the given @path, using the given xenbus_watch
    + * structure for storage, and the given @callback function as the callback.
    + * Return 0 on success, or -errno on error. On success, the watched path
    + * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
    + * kfree(). On error, watch->node will be NULL, so the caller has nothing to
    + * free, the device will switch to %XenbusStateClosing, and the error will be
    + * saved in the store.
    + */
    +int xenbus_watch_pathfmt(struct xenbus_device *dev,
    + struct xenbus_watch *watch,
    + void (*callback)(struct xenbus_watch *,
    + const char **, unsigned int),
    + const char *pathfmt, ...)
    +{
    + int err;
    + va_list ap;
    + char *path;
    +
    + va_start(ap, pathfmt);
    + path = kvasprintf(GFP_KERNEL, pathfmt, ap);
    + va_end(ap);
    +
    + if (!path) {
    + xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
    + return -ENOMEM;
    + }
    + err = xenbus_watch_path(dev, path, watch, callback);
    +
    + if (err)
    + kfree(path);
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
    +
    +
    +/**
    + * xenbus_switch_state
    + * @dev: xenbus device
    + * @xbt: transaction handle
    + * @state: new state
    + *
    + * Advertise in the store a change of the given driver to the given new_state.
    + * Return 0 on success, or -errno on error. On error, the device will switch
    + * to XenbusStateClosing, and the error will be saved in the store.
    + */
    +int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
    +{
    + /* We check whether the state is currently set to the given value, and
    + if not, then the state is set. We don't want to unconditionally
    + write the given state, because we don't want to fire watches
    + unnecessarily. Furthermore, if the node has gone, we don't write
    + to it, as the device will be tearing down, and we don't want to
    + resurrect that directory.
    +
    + Note that, because of this cached value of our state, this function
    + will not work inside a Xenstore transaction (something it was
    + trying to in the past) because dev->state would not get reset if
    + the transaction was aborted.
    +
    + */
    +
    + int current_state;
    + int err;
    +
    + if (state == dev->state)
    + return 0;
    +
    + err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d",
    + &current_state);
    + if (err != 1)
    + return 0;
    +
    + err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state);
    + if (err) {
    + if (state != XenbusStateClosing) /* Avoid looping */
    + xenbus_dev_fatal(dev, err, "writing new state");
    + return err;
    + }
    +
    + dev->state = state;
    +
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_switch_state);
    +
    +int xenbus_frontend_closed(struct xenbus_device *dev)
    +{
    + xenbus_switch_state(dev, XenbusStateClosed);
    + complete(&dev->down);
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
    +
    +/**
    + * Return the path to the error node for the given device, or NULL on failure.
    + * If the value returned is non-NULL, then it is the caller's to kfree.
    + */
    +static char *error_path(struct xenbus_device *dev)
    +{
    + return kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
    +}
    +
    +
    +static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
    + const char *fmt, va_list ap)
    +{
    + int ret;
    + unsigned int len;
    + char *printf_buffer = NULL;
    + char *path_buffer = NULL;
    +
    +#define PRINTF_BUFFER_SIZE 4096
    + printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
    + if (printf_buffer == NULL)
    + goto fail;
    +
    + len = sprintf(printf_buffer, "%i ", -err);
    + ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
    +
    + BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
    +
    + dev_err(&dev->dev, "%s\n", printf_buffer);
    +
    + path_buffer = error_path(dev);
    +
    + if (path_buffer == NULL) {
    + dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
    + dev->nodename, printf_buffer);
    + goto fail;
    + }
    +
    + if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) {
    + dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
    + dev->nodename, printf_buffer);
    + goto fail;
    + }
    +
    +fail:
    + kfree(printf_buffer);
    + kfree(path_buffer);
    +}
    +
    +
    +/**
    + * xenbus_dev_error
    + * @dev: xenbus device
    + * @err: error to report
    + * @fmt: error message format
    + *
    + * Report the given negative errno into the store, along with the given
    + * formatted message.
    + */
    +void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
    +{
    + va_list ap;
    +
    + va_start(ap, fmt);
    + xenbus_va_dev_error(dev, err, fmt, ap);
    + va_end(ap);
    +}
    +EXPORT_SYMBOL_GPL(xenbus_dev_error);
    +
    +/**
    + * xenbus_dev_fatal
    + * @dev: xenbus device
    + * @err: error to report
    + * @fmt: error message format
    + *
    + * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
    + * xenbus_switch_state(dev, NULL, XenbusStateClosing) to schedule an orderly
    + * closedown of this driver and its peer.
    + */
    +
    +void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
    +{
    + va_list ap;
    +
    + va_start(ap, fmt);
    + xenbus_va_dev_error(dev, err, fmt, ap);
    + va_end(ap);
    +
    + xenbus_switch_state(dev, XenbusStateClosing);
    +}
    +EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
    +
    +/**
    + * xenbus_grant_ring
    + * @dev: xenbus device
    + * @ring_mfn: mfn of ring to grant
    +
    + * Grant access to the given @ring_mfn to the peer of the given device. Return
    + * 0 on success, or -errno on error. On error, the device will switch to
    + * XenbusStateClosing, and the error will be saved in the store.
    + */
    +int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
    +{
    + int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
    + if (err < 0)
    + xenbus_dev_fatal(dev, err, "granting access to ring page");
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_grant_ring);
    +
    +
    +/**
    + * Allocate an event channel for the given xenbus_device, assigning the newly
    + * created local port to *port. Return 0 on success, or -errno on error. On
    + * error, the device will switch to XenbusStateClosing, and the error will be
    + * saved in the store.
    + */
    +int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
    +{
    + struct evtchn_alloc_unbound alloc_unbound;
    + int err;
    +
    + alloc_unbound.dom = DOMID_SELF;
    + alloc_unbound.remote_dom = dev->otherend_id;
    +
    + err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
    + &alloc_unbound);
    + if (err)
    + xenbus_dev_fatal(dev, err, "allocating event channel");
    + else
    + *port = alloc_unbound.port;
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
    +
    +
    +/**
    + * Bind to an existing interdomain event channel in another domain. Returns 0
    + * on success and stores the local port in *port. On error, returns -errno,
    + * switches the device to XenbusStateClosing, and saves the error in XenStore.
    + */
    +int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
    +{
    + struct evtchn_bind_interdomain bind_interdomain;
    + int err;
    +
    + bind_interdomain.remote_dom = dev->otherend_id;
    + bind_interdomain.remote_port = remote_port;
    +
    + err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
    + &bind_interdomain);
    + if (err)
    + xenbus_dev_fatal(dev, err,
    + "binding to event channel %d from domain %d",
    + remote_port, dev->otherend_id);
    + else
    + *port = bind_interdomain.local_port;
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_bind_evtchn);
    +
    +
    +/**
    + * Free an existing event channel. Returns 0 on success or -errno on error.
    + */
    +int xenbus_free_evtchn(struct xenbus_device *dev, int port)
    +{
    + struct evtchn_close close;
    + int err;
    +
    + close.port = port;
    +
    + err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
    + if (err)
    + xenbus_dev_error(dev, err, "freeing event channel %d", port);
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
    +
    +
    +/**
    + * xenbus_map_ring_valloc
    + * @dev: xenbus device
    + * @gnt_ref: grant reference
    + * @vaddr: pointer to address to be filled out by mapping
    + *
    + * Based on Rusty Russell's skeleton driver's map_page.
    + * Map a page of memory into this domain from another domain's grant table.
    + * xenbus_map_ring_valloc allocates a page of virtual address space, maps the
    + * page to that address, and sets *vaddr to that address.
    + * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
    + * or -ENOMEM on error. If an error is returned, device will switch to
    + * XenbusStateClosing and the error message will be saved in XenStore.
    + */
    +int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
    +{
    + struct gnttab_map_grant_ref op = {
    + .flags = GNTMAP_host_map,
    + .ref = gnt_ref,
    + .dom = dev->otherend_id,
    + };
    + struct vm_struct *area;
    +
    + *vaddr = NULL;
    +
    + area = alloc_vm_area(PAGE_SIZE);
    + if (!area)
    + return -ENOMEM;
    +
    + op.host_addr = (unsigned long)area->addr;
    +
    + if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
    + BUG();
    +
    + if (op.status != GNTST_okay) {
    + free_vm_area(area);
    + xenbus_dev_fatal(dev, op.status,
    + "mapping in shared page %d from domain %d",
    + gnt_ref, dev->otherend_id);
    + return op.status;
    + }
    +
    + /* Stuff the handle in an unused field */
    + area->phys_addr = (unsigned long)op.handle;
    +
    + *vaddr = area->addr;
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
    +
    +
    +/**
    + * xenbus_map_ring
    + * @dev: xenbus device
    + * @gnt_ref: grant reference
    + * @handle: pointer to grant handle to be filled
    + * @vaddr: address to be mapped to
    + *
    + * Map a page of memory into this domain from another domain's grant table.
    + * xenbus_map_ring does not allocate the virtual address space (you must do
    + * this yourself!). It only maps in the page to the specified address.
    + * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
    + * or -ENOMEM on error. If an error is returned, device will switch to
    + * XenbusStateClosing and the error message will be saved in XenStore.
    + */
    +int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
    + grant_handle_t *handle, void *vaddr)
    +{
    + struct gnttab_map_grant_ref op = {
    + .host_addr = (unsigned long)vaddr,
    + .flags = GNTMAP_host_map,
    + .ref = gnt_ref,
    + .dom = dev->otherend_id,
    + };
    +
    + if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
    + BUG();
    +
    + if (op.status != GNTST_okay) {
    + xenbus_dev_fatal(dev, op.status,
    + "mapping in shared page %d from domain %d",
    + gnt_ref, dev->otherend_id);
    + } else
    + *handle = op.handle;
    +
    + return op.status;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_map_ring);
    +
    +
    +/**
    + * xenbus_unmap_ring_vfree
    + * @dev: xenbus device
    + * @vaddr: addr to unmap
    + *
    + * Based on Rusty Russell's skeleton driver's unmap_page.
    + * Unmap a page of memory in this domain that was imported from another domain.
    + * Use xenbus_unmap_ring_vfree if you mapped in your memory with
    + * xenbus_map_ring_valloc (it will free the virtual address space).
    + * Returns 0 on success and returns GNTST_* on error
    + * (see xen/include/interface/grant_table.h).
