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xen: separate out frontend xenbus 

Impact: refactor

Make a distinct frontend xenbus, in preparation for adding a backend xenbus.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[corresponds to 2fd433a4188f in git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
 with adjustments to reflect changes in the code which is moved]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Ian Campbell 2009-02-09 12:05:51 -08:00 committed by Konrad Rzeszutek Wilk
parent cf7d7e5a19
commit 2de06cc1f1
6 changed files with 367 additions and 305 deletions
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1
drivers/block/Kconfig
View File

@ -464,6 +464,7 @@ config XEN_BLKDEV_FRONTEND
tristate "Xen virtual block device support"
depends on XEN
default y
select XEN_XENBUS_FRONTEND
help
This driver implements the front-end of the Xen virtual
block device driver. It communicates with a back-end driver

3
drivers/xen/Kconfig
View File

@ -62,6 +62,9 @@ config XEN_SYS_HYPERVISOR
virtual environment, /sys/hypervisor will still be present,
but will have no xen contents.
config XEN_XENBUS_FRONTEND
tristate
config XEN_PLATFORM_PCI
tristate "xen platform pci device driver"
depends on XEN_PVHVM

2
drivers/xen/xenbus/Makefile
View File

@ -5,3 +5,5 @@ xenbus-objs += xenbus_client.o
xenbus-objs += xenbus_comms.o
xenbus-objs += xenbus_xs.o
xenbus-objs += xenbus_probe.o
obj-$(CONFIG_XEN_XENBUS_FRONTEND) += xenbus_probe_frontend.o

