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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Update probe code for backend layout.
# HG changeset patch
# User cl349@xxxxxxxxxxxxxxxxxxxx
# Node ID 9471090bb8ec4c01be2531c84510879e235bd4dc
# Parent 18f04796ea89798c85e843912856994bfa2f9d65
Update probe code for backend layout.
Backend directories are of form backend/<type>/<frontend-uuid>/<id>.
This extra level makes an asymmetry with front ends (device/type/id) and
are too long to make nice bus-ids under Linux, but the code isn't too
horrible, and an OS which only wants to be a guest doesn't need to implement
it. It allows backends to calculate the front-end path directly, which
is a nice benefit.
Also: subtype matching is tightened: they must match exactly. That way a future
variant which requires a specific driver will not match current drivers.
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
diff -r 18f04796ea89 -r 9471090bb8ec
linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c Wed Aug 17
12:30:04 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c Thu Aug 18
18:54:38 2005
@@ -48,15 +48,8 @@
match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
{
for (; !streq(arr->devicetype, ""); arr++) {
- if (!streq(arr->devicetype, dev->devicetype))
- continue;
-
- /* If they don't care what subtype, it's a match. */
- if (streq(arr->subtype, ""))
- return arr;
-
- /* If they care, device must have (same) subtype. */
- if (dev->subtype && streq(arr->subtype, dev->subtype))
+ if (streq(arr->devicetype, dev->devicetype) &&
+ streq(arr->subtype, dev->subtype ?: ""))
return arr;
}
return NULL;
@@ -72,10 +65,101 @@
return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
}
+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;
+};
+
+/* 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;
+}
+
/* Bus type for frontend drivers. */
-static struct bus_type xenbus_type = {
- .name = "xenbus",
- .match = xenbus_match,
+static int xenbus_probe_frontend(const char *type, const char *name);
+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 = "xenbus",
+ .match = xenbus_match,
+ },
+};
+
+/* For backends, does lookup on uuid (up to /). Returns domid, or -errno. */
+int xenbus_uuid_to_domid(const char *uuid)
+{
+ int err, domid, len;
+ char path[strlen("/domain/") + 50];
+
+ len = strcspn(uuid, "/");
+ if (snprintf(path, sizeof(path), "/domain/%.*s", len, uuid)
+ >= sizeof(path))
+ return -ENOSPC;
+ err = xenbus_scanf(path, "id", "%i", &domid);
+ if (err != 1)
+ return err;
+ return domid;
+}
+
+/* backend/<type>/<fe-uuid>/<id> => <type>-<fe-domid>-<id> */
+static int backend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename)
+{
+ unsigned int typelen, uuidlen;
+ int domid;
+ const char *p;
+
+ nodename = strchr(nodename, '/');
+ if (!nodename)
+ return -EINVAL;
+ nodename++;
+ typelen = strcspn(nodename, "/");
+ if (!typelen || nodename[typelen] != '/')
+ return -EINVAL;
+ p = nodename + typelen + 1;
+ uuidlen = strcspn(p, "/");
+ if (!uuidlen || p[uuidlen] != '/')
+ return -EINVAL;
+ domid = xenbus_uuid_to_domid(p);
+ if (domid < 0)
+ return domid;
+ p += uuidlen + 1;
+
+ if (snprintf(bus_id, BUS_ID_SIZE,
+ "%.*s-%i-%s", typelen, nodename, domid, p) >= BUS_ID_SIZE)
+ return -ENOSPC;
+ return 0;
+}
+
+static int xenbus_probe_backend(const char *type, const char *uuid);
+static struct xen_bus_type xenbus_backend = {
+ .root = "backend",
+ .levels = 3, /* backend/type/<frontend>/<id> */
+ .get_bus_id = backend_bus_id,
+ .probe = xenbus_probe_backend,
+ .bus = {
+ .name = "xenbus-backend",
+ .match = xenbus_match,
+ },
};
static int xenbus_dev_probe(struct device *_dev)
@@ -104,12 +188,13 @@
return drv->remove(dev);
}
-int xenbus_register_driver(struct xenbus_driver *drv)
+static int xenbus_register_driver(struct xenbus_driver *drv,
+ struct xen_bus_type *bus)
{
int err;
drv->driver.name = drv->name;
- drv->driver.bus = &xenbus_type;
+ drv->driver.bus = &bus->bus;
drv->driver.owner = drv->owner;
drv->driver.probe = xenbus_dev_probe;
drv->driver.remove = xenbus_dev_remove;
@@ -120,6 +205,16 @@
return err;
}
+int xenbus_register_device(struct xenbus_driver *drv)
+{
+ return xenbus_register_driver(drv, &xenbus_frontend);
+}
+
+int xenbus_register_backend(struct xenbus_driver *drv)
+{
+ return xenbus_register_driver(drv, &xenbus_backend);
+}
+
void xenbus_unregister_driver(struct xenbus_driver *drv)
{
down(&xenbus_lock);
@@ -130,30 +225,29 @@
struct xb_find_info
{
struct xenbus_device *dev;
- const char *busid;
+ 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 (streq(dev->bus_id, info->busid)) {
- info->dev = container_of(get_device(dev),
- struct xenbus_device, dev);
+ if (streq(xendev->nodename, info->nodename)) {
+ info->dev = xendev;
return 1;
}
return 0;
}
-/* FIXME: device_find is fixed in 2.6.13-rc2 according to Greg KH --RR */
-struct xenbus_device *xenbus_device_find(const char *busid)
-{
- struct xb_find_info info = { .dev = NULL, .busid = busid };
-
- bus_for_each_dev(&xenbus_type, NULL, &info, cmp_dev);
+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 void xenbus_release_device(struct device *dev)
{
@@ -164,18 +258,37 @@
kfree(xendev);
}
}
-/* devices/<typename>/<name> */
-static int xenbus_probe_device(const char *dirpath, const char *devicetype,
- const char *name)
+
+/* Simplified asprintf. */
+static char *kasprintf(const char *fmt, ...)