    + */
    +int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
    +{
    + struct vm_struct *area;
    + struct gnttab_unmap_grant_ref op = {
    + .host_addr = (unsigned long)vaddr,
    + };
    +
    + /* It'd be nice if linux/vmalloc.h provided a find_vm_area(void *addr)
    + * method so that we don't have to muck with vmalloc internals here.
    + * We could force the user to hang on to their struct vm_struct from
    + * xenbus_map_ring_valloc, but these 6 lines considerably simplify
    + * this API.
    + */
    + read_lock(&vmlist_lock);
    + for (area = vmlist; area != NULL; area = area->next) {
    + if (area->addr == vaddr)
    + break;
    + }
    + read_unlock(&vmlist_lock);
    +
    + if (!area) {
    + xenbus_dev_error(dev, -ENOENT,
    + "can't find mapped virtual address %p", vaddr);
    + return GNTST_bad_virt_addr;
    + }
    +
    + op.handle = (grant_handle_t)area->phys_addr;
    +
    + if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
    + BUG();
    +
    + if (op.status == GNTST_okay)
    + free_vm_area(area);
    + else
    + xenbus_dev_error(dev, op.status,
    + "unmapping page at handle %d error %d",
    + (int16_t)area->phys_addr, op.status);
    +
    + return op.status;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
    +
    +
    +/**
    + * xenbus_unmap_ring
    + * @dev: xenbus device
    + * @handle: grant handle
    + * @vaddr: addr to unmap
    + *
    + * Unmap a page of memory in this domain that was imported from another domain.
    + * Returns 0 on success and returns GNTST_* on error
    + * (see xen/include/interface/grant_table.h).
    + */
    +int xenbus_unmap_ring(struct xenbus_device *dev,
    + grant_handle_t handle, void *vaddr)
    +{
    + struct gnttab_unmap_grant_ref op = {
    + .host_addr = (unsigned long)vaddr,
    + .handle = handle,
    + };
    +
    + if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
    + BUG();
    +
    + if (op.status != GNTST_okay)
    + xenbus_dev_error(dev, op.status,
    + "unmapping page at handle %d error %d",
    + handle, op.status);
    +
    + return op.status;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
    +
    +
    +/**
    + * xenbus_read_driver_state
    + * @path: path for driver
    + *
    + * Return the state of the driver rooted at the given store path, or
    + * XenbusStateUnknown if no state can be read.
    + */
    +enum xenbus_state xenbus_read_driver_state(const char *path)
    +{
    + enum xenbus_state result;
    + int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
    + if (err)
    + result = XenbusStateUnknown;
    +
    + return result;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/xenbus_comms.c
    @@ -0,0 +1,233 @@
    +/******************************************************************************
    + * xenbus_comms.c
    + *
    + * Low level code to talks to Xen Store: ringbuffer and event channel.
    + *
    + * Copyright (C) 2005 Rusty Russell, IBM Corporation
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#include <linux/wait.h>
    +#include <linux/interrupt.h>
    +#include <linux/sched.h>
    +#include <linux/err.h>
    +#include <xen/xenbus.h>
    +#include <asm/xen/hypervisor.h>
    +#include <xen/events.h>
    +#include <xen/page.h>
    +#include "xenbus_comms.h"
    +
    +static int xenbus_irq;
    +
    +static DECLARE_WORK(probe_work, xenbus_probe);
    +
    +static DECLARE_WAIT_QUEUE_HEAD(xb_waitq);
    +
    +static irqreturn_t wake_waiting(int irq, void *unused)
    +{
    + if (unlikely(xenstored_ready == 0)) {
    + xenstored_ready = 1;
    + schedule_work(&probe_work);
    + }
    +
    + wake_up(&xb_waitq);
    + return IRQ_HANDLED;
    +}
    +
    +static int check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod)
    +{
    + return ((prod - cons) <= XENSTORE_RING_SIZE);
    +}
    +
    +static void *get_output_chunk(XENSTORE_RING_IDX cons,
    + XENSTORE_RING_IDX prod,
    + char *buf, uint32_t *len)
    +{
    + *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod);
    + if ((XENSTORE_RING_SIZE - (prod - cons)) < *len)
    + *len = XENSTORE_RING_SIZE - (prod - cons);
    + return buf + MASK_XENSTORE_IDX(prod);
    +}
    +
    +static const void *get_input_chunk(XENSTORE_RING_IDX cons,
    + XENSTORE_RING_IDX prod,
    + const char *buf, uint32_t *len)
    +{
    + *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons);
    + if ((prod - cons) < *len)
    + *len = prod - cons;
    + return buf + MASK_XENSTORE_IDX(cons);
    +}
    +
    +/**
    + * xb_write - low level write
    + * @data: buffer to send
    + * @len: length of buffer
    + *
    + * Returns 0 on success, error otherwise.
    + */
    +int xb_write(const void *data, unsigned len)
    +{
    + struct xenstore_domain_interface *intf = xen_store_interface;
    + XENSTORE_RING_IDX cons, prod;
    + int rc;
    +
    + while (len != 0) {
    + void *dst;
    + unsigned int avail;
    +
    + rc = wait_event_interruptible(
    + xb_waitq,
    + (intf->req_prod - intf->req_cons) !=
    + XENSTORE_RING_SIZE);
    + if (rc < 0)
    + return rc;
    +
    + /* Read indexes, then verify. */
    + cons = intf->req_cons;
    + prod = intf->req_prod;
    + if (!check_indexes(cons, prod)) {
    + intf->req_cons = intf->req_prod = 0;
    + return -EIO;
    + }
    +
    + dst = get_output_chunk(cons, prod, intf->req, &avail);
    + if (avail == 0)
    + continue;
    + if (avail > len)
    + avail = len;
    +
    + /* Must write data /after/ reading the consumer index. */
    + mb();
    +
    + memcpy(dst, data, avail);
    + data += avail;
    + len -= avail;
    +
    + /* Other side must not see new producer until data is there. */
    + wmb();
    + intf->req_prod += avail;
    +
    + /* Implies mb(): other side will see the updated producer. */
    + notify_remote_via_evtchn(xen_store_evtchn);
    + }
    +
    + return 0;
    +}
    +
    +int xb_data_to_read(void)
    +{
    + struct xenstore_domain_interface *intf = xen_store_interface;
    + return (intf->rsp_cons != intf->rsp_prod);
    +}
    +
    +int xb_wait_for_data_to_read(void)
    +{
    + return wait_event_interruptible(xb_waitq, xb_data_to_read());
    +}
    +
    +int xb_read(void *data, unsigned len)
    +{
    + struct xenstore_domain_interface *intf = xen_store_interface;
    + XENSTORE_RING_IDX cons, prod;
    + int rc;
    +
    + while (len != 0) {
    + unsigned int avail;
    + const char *src;
    +
    + rc = xb_wait_for_data_to_read();
    + if (rc < 0)
    + return rc;
    +
    + /* Read indexes, then verify. */
    + cons = intf->rsp_cons;
    + prod = intf->rsp_prod;
    + if (!check_indexes(cons, prod)) {
    + intf->rsp_cons = intf->rsp_prod = 0;
    + return -EIO;
    + }
    +
    + src = get_input_chunk(cons, prod, intf->rsp, &avail);
    + if (avail == 0)
    + continue;
    + if (avail > len)
    + avail = len;
    +
    + /* Must read data /after/ reading the producer index. */
    + rmb();
    +
    + memcpy(data, src, avail);
    + data += avail;
    + len -= avail;
    +
    + /* Other side must not see free space until we've copied out */
    + mb();
    + intf->rsp_cons += avail;
    +
    + pr_debug("Finished read of %i bytes (%i to go)\n", avail, len);
    +
    + /* Implies mb(): other side will see the updated consumer. */
    + notify_remote_via_evtchn(xen_store_evtchn);
    + }
    +
    + return 0;
    +}
    +
    +/**
    + * xb_init_comms - Set up interrupt handler off store event channel.
    + */
    +int xb_init_comms(void)
    +{
    + struct xenstore_domain_interface *intf = xen_store_interface;
    + int err;
    +
    + if (intf->req_prod != intf->req_cons)
    + printk(KERN_ERR "XENBUS request ring is not quiescent "
    + "(%08x:%08x)!\n", intf->req_cons, intf->req_prod);
    +
    + if (intf->rsp_prod != intf->rsp_cons) {
    + printk(KERN_WARNING "XENBUS response ring is not quiescent "
    + "(%08x:%08x): fixing up\n",
    + intf->rsp_cons, intf->rsp_prod);
    + intf->rsp_cons = intf->rsp_prod;
    + }
    +
    + if (xenbus_irq)
    + unbind_from_irqhandler(xenbus_irq, &xb_waitq);
    +
    + err = bind_evtchn_to_irqhandler(
    + xen_store_evtchn, wake_waiting,
    + 0, "xenbus", &xb_waitq);
    + if (err <= 0) {
    + printk(KERN_ERR "XENBUS request irq failed %i\n", err);
    + return err;
    + }
    +
    + xenbus_irq = err;
    +
    + return 0;
    +}
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/xenbus_comms.h
    @@ -0,0 +1,46 @@
    +/*
    + * Private include for xenbus communications.
    + *
    + * Copyright (C) 2005 Rusty Russell, IBM Corporation
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#ifndef _XENBUS_COMMS_H
    +#define _XENBUS_COMMS_H
    +
    +int xs_init(void);
    +int xb_init_comms(void);
    +
    +/* Low level routines. */
    +int xb_write(const void *data, unsigned len);
    +int xb_read(void *data, unsigned len);
    +int xb_data_to_read(void);
    +int xb_wait_for_data_to_read(void);
    +int xs_input_avail(void);
    +extern struct xenstore_domain_interface *xen_store_interface;
    +extern int xen_store_evtchn;
    +
    +#endif /* _XENBUS_COMMS_H */
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/xenbus_probe.c
    @@ -0,0 +1,935 @@
    +/******************************************************************************
    + * Talks to Xen Store to figure out what devices we have.
