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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Tidy up use of environment variables in xenbus-hotplug interaction.
# HG changeset patch
# User emellor@xxxxxxxxxxxxxxxxxxxxxx
# Node ID 5f574f9cb4bd2b5eebd98ce6fc43ce0c33d7b1d4
# Parent 91046e4a49dd4ab33451d7fee479a450a32d8684
Tidy up use of environment variables in xenbus-hotplug interaction.
I've changed this to only write "backend" (xenbus_backend.root) into
XENBUS_BASE_PATH. After appending XENBUS_TYPE (also exported) you can
construct the "base path" easily in the scripts. I've completely
removed writing XENBUS_FRONTEND_ID in favour of reading it from the
store at "$XENBUS_PATH/frontend-id".
Avoid re-reading the store over and over for the frontend domain's vm-path.
The patch also fixes a memory leak in backend_bus_id where we
leak the memory referenced by frontend if the function succeeds.
This work is by Christian Limpach.
Signed-off-by: Ewan Mellor <ewan@xxxxxxxxxxxxx>
diff -r 91046e4a49dd -r 5f574f9cb4bd
linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c Wed Dec 7
11:51:31 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c Wed Dec 7
11:57:26 2005
@@ -59,8 +59,6 @@
#define streq(a, b) (strcmp((a), (b)) == 0)
-static char *kasprintf(const char *fmt, ...);
-
static struct notifier_block *xenstore_chain;
/* If something in array of ids matches this device, return it. */
@@ -209,14 +207,13 @@
return err;
if (strlen(frontend) == 0)
err = -ERANGE;
-
if (!err && !xenbus_exists(NULL, frontend, ""))
err = -ENOENT;
- if (err) {
- kfree(frontend);
+ kfree(frontend);
+
+ if (err)
return err;
- }
if (snprintf(bus_id, BUS_ID_SIZE,
"%.*s-%i-%s", typelen, type, domid, devid) >= BUS_ID_SIZE)
@@ -225,69 +222,7 @@
}
static int xenbus_hotplug_backend(struct device *dev, char **envp,
- int num_envp, char *buffer, int buffer_size)
-{
- struct xenbus_device *xdev;
- struct xenbus_driver *drv = NULL;
- int i = 0;
- int length = 0;
- char *basepath_end;
- char *frontend_id;
-
- DPRINTK("");
-
- if (dev == NULL)
- return -ENODEV;
-
- xdev = to_xenbus_device(dev);
- if (xdev == NULL)
- return -ENODEV;
-
- if (dev->driver)
- drv = to_xenbus_driver(dev->driver);
-
- /* stuff we want to pass to /sbin/hotplug */
- add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "XENBUS_TYPE=%s", xdev->devicetype);
-
- add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "XENBUS_PATH=%s", xdev->nodename);
-
- add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "XENBUS_BASE_PATH=%s", xdev->nodename);
-
- basepath_end = strrchr(envp[i - 1], '/');
- length -= strlen(basepath_end);
- *basepath_end = '\0';
- basepath_end = strrchr(envp[i - 1], '/');
- length -= strlen(basepath_end);
- *basepath_end = '\0';
-
- basepath_end++;
- frontend_id = kmalloc(strlen(basepath_end) + 1, GFP_KERNEL);
- strcpy(frontend_id, basepath_end);
- add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "XENBUS_FRONTEND_ID=%s", frontend_id);
- kfree(frontend_id);
-
- /* terminate, set to next free slot, shrink available space */
- envp[i] = NULL;
- envp = &envp[i];
- num_envp -= i;
- buffer = &buffer[length];
- buffer_size -= length;
-
- if (drv && drv->hotplug)
- return drv->hotplug(xdev, envp, num_envp, buffer,
- buffer_size);
-
- return 0;
-}
-
+ int num_envp, char *buffer, int buffer_size);
static int xenbus_probe_backend(const char *type, const char *domid);
static struct xen_bus_type xenbus_backend = {
.root = "backend",
@@ -304,6 +239,52 @@
},
};
+static int xenbus_hotplug_backend(struct device *dev, char **envp,
+ int num_envp, char *buffer, int buffer_size)
+{
+ struct xenbus_device *xdev;
+ struct xenbus_driver *drv;
+ int i = 0;
+ int length = 0;
+
+ DPRINTK("");
+
+ if (dev == NULL)
+ return -ENODEV;
+
+ xdev = to_xenbus_device(dev);
+ if (xdev == NULL)
+ return -ENODEV;
+
+ /* stuff we want to pass to /sbin/hotplug */
+ add_hotplug_env_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "XENBUS_TYPE=%s", xdev->devicetype);
+
+ add_hotplug_env_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "XENBUS_PATH=%s", xdev->nodename);
+
+ add_hotplug_env_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "XENBUS_BASE_PATH=%s", xenbus_backend.root);
+
+ /* terminate, set to next free slot, shrink available space */
+ envp[i] = NULL;
+ envp = &envp[i];
+ num_envp -= i;
+ buffer = &buffer[length];
+ buffer_size -= length;
+
+ if (dev->driver) {
+ drv = to_xenbus_driver(dev->driver);
+ if (drv && drv->hotplug)
+ return drv->hotplug(xdev, envp, num_envp, buffer,
+ buffer_size);
+ }
+
+ return 0;
+}
static void otherend_changed(struct xenbus_watch *watch,
const char **vec, unsigned int len)
diff -r 91046e4a49dd -r 5f574f9cb4bd tools/examples/block
--- a/tools/examples/block Wed Dec 7 11:51:31 2005
+++ b/tools/examples/block Wed Dec 7 11:57:26 2005
@@ -89,12 +89,12 @@
fi
done
- for dom in $(xenstore-list "$XENBUS_BASE_PATH")
+ local base_path="$XENBUS_BASE_PATH/$XENBUS_TYPE"
+ for dom in $(xenstore-list "$base_path")
do
- for dev in $(xenstore-list "$XENBUS_BASE_PATH/$dom")
+ for dev in $(xenstore-list "$base_path/$dom")
do
- d=$(xenstore_read_default \
- "$XENBUS_BASE_PATH/$dom/$dev/physical-device" "")
+ d=$(xenstore_read_default "$base_path/$dom/$dev/physical-device" "")
if [ "$d" == "$devmm" ]
then
@@ -106,7 +106,7 @@
return
fi
else
- local m=$(xenstore_read "$XENBUS_BASE_PATH/$dom/$dev/mode")
+ local m=$(xenstore_read "$base_path/$dom/$dev/mode")
m=$(canonicalise_mode "$m")
if [ "$m" == 'w' ]
@@ -128,12 +128,10 @@
same_vm()
{
- local thisdom="$XENBUS_FRONTEND_ID"
local otherdom="$1"
- local thisvm=$(xenstore-read "/local/domain/$thisdom/vm")
local othervm=$(xenstore-read "/local/domain/$otherdom/vm")
- [ "$thisvm" == "$othervm" ]
+ [ "$FRONTEND_UUID" == "$othervm" ]
}
@@ -240,6 +238,9 @@
case $t in
phy)
dev=$(expand_dev $p)
+ FRONTEND_ID=$(xenstore_read "$XENBUS_PATH/frontend-id")
+ FRONTEND_UUID=$(xenstore_read_default \
+ "/local/domain/$FRONTEND_ID/vm" 'unknown')
claim_lock "block"
check_device_sharing "$dev" "$mode"
write_dev "$dev"
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