+{
+ va_list ap;
+ unsigned int len;
+ char *p, dummy[1];
+
+ va_start(ap, fmt);
+ /* FIXME: vsnprintf has a bug, NULL should work */
+ len = vsnprintf(dummy, 0, fmt, ap);
+ va_end(ap);
+
+ p = kmalloc(len + 1, GFP_KERNEL);
+ if (!p)
+ return NULL;
+ va_start(ap, fmt);
+ vsprintf(p, fmt, ap);
+ va_end(ap);
+ return p;
+}
+
+static int xenbus_probe_node(struct xen_bus_type *bus,
+ const char *type,
+ const char *nodename)
{
int err;
struct xenbus_device *xendev;
unsigned int stringlen;
- /* Nodename: /device/<typename>/<name>/ */
- stringlen = strlen(dirpath) + strlen(devicetype) + strlen(name) + 3;
- /* Typename */
- stringlen += strlen(devicetype) + 1;
+ stringlen = strlen(nodename) + 1 + strlen(type) + 1;
xendev = kmalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
if (!xendev)
return -ENOMEM;
@@ -183,38 +296,108 @@
/* Copy the strings into the extra space. */
xendev->nodename = (char *)(xendev + 1);
- sprintf(xendev->nodename, "%s/%s/%s", dirpath, devicetype, name);
+ strcpy(xendev->nodename, nodename);
xendev->devicetype = xendev->nodename + strlen(xendev->nodename) + 1;
- strcpy(xendev->devicetype, devicetype);
-
- /* FIXME: look for "subtype" field. */
- snprintf(xendev->dev.bus_id, BUS_ID_SIZE, "%s-%s", devicetype, name);
- xendev->dev.bus = &xenbus_type;
+ strcpy(xendev->devicetype, type);
+
+ /* This might not exist, but that's OK. */
+ xendev->subtype = xenbus_read(xendev->nodename, "subtype", NULL);
+ if (IS_ERR(xendev->subtype))
+ xendev->subtype = NULL;
+
+ err = bus->get_bus_id(xendev->dev.bus_id, xendev->nodename);
+ if (err) {
+ printk("XENBUS: Failed to get bus id for %s: error %i\n",
+ xendev->nodename, err);
+ kfree(xendev);
+ return err;
+ }
+
+ xendev->dev.bus = &bus->bus;
xendev->dev.release = xenbus_release_device;
/* Register with generic device framework. */
err = device_register(&xendev->dev);
if (err) {
- printk("XENBUS: Registering device %s: error %i\n",
- xendev->dev.bus_id, err);
+ printk("XENBUS: Registering %s device %s: error %i\n",
+ bus->bus.name, xendev->dev.bus_id, err);
kfree(xendev);
}
return err;
}
-static int xenbus_probe_device_type(const char *dirpath, const char *typename)
+/* device/<typename>/<name> */
+static int xenbus_probe_frontend(const char *type, const char *name)
+{
+ char *nodename;
+ int err;
+
+ nodename = kasprintf("%s/%s/%s", xenbus_frontend.root, type, name);
+ if (!nodename)
+ return -ENOMEM;
+
+ err = xenbus_probe_node(&xenbus_frontend, type, nodename);
+ kfree(nodename);
+ return err;
+}
+
+/* backend/<typename>/<frontend-uuid>/<name> */
+static int xenbus_probe_backend_unit(const char *dir,
+ const char *type,
+ const char *name)
+{
+ char *nodename;
+ int err;
+
+ nodename = kasprintf("%s/%s", dir, name);
+ if (!nodename)
+ return -ENOMEM;
+
+ err = xenbus_probe_node(&xenbus_backend, type, nodename);
+ kfree(nodename);
+ return err;
+}
+
+/* backend/<typename>/<frontend-uuid> */
+static int xenbus_probe_backend(const char *type, const char *uuid)
+{
+ char *nodename;
+ int err = 0;
+ char **dir;
+ unsigned int i, dir_n = 0;
+
+ nodename = kasprintf("%s/%s/%s", xenbus_backend.root, type, uuid);
+ if (!nodename)
+ return -ENOMEM;
+
+ dir = xenbus_directory(nodename, "", &dir_n);
+ if (IS_ERR(dir)) {
+ kfree(nodename);
+ return PTR_ERR(dir);
+ }
+
+ for (i = 0; i < dir_n; i++) {
+ err = xenbus_probe_backend_unit(nodename, type, dir[i]);