    + *
    + * Copyright (C) 2005 Rusty Russell, IBM Corporation
    + * Copyright (C) 2005 Mike Wray, Hewlett-Packard
    + * Copyright (C) 2005, 2006 XenSource Ltd
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#define DPRINTK(fmt, args...) \
    + pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
    + __func__, __LINE__, ##args)
    +
    +#include <linux/kernel.h>
    +#include <linux/err.h>
    +#include <linux/string.h>
    +#include <linux/ctype.h>
    +#include <linux/fcntl.h>
    +#include <linux/mm.h>
    +#include <linux/notifier.h>
    +#include <linux/kthread.h>
    +#include <linux/mutex.h>
    +
    +#include <asm/io.h>
    +#include <asm/page.h>
    +#include <asm/pgtable.h>
    +#include <asm/xen/hypervisor.h>
    +#include <xen/xenbus.h>
    +#include <xen/events.h>
    +#include <xen/page.h>
    +
    +#include "xenbus_comms.h"
    +#include "xenbus_probe.h"
    +
    +int xen_store_evtchn;
    +struct xenstore_domain_interface *xen_store_interface;
    +static unsigned long xen_store_mfn;
    +
    +static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
    +
    +static void wait_for_devices(struct xenbus_driver *xendrv);
    +
    +static int xenbus_probe_frontend(const char *type, const char *name);
    +
    +static void xenbus_dev_shutdown(struct device *_dev);
    +
    +/* If something in array of ids matches this device, return it. */
    +static const struct xenbus_device_id *
    +match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
    +{
    + for (; *arr->devicetype != '\0'; arr++) {
    + if (!strcmp(arr->devicetype, dev->devicetype))
    + return arr;
    + }
    + return NULL;
    +}
    +
    +int xenbus_match(struct device *_dev, struct device_driver *_drv)
    +{
    + struct xenbus_driver *drv = to_xenbus_driver(_drv);
    +
    + if (!drv->ids)
    + return 0;
    +
    + return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
    +}
    +
    +/* device/<type>/<id> => <type>-<id> */
    +static int frontend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename)
    +{
    + nodename = strchr(nodename, '/');
    + if (!nodename || strlen(nodename + 1) >= BUS_ID_SIZE) {
    + printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
    + return -EINVAL;
    + }
    +
    + strlcpy(bus_id, nodename + 1, BUS_ID_SIZE);
    + if (!strchr(bus_id, '/')) {
    + printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
    + return -EINVAL;
    + }
    + *strchr(bus_id, '/') = '-';
    + return 0;
    +}
    +
    +
    +static void free_otherend_details(struct xenbus_device *dev)
    +{
    + kfree(dev->otherend);
    + dev->otherend = NULL;
    +}
    +
    +
    +static void free_otherend_watch(struct xenbus_device *dev)
    +{
    + if (dev->otherend_watch.node) {
    + unregister_xenbus_watch(&dev->otherend_watch);
    + kfree(dev->otherend_watch.node);
    + dev->otherend_watch.node = NULL;
    + }
    +}
    +
    +
    +int read_otherend_details(struct xenbus_device *xendev,
    + char *id_node, char *path_node)
    +{
    + int err = xenbus_gather(XBT_NIL, xendev->nodename,
    + id_node, "%i", &xendev->otherend_id,
    + path_node, NULL, &xendev->otherend,
    + NULL);
    + if (err) {
    + xenbus_dev_fatal(xendev, err,
    + "reading other end details from %s",
    + xendev->nodename);
    + return err;
    + }
    + if (strlen(xendev->otherend) == 0 ||
    + !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
    + xenbus_dev_fatal(xendev, -ENOENT,
    + "unable to read other end from %s. "
    + "missing or inaccessible.",
    + xendev->nodename);
    + free_otherend_details(xendev);
    + return -ENOENT;
    + }
    +
    + return 0;
    +}
    +
    +
    +static int read_backend_details(struct xenbus_device *xendev)
    +{
    + return read_otherend_details(xendev, "backend-id", "backend");
    +}
    +
    +
    +/* Bus type for frontend drivers. */
    +static struct xen_bus_type xenbus_frontend = {
    + .root = "device",
    + .levels = 2, /* device/type/<id> */
    + .get_bus_id = frontend_bus_id,
    + .probe = xenbus_probe_frontend,
    + .bus = {
    + .name = "xen",
    + .match = xenbus_match,
    + .probe = xenbus_dev_probe,
    + .remove = xenbus_dev_remove,
    + .shutdown = xenbus_dev_shutdown,
    + },
    +};
    +
    +static void otherend_changed(struct xenbus_watch *watch,
    + const char **vec, unsigned int len)
    +{
    + struct xenbus_device *dev =
    + container_of(watch, struct xenbus_device, otherend_watch);
    + struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
    + enum xenbus_state state;
    +
    + /* Protect us against watches firing on old details when the otherend
    + details change, say immediately after a resume. */
    + if (!dev->otherend ||
    + strncmp(dev->otherend, vec[XS_WATCH_PATH],
    + strlen(dev->otherend))) {
    + dev_dbg(&dev->dev, "Ignoring watch at %s", vec[XS_WATCH_PATH]);
    + return;
    + }
    +
    + state = xenbus_read_driver_state(dev->otherend);
    +
    + dev_dbg(&dev->dev, "state is %d, (%s), %s, %s",
    + state, xenbus_strstate(state), dev->otherend_watch.node,
    + vec[XS_WATCH_PATH]);
    +
    + /*
    + * Ignore xenbus transitions during shutdown. This prevents us doing
    + * work that can fail e.g., when the rootfs is gone.
    + */
    + if (system_state > SYSTEM_RUNNING) {
    + struct xen_bus_type *bus = bus;
    + bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
    + /* If we're frontend, drive the state machine to Closed. */
    + /* This should cause the backend to release our resources. */
    + if ((bus == &xenbus_frontend) && (state == XenbusStateClosing))
    + xenbus_frontend_closed(dev);
    + return;
    + }
    +
    + if (drv->otherend_changed)
    + drv->otherend_changed(dev, state);
    +}
    +
    +
    +static int talk_to_otherend(struct xenbus_device *dev)
    +{
    + struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
    +
    + free_otherend_watch(dev);
    + free_otherend_details(dev);
    +
    + return drv->read_otherend_details(dev);
    +}
    +
    +
    +static int watch_otherend(struct xenbus_device *dev)
    +{
    + return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed,
    + "%s/%s", dev->otherend, "state");
    +}
    +
    +
    +int xenbus_dev_probe(struct device *_dev)
    +{
    + struct xenbus_device *dev = to_xenbus_device(_dev);
    + struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
    + const struct xenbus_device_id *id;
    + int err;
    +
    + DPRINTK("%s", dev->nodename);
    +
    + if (!drv->probe) {
    + err = -ENODEV;
    + goto fail;
    + }
    +
    + id = match_device(drv->ids, dev);
    + if (!id) {
    + err = -ENODEV;
    + goto fail;
    + }
    +
    + err = talk_to_otherend(dev);
    + if (err) {
    + dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
    + dev->nodename);
    + return err;
    + }
    +
    + err = drv->probe(dev, id);
    + if (err)
    + goto fail;
    +
    + err = watch_otherend(dev);
    + if (err) {
    + dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
    + dev->nodename);
    + return err;
    + }
    +
    + return 0;
    +fail:
    + xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
    + xenbus_switch_state(dev, XenbusStateClosed);
    + return -ENODEV;
    +}
    +
    +int xenbus_dev_remove(struct device *_dev)
    +{
    + struct xenbus_device *dev = to_xenbus_device(_dev);
    + struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
    +
    + DPRINTK("%s", dev->nodename);
    +
    + free_otherend_watch(dev);
    + free_otherend_details(dev);
    +
    + if (drv->remove)
    + drv->remove(dev);
    +
    + xenbus_switch_state(dev, XenbusStateClosed);
    + return 0;
    +}
    +
    +static void xenbus_dev_shutdown(struct device *_dev)
    +{
    + struct xenbus_device *dev = to_xenbus_device(_dev);
    + unsigned long timeout = 5*HZ;
    +
    + DPRINTK("%s", dev->nodename);
    +
    + get_device(&dev->dev);
    + if (dev->state != XenbusStateConnected) {
    + printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
    + dev->nodename, xenbus_strstate(dev->state));
    + goto out;
    + }
    + xenbus_switch_state(dev, XenbusStateClosing);
    + timeout = wait_for_completion_timeout(&dev->down, timeout);
    + if (!timeout)
    + printk(KERN_INFO "%s: %s timeout closing device\n",
    + __func__, dev->nodename);
    + out:
    + put_device(&dev->dev);
    +}
    +
    +int xenbus_register_driver_common(struct xenbus_driver *drv,
    + struct xen_bus_type *bus,
    + struct module *owner,
    + const char *mod_name)
    +{
    + drv->driver.name = drv->name;
    + drv->driver.bus = &bus->bus;
    + drv->driver.owner = owner;
    + drv->driver.mod_name = mod_name;
    +
    + return driver_register(&drv->driver);
    +}
    +
    +int __xenbus_register_frontend(struct xenbus_driver *drv,
    + struct module *owner, const char *mod_name)
    +{
    + int ret;
    +
    + drv->read_otherend_details = read_backend_details;
    +
    + ret = xenbus_register_driver_common(drv, &xenbus_frontend,
    + owner, mod_name);
    + if (ret)
    + return ret;
    +
    + /* If this driver is loaded as a module wait for devices to attach. */
    + wait_for_devices(drv);
    +
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
    +
    +void xenbus_unregister_driver(struct xenbus_driver *drv)
    +{
    + driver_unregister(&drv->driver);
    +}
    +EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
    +
    +struct xb_find_info
    +{
    + struct xenbus_device *dev;
    + const char *nodename;
    +};
    +
    +static int cmp_dev(struct device *dev, void *data)
    +{
    + struct xenbus_device *xendev = to_xenbus_device(dev);
    + struct xb_find_info *info = data;
    +
    + if (!strcmp(xendev->nodename, info->nodename)) {
    + info->dev = xendev;
    + get_device(dev);
    + return 1;
    + }
    + return 0;
    +}
    +
    +struct xenbus_device *xenbus_device_find(const char *nodename,
    + struct bus_type *bus)
    +{
    + struct xb_find_info info = { .dev = NULL, .nodename = nodename };
    +
    + bus_for_each_dev(bus, NULL, &info, cmp_dev);
    + return info.dev;
    +}
    +
    +static int cleanup_dev(struct device *dev, void *data)
    +{
    + struct xenbus_device *xendev = to_xenbus_device(dev);
    + struct xb_find_info *info = data;
    + int len = strlen(info->nodename);
    +
    + DPRINTK("%s", info->nodename);
    +
    + /* Match the info->nodename path, or any subdirectory of that path. */
    + if (strncmp(xendev->nodename, info->nodename, len))