361
drivers/xen/xenbus/xenbus_probe.c
View File

@ -56,7 +56,6 @@
#include <xen/events.h>
#include <xen/page.h>
#include <xen/platform_pci.h>
#include <xen/hvm.h>
#include "xenbus_comms.h"
@ -73,15 +72,6 @@ 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);
static int xenbus_dev_suspend(struct device *dev, pm_message_t state);
static int xenbus_dev_resume(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)
@ -102,8 +92,10 @@ int xenbus_match(struct device *_dev, struct device_driver *_drv)
return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
}
EXPORT_SYMBOL_GPL(xenbus_match);
static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
{
struct xenbus_device *dev = to_xenbus_device(_dev);
@ -112,25 +104,7 @@ static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
return 0;
}
/* device/<type>/<id> => <type>-<id> */
static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
{
nodename = strchr(nodename, '/');
if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
return -EINVAL;
}
strlcpy(bus_id, nodename + 1, XEN_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;
}
EXPORT_SYMBOL_GPL(xenbus_uevent);
static void free_otherend_details(struct xenbus_device *dev)
{
@ -149,7 +123,28 @@ static void free_otherend_watch(struct xenbus_device *dev)
}
int read_otherend_details(struct xenbus_device *xendev,
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)
{
struct xen_bus_type *bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
return xenbus_watch_pathfmt(dev, &dev->otherend_watch, bus->otherend_changed,
"%s/%s", dev->otherend, "state");
}
int xenbus_read_otherend_details(struct xenbus_device *xendev,
char *id_node, char *path_node)
{
int err = xenbus_gather(XBT_NIL, xendev->nodename,
@ -174,39 +169,11 @@ int read_otherend_details(struct xenbus_device *xendev,
return 0;
}
EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
static int read_backend_details(struct xenbus_device *xendev)
{
return read_otherend_details(xendev, "backend-id", "backend");
}
static struct device_attribute xenbus_dev_attrs[] = {
__ATTR_NULL
};
/* 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,
.dev_attrs = xenbus_dev_attrs,
.suspend = xenbus_dev_suspend,
.resume = xenbus_dev_resume,
},
};
static void otherend_changed(struct xenbus_watch *watch,
const char **vec, unsigned int len)
void xenbus_otherend_changed(struct xenbus_watch *watch,
const char **vec, unsigned int len,
int ignore_on_shutdown)
{
struct xenbus_device *dev =
container_of(watch, struct xenbus_device, otherend_watch);
@ -234,11 +201,7 @@ static void otherend_changed(struct xenbus_watch *watch,
* 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))
if (ignore_on_shutdown && (state == XenbusStateClosing))
xenbus_frontend_closed(dev);
return;
}
@ -246,25 +209,7 @@ static void otherend_changed(struct xenbus_watch *watch,
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");
}
EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
int xenbus_dev_probe(struct device *_dev)
{
@ -310,6 +255,7 @@ int xenbus_dev_probe(struct device *_dev)
xenbus_switch_state(dev, XenbusStateClosed);
return -ENODEV;
}
EXPORT_SYMBOL_GPL(xenbus_dev_probe);
int xenbus_dev_remove(struct device *_dev)
{
@ -327,8 +273,9 @@ int xenbus_dev_remove(struct device *_dev)
xenbus_switch_state(dev, XenbusStateClosed);
return 0;
}
EXPORT_SYMBOL_GPL(xenbus_dev_remove);
static void xenbus_dev_shutdown(struct device *_dev)
void xenbus_dev_shutdown(struct device *_dev)
{
struct xenbus_device *dev = to_xenbus_device(_dev);
unsigned long timeout = 5*HZ;
@ -349,6 +296,7 @@ static void xenbus_dev_shutdown(struct device *_dev)
out:
put_device(&dev->dev);
}
EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
int xenbus_register_driver_common(struct xenbus_driver *drv,
struct xen_bus_type *bus,
@ -362,25 +310,7 @@ int xenbus_register_driver_common(struct xenbus_driver *drv,
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);
EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
void xenbus_unregister_driver(struct xenbus_driver *drv)
{
@ -551,24 +481,7 @@ int xenbus_probe_node(struct xen_bus_type *bus,
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;
}
EXPORT_SYMBOL_GPL(xenbus_probe_node);
static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
{
@ -577,15 +490,23 @@ static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
unsigned int dir_n = 0;
int i;
printk(KERN_CRIT "%s type %s\n", __func__, type);
dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
if (IS_ERR(dir))
if (IS_ERR(dir)) {
printk(KERN_CRIT "%s failed xenbus_directory\n", __func__);
return PTR_ERR(dir);
}
for (i = 0; i < dir_n; i++) {
err = bus->probe(type, dir[i]);
if (err)
printk(KERN_CRIT "%s %d/%d %s\n", __func__, i+1,dir_n, dir[i]);