+ if (err)
+ break;
+ }
+ 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(dirpath, typename, &dir_n);
+ dir = xenbus_directory(bus->root, type, &dir_n);
if (IS_ERR(dir))
return PTR_ERR(dir);
for (i = 0; i < dir_n; i++) {
- err = xenbus_probe_device(dirpath, typename, dir[i]);
+ err = bus->probe(type, dir[i]);
if (err)
break;
}
@@ -222,18 +405,18 @@
return err;
}
-static int xenbus_probe_devices(const char *path)
+static int xenbus_probe_devices(struct xen_bus_type *bus)
{
int err = 0;
char **dir;
unsigned int i, dir_n;
- dir = xenbus_directory(path, "", &dir_n);
+ dir = xenbus_directory(bus->root, "", &dir_n);
if (IS_ERR(dir))
return PTR_ERR(dir);
for (i = 0; i < dir_n; i++) {
- err = xenbus_probe_device_type(path, dir[i]);
+ err = xenbus_probe_device_type(bus, dir[i]);
if (err)
break;
}
@@ -251,58 +434,96 @@
return ret;
}
-static void dev_changed(struct xenbus_watch *watch, const char *node)
-{
- char busid[BUS_ID_SIZE];
+static void dev_changed(const char *node, struct xen_bus_type *bus)
+{
int exists;
struct xenbus_device *dev;
- char *p;
-
- /* Node is of form device/<type>/<identifier>[/...] */
- if (char_count(node, '/') != 2)
+ char type[BUS_ID_SIZE];
+ const char *p;
+
+ /* FIXME: wouldn't need this if we could limit watch depth. */
+ if (char_count(node, '/') != bus->levels)
return;
+
+ /* backend/<type>/... or device/<type>/... */
+ p = strchr(node, '/') + 1;
+ snprintf(type, BUS_ID_SIZE, "%.*s", strcspn(p, "/"), p);
+ type[BUS_ID_SIZE-1] = '\0';
/* Created or deleted? */
exists = xenbus_exists(node, "");
-
- p = strchr(node, '/') + 1;
- if (strlen(p) + 1 > BUS_ID_SIZE) {
- printk("Device for node %s is too big!\n", node);
- return;
- }
- /* Bus ID is name with / changed to - */
- strcpy(busid, p);
- *strchr(busid, '/') = '-';
-
- dev = xenbus_device_find(busid);
- printk("xenbus: device %s %s\n", busid, dev ? "exists" : "new");
+ dev = xenbus_device_find(node, &bus->bus);
+
+ printk("xenbus: device %s %s\n", node, dev ? "exists" : "new");
if (dev && !exists) {
- printk("xenbus: Unregistering device %s\n", busid);
- /* FIXME: free? */
+ printk("xenbus: Unregistering device %s\n", node);
device_unregister(&dev->dev);
} else if (!dev && exists) {
- printk("xenbus: Adding device %s\n", busid);
- /* Hack bus id back into two strings. */
- *strrchr(busid, '-') = '\0';
- xenbus_probe_device("device", busid, busid+strlen(busid)+1);
+ printk("xenbus: Adding device %s\n", node);
+ xenbus_probe_node(bus, type, node);
} else
- printk("xenbus: strange, %s already %s\n", busid,
+ printk("xenbus: strange, %s already %s\n", node,
exists ? "exists" : "gone");
if (dev)
put_device(&dev->dev);
}
+static void frontend_changed(struct xenbus_watch *watch, const char *node)
+{
+ dev_changed(node, &xenbus_frontend);
+}
+
+static void backend_changed(struct xenbus_watch *watch, const char *node)
+{
+ dev_changed(node, &xenbus_backend);
+}
+
/* We watch for devices appearing and vanishing. */
-static struct xenbus_watch dev_watch = {
+static struct xenbus_watch fe_watch = {
/* FIXME: Ideally we'd only watch for changes 2 levels deep... */
.node = "device",
- .callback = dev_changed,
+ .callback = frontend_changed,
};
+
+static struct xenbus_watch be_watch = {
+ .node = "backend",
+ .callback = backend_changed,
+};
+
+static int suspend_dev(struct device *dev, void *data)
+{
+ int err = 0;