    + return 0;
    +
    + /* If the node name is longer, ensure it really is a subdirectory. */
    + if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
    + return 0;
    +
    + info->dev = xendev;
    + get_device(dev);
    + return 1;
    +}
    +
    +static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
    +{
    + struct xb_find_info info = { .nodename = path };
    +
    + do {
    + info.dev = NULL;
    + bus_for_each_dev(bus, NULL, &info, cleanup_dev);
    + if (info.dev) {
    + device_unregister(&info.dev->dev);
    + put_device(&info.dev->dev);
    + }
    + } while (info.dev);
    +}
    +
    +static void xenbus_dev_release(struct device *dev)
    +{
    + if (dev)
    + kfree(to_xenbus_device(dev));
    +}
    +
    +static ssize_t xendev_show_nodename(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
    +}
    +DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
    +
    +static ssize_t xendev_show_devtype(struct device *dev,
    + struct device_attribute *attr, char *buf)
    +{
    + return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
    +}
    +DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
    +
    +
    +int xenbus_probe_node(struct xen_bus_type *bus,
    + const char *type,
    + const char *nodename)
    +{
    + int err;
    + struct xenbus_device *xendev;
    + size_t stringlen;
    + char *tmpstring;
    +
    + enum xenbus_state state = xenbus_read_driver_state(nodename);
    +
    + if (state != XenbusStateInitialising) {
    + /* Device is not new, so ignore it. This can happen if a
    + device is going away after switching to Closed. */
    + return 0;
    + }
    +
    + stringlen = strlen(nodename) + 1 + strlen(type) + 1;
    + xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
    + if (!xendev)
    + return -ENOMEM;
    +
    + xendev->state = XenbusStateInitialising;
    +
    + /* Copy the strings into the extra space. */
    +
    + tmpstring = (char *)(xendev + 1);
    + strcpy(tmpstring, nodename);
    + xendev->nodename = tmpstring;
    +
    + tmpstring += strlen(tmpstring) + 1;
    + strcpy(tmpstring, type);
    + xendev->devicetype = tmpstring;
    + init_completion(&xendev->down);
    +
    + xendev->dev.bus = &bus->bus;
    + xendev->dev.release = xenbus_dev_release;
    +
    + err = bus->get_bus_id(xendev->dev.bus_id, xendev->nodename);
    + if (err)
    + goto fail;
    +
    + /* Register with generic device framework. */
    + err = device_register(&xendev->dev);
    + if (err)
    + goto fail;
    +
    + err = device_create_file(&xendev->dev, &dev_attr_nodename);
    + if (err)
    + goto fail_unregister;
    +
    + err = device_create_file(&xendev->dev, &dev_attr_devtype);
    + if (err)
    + goto fail_remove_file;
    +
    + return 0;
    +fail_remove_file:
    + device_remove_file(&xendev->dev, &dev_attr_nodename);
    +fail_unregister:
    + device_unregister(&xendev->dev);
    +fail:
    + kfree(xendev);
    + return err;
    +}
    +
    +/* device/<typename>/<name> */
    +static int xenbus_probe_frontend(const char *type, const char *name)
    +{
    + char *nodename;
    + int err;
    +
    + nodename = kasprintf(GFP_KERNEL, "%s/%s/%s",
    + xenbus_frontend.root, type, name);
    + if (!nodename)
    + return -ENOMEM;
    +
    + DPRINTK("%s", nodename);
    +
    + err = xenbus_probe_node(&xenbus_frontend, type, nodename);
    + kfree(nodename);
    + return err;
    +}
    +
    +static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
    +{
    + int err = 0;
    + char **dir;
    + unsigned int dir_n = 0;
    + int i;
    +
    + dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
    + if (IS_ERR(dir))
    + return PTR_ERR(dir);
    +
    + for (i = 0; i < dir_n; i++) {
    + err = bus->probe(type, dir[i]);
    + if (err)
    + break;
    + }
    + kfree(dir);
    + return err;
    +}
    +
    +int xenbus_probe_devices(struct xen_bus_type *bus)
    +{
    + int err = 0;
    + char **dir;
    + unsigned int i, dir_n;
    +
    + dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
    + if (IS_ERR(dir))
    + return PTR_ERR(dir);
    +
    + for (i = 0; i < dir_n; i++) {
    + err = xenbus_probe_device_type(bus, dir[i]);
    + if (err)
    + break;
    + }
    + kfree(dir);
    + return err;
    +}
    +
    +static unsigned int char_count(const char *str, char c)
    +{
    + unsigned int i, ret = 0;
    +
    + for (i = 0; str[i]; i++)
    + if (str[i] == c)
    + ret++;
    + return ret;
    +}
    +
    +static int strsep_len(const char *str, char c, unsigned int len)
    +{
    + unsigned int i;
    +
    + for (i = 0; str[i]; i++)
    + if (str[i] == c) {
    + if (len == 0)
    + return i;
    + len--;
    + }
    + return (len == 0) ? i : -ERANGE;
    +}
    +
    +void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
    +{
    + int exists, rootlen;
    + struct xenbus_device *dev;
    + char type[BUS_ID_SIZE];
    + const char *p, *root;
    +
    + if (char_count(node, '/') < 2)
    + return;
    +
    + exists = xenbus_exists(XBT_NIL, node, "");
    + if (!exists) {
    + xenbus_cleanup_devices(node, &bus->bus);
    + return;
    + }
    +
    + /* backend/<type>/... or device/<type>/... */
    + p = strchr(node, '/') + 1;
    + snprintf(type, BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
    + type[BUS_ID_SIZE-1] = '\0';
    +
    + rootlen = strsep_len(node, '/', bus->levels);
    + if (rootlen < 0)
    + return;
    + root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
    + if (!root)
    + return;
    +
    + dev = xenbus_device_find(root, &bus->bus);
    + if (!dev)
    + xenbus_probe_node(bus, type, root);
    + else
    + put_device(&dev->dev);
    +
    + kfree(root);
    +}
    +
    +static void frontend_changed(struct xenbus_watch *watch,
    + const char **vec, unsigned int len)
    +{
    + DPRINTK("");
    +
    + xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
    +}
    +
    +/* We watch for devices appearing and vanishing. */
    +static struct xenbus_watch fe_watch = {
    + .node = "device",
    + .callback = frontend_changed,
    +};
    +
    +static int suspend_dev(struct device *dev, void *data)
    +{
    + int err = 0;
    + struct xenbus_driver *drv;
    + struct xenbus_device *xdev;
    +
    + DPRINTK("");
    +
    + if (dev->driver == NULL)
    + return 0;
    + drv = to_xenbus_driver(dev->driver);
    + xdev = container_of(dev, struct xenbus_device, dev);
    + if (drv->suspend)
    + err = drv->suspend(xdev);
    + if (err)
    + printk(KERN_WARNING
    + "xenbus: suspend %s failed: %i\n", dev->bus_id, err);
    + return 0;
    +}
    +
    +static int suspend_cancel_dev(struct device *dev, void *data)
    +{
    + int err = 0;
    + struct xenbus_driver *drv;
    + struct xenbus_device *xdev;
    +
    + DPRINTK("");
    +
    + if (dev->driver == NULL)
    + return 0;
    + drv = to_xenbus_driver(dev->driver);
    + xdev = container_of(dev, struct xenbus_device, dev);
    + if (drv->suspend_cancel)
    + err = drv->suspend_cancel(xdev);
    + if (err)
    + printk(KERN_WARNING
    + "xenbus: suspend_cancel %s failed: %i\n",
    + dev->bus_id, err);
    + return 0;
    +}
    +
    +static int resume_dev(struct device *dev, void *data)
    +{
    + int err;
    + struct xenbus_driver *drv;
    + struct xenbus_device *xdev;
    +
    + DPRINTK("");
    +
    + if (dev->driver == NULL)
    + return 0;
    +
    + drv = to_xenbus_driver(dev->driver);
    + xdev = container_of(dev, struct xenbus_device, dev);
    +
    + err = talk_to_otherend(xdev);
    + if (err) {
    + printk(KERN_WARNING
    + "xenbus: resume (talk_to_otherend) %s failed: %i\n",
    + dev->bus_id, err);
    + return err;
    + }
    +
    + xdev->state = XenbusStateInitialising;
    +
    + if (drv->resume) {
    + err = drv->resume(xdev);
    + if (err) {
    + printk(KERN_WARNING
    + "xenbus: resume %s failed: %i\n",
    + dev->bus_id, err);
    + return err;
    + }
    + }
    +
    + err = watch_otherend(xdev);
    + if (err) {
    + printk(KERN_WARNING
    + "xenbus_probe: resume (watch_otherend) %s failed: "
    + "%d.\n", dev->bus_id, err);
    + return err;
    + }
    +
    + return 0;
    +}
    +
    +void xenbus_suspend(void)
    +{
    + DPRINTK("");
    +
    + bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_dev);
    + xenbus_backend_suspend(suspend_dev);
    + xs_suspend();
    +}
    +EXPORT_SYMBOL_GPL(xenbus_suspend);
    +
    +void xenbus_resume(void)
    +{
    + xb_init_comms();
    + xs_resume();
    + bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, resume_dev);
    + xenbus_backend_resume(resume_dev);
    +}
    +EXPORT_SYMBOL_GPL(xenbus_resume);
    +
    +void xenbus_suspend_cancel(void)
    +{
    + xs_suspend_cancel();
    + bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_cancel_dev);
    + xenbus_backend_resume(suspend_cancel_dev);
    +}
    +EXPORT_SYMBOL_GPL(xenbus_suspend_cancel);
    +
    +/* A flag to determine if xenstored is 'ready' (i.e. has started) */
    +int xenstored_ready = 0;
    +
    +
    +int register_xenstore_notifier(struct notifier_block *nb)
    +{
    + int ret = 0;
    +
    + if (xenstored_ready > 0)
    + ret = nb->notifier_call(nb, 0, NULL);
    + else
    + blocking_notifier_chain_register(&xenstore_chain, nb);
    +
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(register_xenstore_notifier);
    +
    +void unregister_xenstore_notifier(struct notifier_block *nb)
    +{
    + blocking_notifier_chain_unregister(&xenstore_chain, nb);
    +}
    +EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
    +
    +void xenbus_probe(struct work_struct *unused)
    +{
    + BUG_ON((xenstored_ready <= 0));
    +
    + /* Enumerate devices in xenstore and watch for changes. */
    + xenbus_probe_devices(&xenbus_frontend);
    + register_xenbus_watch(&fe_watch);
    + xenbus_backend_probe_and_watch();
    +
    + /* Notify others that xenstore is up */
    + blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
    +}
    +
    +static int __init xenbus_probe_init(void)
    +{
    + int err = 0;
    +
    + DPRINTK("");
    +
    + err = -ENODEV;
    + if (!is_running_on_xen())
    + goto out_error;
    +
    + /* Register ourselves with the kernel bus subsystem */
    + err = bus_register(&xenbus_frontend.bus);
    + if (err)
    + goto out_error;
    +
    + err = xenbus_backend_bus_register();
    + if (err)
    + goto out_unreg_front;
    +
    + /*
    + * Domain0 doesn't have a store_evtchn or store_mfn yet.