err = bus->probe(bus, type, dir[i]);
if (err) {
printk(KERN_CRIT "%s failed\n", __func__);
break;
}
}
printk("%s done\n", __func__);
kfree(dir);
return err;
}
@ -596,18 +517,27 @@ int xenbus_probe_devices(struct xen_bus_type *bus)
char **dir;
unsigned int i, dir_n;
printk(KERN_CRIT "%s %s\n", __func__, bus->root);
dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
if (IS_ERR(dir))
if (IS_ERR(dir)) {
printk(KERN_CRIT "%s failed xenbus_directory\n", __func__);
return PTR_ERR(dir);
}
for (i = 0; i < dir_n; i++) {
printk(KERN_CRIT "%s %d/%d %s\n", __func__, i+1,dir_n, dir[i]);
err = xenbus_probe_device_type(bus, dir[i]);
if (err)
if (err) {
printk(KERN_CRIT "%s failed\n", __func__);
break;
}
}
printk("%s done\n", __func__);
kfree(dir);
return err;
}
EXPORT_SYMBOL_GPL(xenbus_probe_devices);
static unsigned int char_count(const char *str, char c)
{
@ -670,32 +600,17 @@ void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
}
EXPORT_SYMBOL_GPL(xenbus_dev_changed);
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 xenbus_dev_suspend(struct device *dev, pm_message_t state)
int xenbus_dev_suspend(struct device *dev, pm_message_t state)
{
int err = 0;
struct xenbus_driver *drv;
struct xenbus_device *xdev;
struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev);
DPRINTK("");
DPRINTK("%s", xdev->nodename);
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, state);
if (err)
@ -703,21 +618,19 @@ static int xenbus_dev_suspend(struct device *dev, pm_message_t state)
"xenbus: suspend %s failed: %i\n", dev_name(dev), err);
return 0;
}
EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
static int xenbus_dev_resume(struct device *dev)
int xenbus_dev_resume(struct device *dev)
{
int err;
struct xenbus_driver *drv;
struct xenbus_device *xdev;
struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev);
DPRINTK("");
DPRINTK("%s", xdev->nodename);
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
@ -748,6 +661,7 @@ static int xenbus_dev_resume(struct device *dev)
return 0;
}
EXPORT_SYMBOL_GPL(xenbus_dev_resume);
/* A flag to determine if xenstored is 'ready' (i.e. has started) */
int xenstored_ready = 0;
@ -776,11 +690,6 @@ void xenbus_probe(struct work_struct *unused)
{
xenstored_ready = 1;
/* 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);
}
@ -811,15 +720,6 @@ static int __init xenbus_init(void)
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.
*/
@ -874,7 +774,7 @@ static int __init xenbus_init(void)
if (err) {
printk(KERN_WARNING
"XENBUS: Error initializing xenstore comms: %i\n", err);
goto out_unreg_back;
goto out_error;
}
#ifdef CONFIG_XEN_COMPAT_XENFS
@ -885,135 +785,16 @@ static int __init xenbus_init(void)
proc_mkdir("xen", NULL);
#endif
printk(KERN_CRIT "%s ok\n", __func__);
return 0;
out_unreg_back:
xenbus_backend_bus_unregister();
out_unreg_front:
bus_unregister(&xenbus_frontend.bus);
out_error:
if (page != 0)
free_page(page);
return err;
}
postcore_initcall(xenbus_init);
MODULE_LICENSE("GPL");
static int is_device_connecting(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 ||
(xendev->state == XenbusStateConnected &&
xendrv->is_ready && !xendrv->is_ready(xendev)));
}
static int exists_connecting_device(struct device_driver *drv)
{
return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
is_device_connecting);
}
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) {
enum xenbus_state rstate = XenbusStateUnknown;
if (xendev->otherend)
rstate = xenbus_read_driver_state(xendev->otherend);
printk(KERN_WARNING "XENBUS: Timeout connecting "
"to device: %s (local state %d, remote state %d)\n",
xendev->nodename, xendev->state, rstate);
}
return 0;
}
/* We only wait for device setup after most initcalls have run. */
static int ready_to_wait_for_devices;
/*
* On a 5-minute 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 start = jiffies;
struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
unsigned int seconds_waited = 0;
if (!ready_to_wait_for_devices || !xen_domain())
return;
while (exists_connecting_device(drv)) {
if (time_after(jiffies, start + (seconds_waited+5)*HZ)) {
if (!seconds_waited)
printk(KERN_WARNING "XENBUS: Waiting for "
"devices to initialise: ");
seconds_waited += 5;
printk("%us...", 300 - seconds_waited);
if (seconds_waited == 300)
break;
}
schedule_timeout_interruptible(HZ/10);
}
if (seconds_waited)
printk("\n");
bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
print_device_status);
}
#ifndef MODULE
static int __init boot_wait_for_devices(void)
{
if (xen_hvm_domain() && !xen_platform_pci_unplug)
return -ENODEV;
ready_to_wait_for_devices = 1;
wait_for_devices(NULL);
return 0;
}
late_initcall(boot_wait_for_devices);
#endif

