From: Eric W. Biederman <[EMAIL PROTECTED]> - unquoted
When forcibly changing the network namespace of a device
I need something that can generate a name for the device
in the new namespace without overwriting the old name.
__dev_alloc_name provides me that functionality.
Signed-off-by: Eric W. Biederman <[EMAIL PROTECTED]>
---
net/core/dev.c | 44 +++++++++++++++++++++++++++++++++-----------
1 files changed, 33 insertions(+), 11 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 32fe905..fc0d2af 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -655,9 +655,10 @@ int dev_valid_name(const char *name)
}
/**
- * dev_alloc_name - allocate a name for a device
- * @dev: device
+ * __dev_alloc_name - allocate a name for a device
+ * @net: network namespace to allocate the device name in
* @name: name format string
+ * @buf: scratch buffer and result name string
*
* Passed a format string - eg "lt%d" it will try and find a suitable
* id. It scans list of devices to build up a free map, then chooses
@@ -668,18 +669,13 @@ int dev_valid_name(const char *name)
* Returns the number of the unit assigned or a negative errno code.
*/
-int dev_alloc_name(struct net_device *dev, const char *name)
+static int __dev_alloc_name(net_t net, const char *name, char buf[IFNAMSIZ])
{
int i = 0;
- char buf[IFNAMSIZ];
const char *p;
const int max_netdevices = 8*PAGE_SIZE;
long *inuse;
struct net_device *d;
- net_t net;
-
- BUG_ON(null_net(dev->nd_net));
- net = dev->nd_net;
p = strnchr(name, IFNAMSIZ-1, '%');
if (p) {
@@ -713,10 +709,8 @@ int dev_alloc_name(struct net_device *dev, const char
*name)
}
snprintf(buf, sizeof(buf), name, i);
- if (!__dev_get_by_name(net, buf)) {
- strlcpy(dev->name, buf, IFNAMSIZ);
+ if (!__dev_get_by_name(net, buf))
return i;
- }
/* It is possible to run out of possible slots
* when the name is long and there isn't enough space left
@@ -725,6 +719,34 @@ int dev_alloc_name(struct net_device *dev, const char
*name)
return -ENFILE;
}
+/**
+ * dev_alloc_name - allocate a name for a device
+ * @dev: device
+ * @name: name format string
+ *
+ * Passed a format string - eg "lt%d" it will try and find a suitable
+ * id. It scans list of devices to build up a free map, then chooses
+ * the first empty slot. The caller must hold the dev_base or rtnl lock
+ * while allocating the name and adding the device in order to avoid
+ * duplicates.
+ * Limited to bits_per_byte * page size devices (ie 32K on most platforms).
+ * Returns the number of the unit assigned or a negative errno code.
+ */
+
+int dev_alloc_name(struct net_device *dev, const char *name)
+{
+ char buf[IFNAMSIZ];
+ net_t net;
+ int ret;
+
+ BUG_ON(null_net(dev->nd_net));
+ net = dev->nd_net;
+ ret = __dev_alloc_name(net, name, buf);
+ if (ret >= 0)
+ strlcpy(dev->name, buf, IFNAMSIZ);
+ return ret;
+}
+
/**
* dev_change_name - change name of a device
--
1.4.4.1.g278f
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