    + */
    + if (is_initial_xendomain()) {
    + /* dom0 not yet supported */
    + } else {
    + xenstored_ready = 1;
    + xen_store_evtchn = xen_start_info->store_evtchn;
    + xen_store_mfn = xen_start_info->store_mfn;
    + }
    + xen_store_interface = mfn_to_virt(xen_store_mfn);
    +
    + /* Initialize the interface to xenstore. */
    + err = xs_init();
    + if (err) {
    + printk(KERN_WARNING
    + "XENBUS: Error initializing xenstore comms: %i\n", err);
    + goto out_unreg_back;
    + }
    +
    + if (!is_initial_xendomain())
    + xenbus_probe(NULL);
    +
    + return 0;
    +
    + out_unreg_back:
    + xenbus_backend_bus_unregister();
    +
    + out_unreg_front:
    + bus_unregister(&xenbus_frontend.bus);
    +
    + out_error:
    + return err;
    +}
    +
    +postcore_initcall(xenbus_probe_init);
    +
    +MODULE_LICENSE("GPL");
    +
    +static int is_disconnected_device(struct device *dev, void *data)
    +{
    + struct xenbus_device *xendev = to_xenbus_device(dev);
    + struct device_driver *drv = data;
    +
    + /*
    + * A device with no driver will never connect. We care only about
    + * devices which should currently be in the process of connecting.
    + */
    + if (!dev->driver)
    + return 0;
    +
    + /* Is this search limited to a particular driver? */
    + if (drv && (dev->driver != drv))
    + return 0;
    +
    + return (xendev->state != XenbusStateConnected);
    +}
    +
    +static int exists_disconnected_device(struct device_driver *drv)
    +{
    + return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
    + is_disconnected_device);
    +}
    +
    +static int print_device_status(struct device *dev, void *data)
    +{
    + struct xenbus_device *xendev = to_xenbus_device(dev);
    + struct device_driver *drv = data;
    +
    + /* Is this operation limited to a particular driver? */
    + if (drv && (dev->driver != drv))
    + return 0;
    +
    + if (!dev->driver) {
    + /* Information only: is this too noisy? */
    + printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
    + xendev->nodename);
    + } else if (xendev->state != XenbusStateConnected) {
    + printk(KERN_WARNING "XENBUS: Timeout connecting "
    + "to device: %s (state %d)\n",
    + xendev->nodename, xendev->state);
    + }
    +
    + return 0;
    +}
    +
    +/* We only wait for device setup after most initcalls have run. */
    +static int ready_to_wait_for_devices;
    +
    +/*
    + * On a 10 second timeout, wait for all devices currently configured. We need
    + * to do this to guarantee that the filesystems and / or network devices
    + * needed for boot are available, before we can allow the boot to proceed.
    + *
    + * This needs to be on a late_initcall, to happen after the frontend device
    + * drivers have been initialised, but before the root fs is mounted.
    + *
    + * A possible improvement here would be to have the tools add a per-device
    + * flag to the store entry, indicating whether it is needed at boot time.
    + * This would allow people who knew what they were doing to accelerate their
    + * boot slightly, but of course needs tools or manual intervention to set up
    + * those flags correctly.
    + */
    +static void wait_for_devices(struct xenbus_driver *xendrv)
    +{
    + unsigned long timeout = jiffies + 10*HZ;
    + struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
    +
    + if (!ready_to_wait_for_devices || !is_running_on_xen())
    + return;
    +
    + while (exists_disconnected_device(drv)) {
    + if (time_after(jiffies, timeout))
    + break;
    + schedule_timeout_interruptible(HZ/10);
    + }
    +
    + bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
    + print_device_status);
    +}
    +
    +#ifndef MODULE
    +static int __init boot_wait_for_devices(void)
    +{
    + ready_to_wait_for_devices = 1;
    + wait_for_devices(NULL);
    + return 0;
    +}
    +
    +late_initcall(boot_wait_for_devices);
    +#endif
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/xenbus_probe.h
    @@ -0,0 +1,74 @@
    +/******************************************************************************
    + * xenbus_probe.h
    + *
    + * Talks to Xen Store to figure out what devices we have.
    + *
    + * Copyright (C) 2005 Rusty Russell, IBM Corporation
    + * Copyright (C) 2005 XenSource Ltd.
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#ifndef _XENBUS_PROBE_H
    +#define _XENBUS_PROBE_H
    +
    +#ifdef CONFIG_XEN_BACKEND
    +extern void xenbus_backend_suspend(int (*fn)(struct device *, void *));
    +extern void xenbus_backend_resume(int (*fn)(struct device *, void *));
    +extern void xenbus_backend_probe_and_watch(void);
    +extern int xenbus_backend_bus_register(void);
    +extern void xenbus_backend_bus_unregister(void);
    +#else
    +static inline void xenbus_backend_suspend(int (*fn)(struct device *, void *)) {}
    +static inline void xenbus_backend_resume(int (*fn)(struct device *, void *)) {}
    +static inline void xenbus_backend_probe_and_watch(void) {}
    +static inline int xenbus_backend_bus_register(void) {return 0;}
    +static inline void xenbus_backend_bus_unregister(void) {}
    +#endif
    +
    +struct xen_bus_type
    +{
    + char *root;
    + unsigned int levels;
    + int (*get_bus_id)(char bus_id[BUS_ID_SIZE], const char *nodename);
    + int (*probe)(const char *type, const char *dir);
    + struct bus_type bus;
    +};
    +
    +extern int xenbus_match(struct device *_dev, struct device_driver *_drv);
    +extern int xenbus_dev_probe(struct device *_dev);
    +extern int xenbus_dev_remove(struct device *_dev);
    +extern int xenbus_register_driver_common(struct xenbus_driver *drv,
    + struct xen_bus_type *bus,
    + struct module *owner,
    + const char *mod_name);
    +extern int xenbus_probe_node(struct xen_bus_type *bus,
    + const char *type,
    + const char *nodename);
    +extern int xenbus_probe_devices(struct xen_bus_type *bus);
    +
    +extern void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);
    +
    +#endif
    ===================================================================
    --- /dev/null
    +++ b/drivers/xen/xenbus/xenbus_xs.c
    @@ -0,0 +1,861 @@
    +/******************************************************************************
    + * xenbus_xs.c
    + *
    + * This is the kernel equivalent of the "xs" library. We don't need everything
    + * and we use xenbus_comms for communication.
    + *
    + * Copyright (C) 2005 Rusty Russell, IBM Corporation
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#include <linux/unistd.h>
    +#include <linux/errno.h>
    +#include <linux/types.h>
    +#include <linux/uio.h>
    +#include <linux/kernel.h>
    +#include <linux/string.h>
    +#include <linux/err.h>
    +#include <linux/slab.h>
    +#include <linux/fcntl.h>
    +#include <linux/kthread.h>
    +#include <linux/rwsem.h>
    +#include <linux/module.h>
    +#include <linux/mutex.h>
    +#include <xen/xenbus.h>
    +#include "xenbus_comms.h"
    +
    +struct xs_stored_msg {
    + struct list_head list;
    +
    + struct xsd_sockmsg hdr;
    +
    + union {
    + /* Queued replies. */
    + struct {
    + char *body;
    + } reply;
    +
    + /* Queued watch events. */
    + struct {
    + struct xenbus_watch *handle;
    + char **vec;
    + unsigned int vec_size;
    + } watch;
    + } u;
    +};
    +
    +struct xs_handle {
    + /* A list of replies. Currently only one will ever be outstanding. */
    + struct list_head reply_list;
    + spinlock_t reply_lock;
    + wait_queue_head_t reply_waitq;
    +
    + /*
    + * Mutex ordering: transaction_mutex -> watch_mutex -> request_mutex.
    + * response_mutex is never taken simultaneously with the other three.
    + */
    +
    + /* One request at a time. */
    + struct mutex request_mutex;
    +
    + /* Protect xenbus reader thread against save/restore. */
    + struct mutex response_mutex;
    +
    + /* Protect transactions against save/restore. */
    + struct rw_semaphore transaction_mutex;
    +
    + /* Protect watch (de)register against save/restore. */
    + struct rw_semaphore watch_mutex;
    +};
    +
    +static struct xs_handle xs_state;
    +
    +/* List of registered watches, and a lock to protect it. */
    +static LIST_HEAD(watches);
    +static DEFINE_SPINLOCK(watches_lock);
    +
    +/* List of pending watch callback events, and a lock to protect it. */
    +static LIST_HEAD(watch_events);
    +static DEFINE_SPINLOCK(watch_events_lock);
    +
    +/*
    + * Details of the xenwatch callback kernel thread. The thread waits on the
    + * watch_events_waitq for work to do (queued on watch_events list). When it
    + * wakes up it acquires the xenwatch_mutex before reading the list and
    + * carrying out work.