30
drivers/xen/xenbus/xenbus_probe.h
View File

@ -36,26 +36,13 @@
#define XEN_BUS_ID_SIZE 20
#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[XEN_BUS_ID_SIZE], const char *nodename);
int (*probe)(const char *type, const char *dir);
int (*probe)(struct xen_bus_type *bus, const char *type, const char *dir);
void (*otherend_changed)(struct xenbus_watch *watch, const char **vec, unsigned int len);
struct bus_type bus;
};
@ -73,4 +60,17 @@ extern int xenbus_probe_devices(struct xen_bus_type *bus);
extern void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);
extern int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env);
extern void xenbus_dev_shutdown(struct device *_dev);
extern int xenbus_dev_suspend(struct device *dev, pm_message_t state);
extern int xenbus_dev_resume(struct device *dev);
extern void xenbus_otherend_changed(struct xenbus_watch *watch,
const char **vec, unsigned int len,
int ignore_on_shutdown);
extern int xenbus_read_otherend_details(struct xenbus_device *xendev,
char *id_node, char *path_node);
#endif

275
drivers/xen/xenbus/xenbus_probe_frontend.c Normal file
View File

@ -0,0 +1,275 @@
#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/proc_fs.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 <xen/platform_pci.h>
#include "xenbus_comms.h"
#include "xenbus_probe.h"
/* device/<type>/<id> => <type>-<id> */
static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
{
nodename = strchr(nodename, '/');
if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
return -EINVAL;
}
strlcpy(bus_id, nodename + 1, XEN_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;
}
/* device/<typename>/<name> */
static int xenbus_probe_frontend(struct xen_bus_type *bus, const char *type, const char *name)
{
char *nodename;
int err;
nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, name);
if (!nodename)
return -ENOMEM;
DPRINTK("%s", nodename);
err = xenbus_probe_node(bus, type, nodename);
kfree(nodename);
return err;
}
static void backend_changed(struct xenbus_watch *watch,
const char **vec, unsigned int len)
{
xenbus_otherend_changed(watch, vec, len, 1);
}
static struct device_attribute xenbus_frontend_dev_attrs[] = {
__ATTR_NULL
};
static struct xen_bus_type xenbus_frontend = {
.root = "device",
.levels = 2, /* device/type/<id> */
.get_bus_id = frontend_bus_id,
.probe = xenbus_probe_frontend,
.otherend_changed = backend_changed,
.bus = {
.name = "xen",
.match = xenbus_match,
.uevent = xenbus_uevent,
.probe = xenbus_dev_probe,
.remove = xenbus_dev_remove,
.shutdown = xenbus_dev_shutdown,
.dev_attrs= xenbus_frontend_dev_attrs,
.suspend = xenbus_dev_suspend,
.resume = xenbus_dev_resume,
},
};
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 read_backend_details(struct xenbus_device *xendev)
{
return xenbus_read_otherend_details(xendev, "backend-id", "backend");
}
static int is_device_connecting(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 ||
(xendev->state == XenbusStateConnected &&
xendrv->is_ready && !xendrv->is_ready(xendev)));
}
static int exists_connecting_device(struct device_driver *drv)
{
return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
is_device_connecting);
}
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) {
enum xenbus_state rstate = XenbusStateUnknown;
if (xendev->otherend)
rstate = xenbus_read_driver_state(xendev->otherend);
printk(KERN_WARNING "XENBUS: Timeout connecting "
"to device: %s (local state %d, remote state %d)\n",
xendev->nodename, xendev->state, rstate);
}
return 0;
}
/* We only wait for device setup after most initcalls have run. */
static int ready_to_wait_for_devices;
/*
* On a 5-minute 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 start = jiffies;
struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
unsigned int seconds_waited = 0;
if (!ready_to_wait_for_devices || !xen_domain())
return;
while (exists_connecting_device(drv)) {
if (time_after(jiffies, start + (seconds_waited+5)*HZ)) {
if (!seconds_waited)
printk(KERN_WARNING "XENBUS: Waiting for "
"devices to initialise: ");
seconds_waited += 5;
printk("%us...", 300 - seconds_waited);
if (seconds_waited == 300)
break;
}
schedule_timeout_interruptible(HZ/10);
}
if (seconds_waited)
printk("\n");
bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
print_device_status);
}
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);
static int __init xenbus_probe_frontend_init(void)
{
int err;
DPRINTK("");
/* Register ourselves with the kernel bus subsystem */
err = bus_register(&xenbus_frontend.bus);
if (err) {
printk(KERN_CRIT "%s didn't register bus!\n", __func__);
return err;
}
printk(KERN_CRIT "%s bus registered ok\n", __func__);
if (!xen_initial_domain()) {
/* Enumerate devices in xenstore and watch for changes. */
xenbus_probe_devices(&xenbus_frontend);
printk(KERN_CRIT "%s devices probed ok\n", __func__);
register_xenbus_watch(&fe_watch);
printk(KERN_CRIT "%s watch add ok ok\n", __func__);
printk(KERN_CRIT "%s all done\n", __func__);
}
return 0;
}
module_init(xenbus_probe_frontend_init);
#ifndef MODULE
static int __init boot_wait_for_devices(void)
{
if (xen_hvm_domain() && !xen_platform_pci_unplug)
return -ENODEV;
ready_to_wait_for_devices = 1;
wait_for_devices(NULL);
return 0;
}
late_initcall(boot_wait_for_devices);
#endif