+ struct xenbus_driver *drv = to_xenbus_driver(dev->driver);
+ struct xenbus_device *xdev
+ = container_of(dev, struct xenbus_device, dev);
+
+ if (drv->suspend)
+ err = drv->suspend(xdev);
+ if (err)
+ printk("xenbus: suspend %s failed: %i\n", dev->bus_id, err);
+ return 0;
+}
+
+static int resume_dev(struct device *dev, void *data)
+{
+ int err = 0;
+ struct xenbus_driver *drv = to_xenbus_driver(dev->driver);
+ struct xenbus_device *xdev
+ = container_of(dev, struct xenbus_device, dev);
+
+ if (drv->resume)
+ err = drv->resume(xdev);
+ if (err)
+ printk("xenbus: resume %s failed: %i\n", dev->bus_id, err);
+ return 0;
+}
void xenbus_suspend(void)
{
/* We keep lock, so no comms can happen as page moves. */
down(&xenbus_lock);
+ bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_dev);
+ bus_for_each_dev(&xenbus_backend.bus, NULL, NULL, suspend_dev);
xb_suspend_comms();
}
@@ -310,6 +531,8 @@
{
xb_init_comms();
reregister_xenbus_watches();
+ bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, resume_dev);
+ bus_for_each_dev(&xenbus_backend.bus, NULL, NULL, resume_dev);
up(&xenbus_lock);
}
@@ -354,30 +577,21 @@
}
down(&xenbus_lock);
- err = notifier_call_chain(&xenstore_chain, 0, 0);
- up(&xenbus_lock);
-
- if (err == NOTIFY_BAD) {
- printk("%s: calling xenstore notify chain failed\n",
- __FUNCTION__);
- return -EINVAL;
- }
-
- err = 0;
-
- down(&xenbus_lock);
/* Enumerate devices in xenstore. */
- xenbus_probe_devices("device");
+ xenbus_probe_devices(&xenbus_frontend);
+ xenbus_probe_devices(&xenbus_backend);
/* Watch for changes. */
- register_xenbus_watch(&dev_watch);
+ register_xenbus_watch(&fe_watch);
+ register_xenbus_watch(&be_watch);
up(&xenbus_lock);
return 0;
}
static int __init xenbus_probe_init(void)
{
- bus_register(&xenbus_type);
-
+ bus_register(&xenbus_frontend.bus);
+ bus_register(&xenbus_backend.bus);
+
if (!xen_start_info.store_evtchn)
return 0;
diff -r 18f04796ea89 -r 9471090bb8ec
linux-2.6-xen-sparse/include/asm-xen/xenbus.h
--- a/linux-2.6-xen-sparse/include/asm-xen/xenbus.h Wed Aug 17 12:30:04 2005
+++ b/linux-2.6-xen-sparse/include/asm-xen/xenbus.h Thu Aug 18 18:54:38 2005
@@ -61,9 +61,11 @@
char *name;
struct module *owner;
const struct xenbus_device_id *ids;
- int (*probe) (struct xenbus_device * dev,
- const struct xenbus_device_id * id);
- int (*remove) (struct xenbus_device * dev);
+ int (*probe)(struct xenbus_device *dev,
+ const struct xenbus_device_id *id);
+ int (*remove)(struct xenbus_device *dev);
+ int (*suspend)(struct xenbus_device *dev);
+ int (*resume)(struct xenbus_device *dev);
struct device_driver driver;
};
@@ -72,7 +74,8 @@
return container_of(drv, struct xenbus_driver, driver);
}
-int xenbus_register_driver(struct xenbus_driver *drv);
+int xenbus_register_device(struct xenbus_driver *drv);
+int xenbus_register_backend(struct xenbus_driver *drv);
void xenbus_unregister_driver(struct xenbus_driver *drv);
/* Caller must hold this lock to call these functions: it's also held
@@ -123,6 +126,9 @@
void unregister_xenbus_watch(struct xenbus_watch *watch);
void reregister_xenbus_watches(void);
+/* For backends, does lookup on uuid (up to /). Returns domid, or -errno. */
+int xenbus_uuid_to_domid(const char *uuid);
+
/* Called from xen core code. */
void xenbus_suspend(void);
void xenbus_resume(void);
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