    + */
    +static pid_t xenwatch_pid;
    +static DEFINE_MUTEX(xenwatch_mutex);
    +static DECLARE_WAIT_QUEUE_HEAD(watch_events_waitq);
    +
    +static int get_error(const char *errorstring)
    +{
    + unsigned int i;
    +
    + for (i = 0; strcmp(errorstring, xsd_errors[i].errstring) != 0; i++) {
    + if (i == ARRAY_SIZE(xsd_errors) - 1) {
    + printk(KERN_WARNING
    + "XENBUS xen store gave: unknown error %s",
    + errorstring);
    + return EINVAL;
    + }
    + }
    + return xsd_errors[i].errnum;
    +}
    +
    +static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
    +{
    + struct xs_stored_msg *msg;
    + char *body;
    +
    + spin_lock(&xs_state.reply_lock);
    +
    + while (list_empty(&xs_state.reply_list)) {
    + spin_unlock(&xs_state.reply_lock);
    + /* XXX FIXME: Avoid synchronous wait for response here. */
    + wait_event(xs_state.reply_waitq,
    + !list_empty(&xs_state.reply_list));
    + spin_lock(&xs_state.reply_lock);
    + }
    +
    + msg = list_entry(xs_state.reply_list.next,
    + struct xs_stored_msg, list);
    + list_del(&msg->list);
    +
    + spin_unlock(&xs_state.reply_lock);
    +
    + *type = msg->hdr.type;
    + if (len)
    + *len = msg->hdr.len;
    + body = msg->u.reply.body;
    +
    + kfree(msg);
    +
    + return body;
    +}
    +
    +void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
    +{
    + void *ret;
    + struct xsd_sockmsg req_msg = *msg;
    + int err;
    +
    + if (req_msg.type == XS_TRANSACTION_START)
    + down_read(&xs_state.transaction_mutex);
    +
    + mutex_lock(&xs_state.request_mutex);
    +
    + err = xb_write(msg, sizeof(*msg) + msg->len);
    + if (err) {
    + msg->type = XS_ERROR;
    + ret = ERR_PTR(err);
    + } else
    + ret = read_reply(&msg->type, &msg->len);
    +
    + mutex_unlock(&xs_state.request_mutex);
    +
    + if ((msg->type == XS_TRANSACTION_END) ||
    + ((req_msg.type == XS_TRANSACTION_START) &&
    + (msg->type == XS_ERROR)))
    + up_read(&xs_state.transaction_mutex);
    +
    + return ret;
    +}
    +
    +/* Send message to xs, get kmalloc'ed reply. ERR_PTR() on error. */
    +static void *xs_talkv(struct xenbus_transaction t,
    + enum xsd_sockmsg_type type,
    + const struct kvec *iovec,
    + unsigned int num_vecs,
    + unsigned int *len)
    +{
    + struct xsd_sockmsg msg;
    + void *ret = NULL;
    + unsigned int i;
    + int err;
    +
    + msg.tx_id = t.id;
    + msg.req_id = 0;
    + msg.type = type;
    + msg.len = 0;
    + for (i = 0; i < num_vecs; i++)
    + msg.len += iovec[i].iov_len;
    +
    + mutex_lock(&xs_state.request_mutex);
    +
    + err = xb_write(&msg, sizeof(msg));
    + if (err) {
    + mutex_unlock(&xs_state.request_mutex);
    + return ERR_PTR(err);
    + }
    +
    + for (i = 0; i < num_vecs; i++) {
    + err = xb_write(iovec[i].iov_base, iovec[i].iov_len);;
    + if (err) {
    + mutex_unlock(&xs_state.request_mutex);
    + return ERR_PTR(err);
    + }
    + }
    +
    + ret = read_reply(&msg.type, len);
    +
    + mutex_unlock(&xs_state.request_mutex);
    +
    + if (IS_ERR(ret))
    + return ret;
    +
    + if (msg.type == XS_ERROR) {
    + err = get_error(ret);
    + kfree(ret);
    + return ERR_PTR(-err);
    + }
    +
    + if (msg.type != type) {
    + if (printk_ratelimit())
    + printk(KERN_WARNING
    + "XENBUS unexpected type [%d], expected [%d]\n",
    + msg.type, type);
    + kfree(ret);
    + return ERR_PTR(-EINVAL);
    + }
    + return ret;
    +}
    +
    +/* Simplified version of xs_talkv: single message. */
    +static void *xs_single(struct xenbus_transaction t,
    + enum xsd_sockmsg_type type,
    + const char *string,
    + unsigned int *len)
    +{
    + struct kvec iovec;
    +
    + iovec.iov_base = (void *)string;
    + iovec.iov_len = strlen(string) + 1;
    + return xs_talkv(t, type, &iovec, 1, len);
    +}
    +
    +/* Many commands only need an ack, don't care what it says. */
    +static int xs_error(char *reply)
    +{
    + if (IS_ERR(reply))
    + return PTR_ERR(reply);
    + kfree(reply);
    + return 0;
    +}
    +
    +static unsigned int count_strings(const char *strings, unsigned int len)
    +{
    + unsigned int num;
    + const char *p;
    +
    + for (p = strings, num = 0; p < strings + len; p += strlen(p) + 1)
    + num++;
    +
    + return num;
    +}
    +
    +/* Return the path to dir with /name appended. Buffer must be kfree()'ed. */
    +static char *join(const char *dir, const char *name)
    +{
    + char *buffer;
    +
    + if (strlen(name) == 0)
    + buffer = kasprintf(GFP_KERNEL, "%s", dir);
    + else
    + buffer = kasprintf(GFP_KERNEL, "%s/%s", dir, name);
    + return (!buffer) ? ERR_PTR(-ENOMEM) : buffer;
    +}
    +
    +static char **split(char *strings, unsigned int len, unsigned int *num)
    +{
    + char *p, **ret;
    +
    + /* Count the strings. */
    + *num = count_strings(strings, len);
    +
    + /* Transfer to one big alloc for easy freeing. */
    + ret = kmalloc(*num * sizeof(char *) + len, GFP_KERNEL);
    + if (!ret) {
    + kfree(strings);
    + return ERR_PTR(-ENOMEM);
    + }
    + memcpy(&ret[*num], strings, len);
    + kfree(strings);
    +
    + strings = (char *)&ret[*num];
    + for (p = strings, *num = 0; p < strings + len; p += strlen(p) + 1)
    + ret[(*num)++] = p;
    +
    + return ret;
    +}
    +
    +char **xenbus_directory(struct xenbus_transaction t,
    + const char *dir, const char *node, unsigned int *num)
    +{
    + char *strings, *path;
    + unsigned int len;
    +
    + path = join(dir, node);
    + if (IS_ERR(path))
    + return (char **)path;
    +
    + strings = xs_single(t, XS_DIRECTORY, path, &len);
    + kfree(path);
    + if (IS_ERR(strings))
    + return (char **)strings;
    +
    + return split(strings, len, num);
    +}
    +EXPORT_SYMBOL_GPL(xenbus_directory);
    +
    +/* Check if a path exists. Return 1 if it does. */
    +int xenbus_exists(struct xenbus_transaction t,
    + const char *dir, const char *node)
    +{
    + char **d;
    + int dir_n;
    +
    + d = xenbus_directory(t, dir, node, &dir_n);
    + if (IS_ERR(d))
    + return 0;
    + kfree(d);
    + return 1;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_exists);
    +
    +/* Get the value of a single file.
    + * Returns a kmalloced value: call free() on it after use.
    + * len indicates length in bytes.
    + */
    +void *xenbus_read(struct xenbus_transaction t,
    + const char *dir, const char *node, unsigned int *len)
    +{
    + char *path;
    + void *ret;
    +
    + path = join(dir, node);
    + if (IS_ERR(path))
    + return (void *)path;
    +
    + ret = xs_single(t, XS_READ, path, len);
    + kfree(path);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_read);
    +
    +/* Write the value of a single file.
    + * Returns -err on failure.
    + */
    +int xenbus_write(struct xenbus_transaction t,
    + const char *dir, const char *node, const char *string)
    +{
    + const char *path;
    + struct kvec iovec[2];
    + int ret;
    +
    + path = join(dir, node);
    + if (IS_ERR(path))
    + return PTR_ERR(path);
    +
    + iovec[0].iov_base = (void *)path;
    + iovec[0].iov_len = strlen(path) + 1;
    + iovec[1].iov_base = (void *)string;
    + iovec[1].iov_len = strlen(string);
    +
    + ret = xs_error(xs_talkv(t, XS_WRITE, iovec, ARRAY_SIZE(iovec), NULL));
    + kfree(path);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_write);
    +
    +/* Create a new directory. */
    +int xenbus_mkdir(struct xenbus_transaction t,
    + const char *dir, const char *node)
    +{
    + char *path;
    + int ret;
    +
    + path = join(dir, node);
    + if (IS_ERR(path))
    + return PTR_ERR(path);
    +
    + ret = xs_error(xs_single(t, XS_MKDIR, path, NULL));
    + kfree(path);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_mkdir);
    +
    +/* Destroy a file or directory (directories must be empty). */
    +int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node)
    +{
    + char *path;
    + int ret;
    +
    + path = join(dir, node);
    + if (IS_ERR(path))
    + return PTR_ERR(path);
    +
    + ret = xs_error(xs_single(t, XS_RM, path, NULL));
    + kfree(path);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_rm);
    +
    +/* Start a transaction: changes by others will not be seen during this
    + * transaction, and changes will not be visible to others until end.
    + */
    +int xenbus_transaction_start(struct xenbus_transaction *t)
    +{
    + char *id_str;
    +
    + down_read(&xs_state.transaction_mutex);
    +
    + id_str = xs_single(XBT_NIL, XS_TRANSACTION_START, "", NULL);
    + if (IS_ERR(id_str)) {
    + up_read(&xs_state.transaction_mutex);
    + return PTR_ERR(id_str);
    + }
    +
    + t->id = simple_strtoul(id_str, NULL, 0);
    + kfree(id_str);
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_transaction_start);
    +
    +/* End a transaction.
    + * If abandon is true, transaction is discarded instead of committed.
    + */
    +int xenbus_transaction_end(struct xenbus_transaction t, int abort)
    +{
    + char abortstr[2];
    + int err;
    +
    + if (abort)
    + strcpy(abortstr, "F");
    + else
    + strcpy(abortstr, "T");
    +
    + err = xs_error(xs_single(t, XS_TRANSACTION_END, abortstr, NULL));
    +
    + up_read(&xs_state.transaction_mutex);
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_transaction_end);
    +
    +/* Single read and scanf: returns -errno or num scanned. */
    +int xenbus_scanf(struct xenbus_transaction t,
    + const char *dir, const char *node, const char *fmt, ...)
