/******************************************************************************
* 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 <linux/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;
}
static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
{
struct xenbus_device *dev = to_xenbus_device(_dev);
if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
return -ENOMEM;
return 0;
}
/* 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,
.uevent = xenbus_uevent,
.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\n",
vec[XS_WATCH_PATH]);
return;
}
state = xenbus_read_driver_state(dev->otherend);
dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
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);
static ssize_t xendev_show_modalias(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
}
DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, 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_nodename;
err = device_create_file(&xendev->dev, &dev_attr_modalias);
if (err)
goto fail_remove_devtype;
return 0;
fail_remove_devtype:
device_remove_file(&xendev->dev, &dev_attr_devtype);
fail_remove_nodename:
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 (!xen_domain())
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 (xen_initial_domain()) {
/* 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 (!xen_initial_domain())
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;
struct xenbus_driver *xendrv;
/*
* 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;
xendrv = to_xenbus_driver(dev->driver);
return (xendev->state != XenbusStateConnected ||
(xendrv->is_ready && !xendrv->is_ready(xendev)));
}
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 || !xen_domain())
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