    +{
    + va_list ap;
    + int ret;
    + char *val;
    +
    + val = xenbus_read(t, dir, node, NULL);
    + if (IS_ERR(val))
    + return PTR_ERR(val);
    +
    + va_start(ap, fmt);
    + ret = vsscanf(val, fmt, ap);
    + va_end(ap);
    + kfree(val);
    + /* Distinctive errno. */
    + if (ret == 0)
    + return -ERANGE;
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_scanf);
    +
    +/* Single printf and write: returns -errno or 0. */
    +int xenbus_printf(struct xenbus_transaction t,
    + const char *dir, const char *node, const char *fmt, ...)
    +{
    + va_list ap;
    + int ret;
    +#define PRINTF_BUFFER_SIZE 4096
    + char *printf_buffer;
    +
    + printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
    + if (printf_buffer == NULL)
    + return -ENOMEM;
    +
    + va_start(ap, fmt);
    + ret = vsnprintf(printf_buffer, PRINTF_BUFFER_SIZE, fmt, ap);
    + va_end(ap);
    +
    + BUG_ON(ret > PRINTF_BUFFER_SIZE-1);
    + ret = xenbus_write(t, dir, node, printf_buffer);
    +
    + kfree(printf_buffer);
    +
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_printf);
    +
    +/* Takes tuples of names, scanf-style args, and void **, NULL terminated. */
    +int xenbus_gather(struct xenbus_transaction t, const char *dir, ...)
    +{
    + va_list ap;
    + const char *name;
    + int ret = 0;
    +
    + va_start(ap, dir);
    + while (ret == 0 && (name = va_arg(ap, char *)) != NULL) {
    + const char *fmt = va_arg(ap, char *);
    + void *result = va_arg(ap, void *);
    + char *p;
    +
    + p = xenbus_read(t, dir, name, NULL);
    + if (IS_ERR(p)) {
    + ret = PTR_ERR(p);
    + break;
    + }
    + if (fmt) {
    + if (sscanf(p, fmt, result) == 0)
    + ret = -EINVAL;
    + kfree(p);
    + } else
    + *(char **)result = p;
    + }
    + va_end(ap);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(xenbus_gather);
    +
    +static int xs_watch(const char *path, const char *token)
    +{
    + struct kvec iov[2];
    +
    + iov[0].iov_base = (void *)path;
    + iov[0].iov_len = strlen(path) + 1;
    + iov[1].iov_base = (void *)token;
    + iov[1].iov_len = strlen(token) + 1;
    +
    + return xs_error(xs_talkv(XBT_NIL, XS_WATCH, iov,
    + ARRAY_SIZE(iov), NULL));
    +}
    +
    +static int xs_unwatch(const char *path, const char *token)
    +{
    + struct kvec iov[2];
    +
    + iov[0].iov_base = (char *)path;
    + iov[0].iov_len = strlen(path) + 1;
    + iov[1].iov_base = (char *)token;
    + iov[1].iov_len = strlen(token) + 1;
    +
    + return xs_error(xs_talkv(XBT_NIL, XS_UNWATCH, iov,
    + ARRAY_SIZE(iov), NULL));
    +}
    +
    +static struct xenbus_watch *find_watch(const char *token)
    +{
    + struct xenbus_watch *i, *cmp;
    +
    + cmp = (void *)simple_strtoul(token, NULL, 16);
    +
    + list_for_each_entry(i, &watches, list)
    + if (i == cmp)
    + return i;
    +
    + return NULL;
    +}
    +
    +/* Register callback to watch this node. */
    +int register_xenbus_watch(struct xenbus_watch *watch)
    +{
    + /* Pointer in ascii is the token. */
    + char token[sizeof(watch) * 2 + 1];
    + int err;
    +
    + sprintf(token, "%lX", (long)watch);
    +
    + down_read(&xs_state.watch_mutex);
    +
    + spin_lock(&watches_lock);
    + BUG_ON(find_watch(token));
    + list_add(&watch->list, &watches);
    + spin_unlock(&watches_lock);
    +
    + err = xs_watch(watch->node, token);
    +
    + /* Ignore errors due to multiple registration. */
    + if ((err != 0) && (err != -EEXIST)) {
    + spin_lock(&watches_lock);
    + list_del(&watch->list);
    + spin_unlock(&watches_lock);
    + }
    +
    + up_read(&xs_state.watch_mutex);
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(register_xenbus_watch);
    +
    +void unregister_xenbus_watch(struct xenbus_watch *watch)
    +{
    + struct xs_stored_msg *msg, *tmp;
    + char token[sizeof(watch) * 2 + 1];
    + int err;
    +
    + sprintf(token, "%lX", (long)watch);
    +
    + down_read(&xs_state.watch_mutex);
    +
    + spin_lock(&watches_lock);
    + BUG_ON(!find_watch(token));
    + list_del(&watch->list);
    + spin_unlock(&watches_lock);
    +
    + err = xs_unwatch(watch->node, token);
    + if (err)
    + printk(KERN_WARNING
    + "XENBUS Failed to release watch %s: %i\n",
    + watch->node, err);
    +
    + up_read(&xs_state.watch_mutex);
    +
    + /* Make sure there are no callbacks running currently (unless
    + its us) */
    + if (current->pid != xenwatch_pid)
    + mutex_lock(&xenwatch_mutex);
    +
    + /* Cancel pending watch events. */
    + spin_lock(&watch_events_lock);
    + list_for_each_entry_safe(msg, tmp, &watch_events, list) {
    + if (msg->u.watch.handle != watch)
    + continue;
    + list_del(&msg->list);
    + kfree(msg->u.watch.vec);
    + kfree(msg);
    + }
    + spin_unlock(&watch_events_lock);
    +
    + if (current->pid != xenwatch_pid)
    + mutex_unlock(&xenwatch_mutex);
    +}
    +EXPORT_SYMBOL_GPL(unregister_xenbus_watch);
    +
    +void xs_suspend(void)
    +{
    + down_write(&xs_state.transaction_mutex);
    + down_write(&xs_state.watch_mutex);
    + mutex_lock(&xs_state.request_mutex);
    + mutex_lock(&xs_state.response_mutex);
    +}
    +
    +void xs_resume(void)
    +{
    + struct xenbus_watch *watch;
    + char token[sizeof(watch) * 2 + 1];
    +
    + mutex_unlock(&xs_state.response_mutex);
    + mutex_unlock(&xs_state.request_mutex);
    + up_write(&xs_state.transaction_mutex);
    +
    + /* No need for watches_lock: the watch_mutex is sufficient. */
    + list_for_each_entry(watch, &watches, list) {
    + sprintf(token, "%lX", (long)watch);
    + xs_watch(watch->node, token);
    + }
    +
    + up_write(&xs_state.watch_mutex);
    +}
    +
    +void xs_suspend_cancel(void)
    +{
    + mutex_unlock(&xs_state.response_mutex);
    + mutex_unlock(&xs_state.request_mutex);
    + up_write(&xs_state.watch_mutex);
    + up_write(&xs_state.transaction_mutex);
    +}
    +
    +static int xenwatch_thread(void *unused)
    +{
    + struct list_head *ent;
    + struct xs_stored_msg *msg;
    +
    + for (;;) {
    + wait_event_interruptible(watch_events_waitq,
    + !list_empty(&watch_events));
    +
    + if (kthread_should_stop())
    + break;
    +
    + mutex_lock(&xenwatch_mutex);
    +
    + spin_lock(&watch_events_lock);
    + ent = watch_events.next;
    + if (ent != &watch_events)
    + list_del(ent);
    + spin_unlock(&watch_events_lock);
    +
    + if (ent != &watch_events) {
    + msg = list_entry(ent, struct xs_stored_msg, list);
    + msg->u.watch.handle->callback(
    + msg->u.watch.handle,
    + (const char **)msg->u.watch.vec,
    + msg->u.watch.vec_size);
    + kfree(msg->u.watch.vec);
    + kfree(msg);
    + }
    +
    + mutex_unlock(&xenwatch_mutex);
    + }
    +
    + return 0;
    +}
    +
    +static int process_msg(void)
    +{
    + struct xs_stored_msg *msg;
    + char *body;
    + int err;
    +
    + /*
    + * We must disallow save/restore while reading a xenstore message.
    + * A partial read across s/r leaves us out of sync with xenstored.
    + */
    + for (;;) {
    + err = xb_wait_for_data_to_read();
    + if (err)
    + return err;
    + mutex_lock(&xs_state.response_mutex);
    + if (xb_data_to_read())
    + break;
    + /* We raced with save/restore: pending data 'disappeared'. */
    + mutex_unlock(&xs_state.response_mutex);
    + }
    +
    +
    + msg = kmalloc(sizeof(*msg), GFP_KERNEL);
    + if (msg == NULL) {
    + err = -ENOMEM;
    + goto out;
    + }
    +
    + err = xb_read(&msg->hdr, sizeof(msg->hdr));
    + if (err) {
    + kfree(msg);
    + goto out;
    + }
    +
    + body = kmalloc(msg->hdr.len + 1, GFP_KERNEL);
    + if (body == NULL) {
    + kfree(msg);
    + err = -ENOMEM;
    + goto out;
    + }
    +
    + err = xb_read(body, msg->hdr.len);
    + if (err) {
    + kfree(body);
    + kfree(msg);
    + goto out;
    + }
    + body[msg->hdr.len] = '\0';
    +
    + if (msg->hdr.type == XS_WATCH_EVENT) {
    + msg->u.watch.vec = split(body, msg->hdr.len,
    + &msg->u.watch.vec_size);
    + if (IS_ERR(msg->u.watch.vec)) {
    + kfree(msg);
    + err = PTR_ERR(msg->u.watch.vec);
    + goto out;
    + }
    +
    + spin_lock(&watches_lock);
    + msg->u.watch.handle = find_watch(
    + msg->u.watch.vec[XS_WATCH_TOKEN]);
    + if (msg->u.watch.handle != NULL) {
    + spin_lock(&watch_events_lock);
    + list_add_tail(&msg->list, &watch_events);
    + wake_up(&watch_events_waitq);
    + spin_unlock(&watch_events_lock);
    + } else {
    + kfree(msg->u.watch.vec);
    + kfree(msg);
    + }
    + spin_unlock(&watches_lock);
    + } else {
    + msg->u.reply.body = body;
    + spin_lock(&xs_state.reply_lock);
    + list_add_tail(&msg->list, &xs_state.reply_list);
    + spin_unlock(&xs_state.reply_lock);
    + wake_up(&xs_state.reply_waitq);
    + }
    +
    + out:
    + mutex_unlock(&xs_state.response_mutex);
    + return err;
    +}
    +
    +static int xenbus_thread(void *unused)
    +{
    + int err;
    +
    + for (;;) {
    + err = process_msg();
    + if (err)
    + printk(KERN_WARNING "XENBUS error %d while reading "
    + "message\n", err);
    + if (kthread_should_stop())
    + break;
    + }
    +
    + return 0;
    +}
    +
    +int xs_init(void)
    +{
    + int err;
    + struct task_struct *task;
    +
    + INIT_LIST_HEAD(&xs_state.reply_list);
    + spin_lock_init(&xs_state.reply_lock);
    + init_waitqueue_head(&xs_state.reply_waitq);
    +
    + mutex_init(&xs_state.request_mutex);
    + mutex_init(&xs_state.response_mutex);
    + init_rwsem(&xs_state.transaction_mutex);
    + init_rwsem(&xs_state.watch_mutex);
    +
    + /* Initialize the shared memory rings to talk to xenstored */
    + err = xb_init_comms();
    + if (err)
    + return err;
    +
    + task = kthread_run(xenwatch_thread, NULL, "xenwatch");
    + if (IS_ERR(task))
    + return PTR_ERR(task);
    + xenwatch_pid = task->pid;
    +
    + task = kthread_run(xenbus_thread, NULL, "xenbus");
    + if (IS_ERR(task))
    + return PTR_ERR(task);
    +
    + return 0;
    +}
    ===================================================================
    --- a/include/asm-i386/xen/hypervisor.h
    +++ b/include/asm-i386/xen/hypervisor.h
    @@ -42,6 +42,7 @@

    #include <asm/ptrace.h>
    #include <asm/page.h>
    +#include <asm/desc.h>
    #if defined(__i386__)
    # ifdef CONFIG_X86_PAE
    # include <asm-generic/pgtable-nopud.h>
    ===================================================================
    --- /dev/null
    +++ b/include/xen/xenbus.h
    @@ -0,0 +1,232 @@
    +/******************************************************************************
    + * xenbus.h
    + *
    + * Talks to Xen Store to figure out what devices we have.
    + *
    + * Copyright (C) 2005 Rusty Russell, IBM Corporation
    + * Copyright (C) 2005 XenSource Ltd.
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License version 2
    + * as published by the Free Software Foundation; or, when distributed
    + * separately from the Linux kernel or incorporated into other
    + * software packages, subject to the following license:
    + *
    + * Permission is hereby granted, free of charge, to any person obtaining a copy
    + * of this source file (the "Software"), to deal in the Software without
    + * restriction, including without limitation the rights to use, copy, modify,
    + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
    + * and to permit persons to whom the Software is furnished to do so, subject to
    + * the following conditions:
    + *
    + * The above copyright notice and this permission notice shall be included in
    + * all copies or substantial portions of the Software.
    + *
    + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    + * IN THE SOFTWARE.
    + */
    +
    +#ifndef _XEN_XENBUS_H
    +#define _XEN_XENBUS_H
    +
    +#include <linux/device.h>
    +#include <linux/notifier.h>
    +#include <linux/mutex.h>
    +#include <linux/completion.h>
    +#include <linux/init.h>
    +#include <xen/interface/xen.h>
    +#include <xen/interface/grant_table.h>
    +#include <xen/interface/io/xenbus.h>
    +#include <xen/interface/io/xs_wire.h>
    +
    +/* Register callback to watch this node. */
    +struct xenbus_watch
    +{
    + struct list_head list;
    +
    + /* Path being watched. */
    + const char *node;
    +
    + /* Callback (executed in a process context with no locks held). */
    + void (*callback)(struct xenbus_watch *,
    + const char **vec, unsigned int len);
    +};
    +
    +
    +/* A xenbus device. */
    +struct xenbus_device {
    + const char *devicetype;
    + const char *nodename;
    + const char *otherend;
    + int otherend_id;
    + struct xenbus_watch otherend_watch;
    + struct device dev;
    + enum xenbus_state state;
    + struct completion down;
    +};
    +
    +static inline struct xenbus_device *to_xenbus_device(struct device *dev)
    +{
    + return container_of(dev, struct xenbus_device, dev);
    +}
    +
    +struct xenbus_device_id
    +{
    + /* .../device/<device_type>/<identifier> */
    + char devicetype[32]; /* General class of device. */
    +};
    +
    +/* A xenbus driver. */
    +struct xenbus_driver {
    + char *name;
    + struct module *owner;
    + const struct xenbus_device_id *ids;
    + int (*probe)(struct xenbus_device *dev,
    + const struct xenbus_device_id *id);
    + void (*otherend_changed)(struct xenbus_device *dev,
    + enum xenbus_state backend_state);
    + int (*remove)(struct xenbus_device *dev);
    + int (*suspend)(struct xenbus_device *dev);
    + int (*suspend_cancel)(struct xenbus_device *dev);
    + int (*resume)(struct xenbus_device *dev);
    + int (*uevent)(struct xenbus_device *, char **, int, char *, int);
    + struct device_driver driver;
    + int (*read_otherend_details)(struct xenbus_device *dev);
    +};
    +
    +static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
    +{
    + return container_of(drv, struct xenbus_driver, driver);
    +}
    +
    +int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
    + struct module *owner,
    + const char *mod_name);
    +
    +static inline int __must_check
    +xenbus_register_frontend(struct xenbus_driver *drv)
    +{
    + WARN_ON(drv->owner != THIS_MODULE);
    + return __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME);
    +}
    +
    +int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
    + struct module *owner,
    + const char *mod_name);
    +static inline int __must_check
    +xenbus_register_backend(struct xenbus_driver *drv)
    +{
    + WARN_ON(drv->owner != THIS_MODULE);
    + return __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME);
    +}
    +
    +void xenbus_unregister_driver(struct xenbus_driver *drv);
    +
    +struct xenbus_transaction
    +{
    + u32 id;
    +};
    +
    +/* Nil transaction ID. */
    +#define XBT_NIL ((struct xenbus_transaction) { 0 })
    +
    +int __init xenbus_dev_init(void);
    +
    +char **xenbus_directory(struct xenbus_transaction t,
    + const char *dir, const char *node, unsigned int *num);
    +void *xenbus_read(struct xenbus_transaction t,
    + const char *dir, const char *node, unsigned int *len);
    +int xenbus_write(struct xenbus_transaction t,
    + const char *dir, const char *node, const char *string);
    +int xenbus_mkdir(struct xenbus_transaction t,
    + const char *dir, const char *node);
    +int xenbus_exists(struct xenbus_transaction t,
    + const char *dir, const char *node);
    +int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
    +int xenbus_transaction_start(struct xenbus_transaction *t);
    +int xenbus_transaction_end(struct xenbus_transaction t, int abort);
    +
    +/* Single read and scanf: returns -errno or num scanned if > 0. */
    +int xenbus_scanf(struct xenbus_transaction t,
    + const char *dir, const char *node, const char *fmt, ...)
    + __attribute__((format(scanf, 4, 5)));
    +
    +/* Single printf and write: returns -errno or 0. */
    +int xenbus_printf(struct xenbus_transaction t,
    + const char *dir, const char *node, const char *fmt, ...)
    + __attribute__((format(printf, 4, 5)));
    +
    +/* Generic read function: NULL-terminated triples of name,
    + * sprintf-style type string, and pointer. Returns 0 or errno.*/
    +int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
    +
    +/* notifer routines for when the xenstore comes up */
    +extern int xenstored_ready;
    +int register_xenstore_notifier(struct notifier_block *nb);
    +void unregister_xenstore_notifier(struct notifier_block *nb);
    +
    +int register_xenbus_watch(struct xenbus_watch *watch);
    +void unregister_xenbus_watch(struct xenbus_watch *watch);
    +void xs_suspend(void);
    +void xs_resume(void);
    +void xs_suspend_cancel(void);
    +
    +/* Used by xenbus_dev to borrow kernel's store connection. */
    +void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
    +
    +/* Prepare for domain suspend: then resume or cancel the suspend. */
    +void xenbus_suspend(void);
    +void xenbus_resume(void);
    +void xenbus_probe(struct work_struct *);
    +void xenbus_suspend_cancel(void);
    +
    +#define XENBUS_IS_ERR_READ(str) ({ \
    + if (!IS_ERR(str) && strlen(str) == 0) { \
    + kfree(str); \
    + str = ERR_PTR(-ERANGE); \
    + } \
    + IS_ERR(str); \
    +})
    +
    +#define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
    +
    +int xenbus_watch_path(struct xenbus_device *dev, const char *path,
    + struct xenbus_watch *watch,
    + void (*callback)(struct xenbus_watch *,
    + const char **, unsigned int));
    +int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
    + void (*callback)(struct xenbus_watch *,
    + const char **, unsigned int),
    + const char *pathfmt, ...)
    + __attribute__ ((format (printf, 4, 5)));
    +
    +int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
    +int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
    +int xenbus_map_ring_valloc(struct xenbus_device *dev,
    + int gnt_ref, void **vaddr);
    +int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
    + grant_handle_t *handle, void *vaddr);
    +
    +int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
    +int xenbus_unmap_ring(struct xenbus_device *dev,
    + grant_handle_t handle, void *vaddr);
    +
    +int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
    +int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);
    +int xenbus_free_evtchn(struct xenbus_device *dev, int port);
    +
    +enum xenbus_state xenbus_read_driver_state(const char *path);
    +
    +void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
    +void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
    +
    +const char *xenbus_strstate(enum xenbus_state state);
    +int xenbus_dev_is_online(struct xenbus_device *dev);
    +int xenbus_frontend_closed(struct xenbus_device *dev);
    +
    +#endif /* _XEN_XENBUS_H */
    --

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