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Date: Tue, 17 Nov 2009 22:33:53 +0200
From: Octavian Purdila <opurdila@...acom.com>
To: Stephen Hemminger <shemminger@...tta.com>
Cc: netdev@...r.kernel.org
Subject: Re: [net-next-2.6 PATCH] net: device name allocation cleanups
On Tuesday 17 November 2009 19:01:57 you wrote:
> You have merged the dev_alloc_name into all the registration paths.
> Before it was possible for device to call register_netdevice with a name
> with a % in it. Only if it did dev_alloc_name or register_netdev would
> the %d be interpreted.
>
> So this patch causes a change which may be visible in user space.
Oops, didn't saw that coming :) How about this one?
(tested all code paths except the dev_change_net_namespace)
[net-next-2.6 PATCH] net: device name allocation cleanups
Signed-off-by: Octavian Purdila <opurdila@...acom.com>
---
net/core/dev.c | 73 +++++++++++++++++++++----------------------------------
1 files changed, 28 insertions(+), 45 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 4b24d79..eec13de 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -893,7 +893,8 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
free_page((unsigned long) inuse);
}
- snprintf(buf, IFNAMSIZ, name, i);
+ if (buf != name)
+ snprintf(buf, IFNAMSIZ, name, i);
if (!__dev_get_by_name(net, buf))
return i;
@@ -933,6 +934,25 @@ int dev_alloc_name(struct net_device *dev, const char *name)
}
EXPORT_SYMBOL(dev_alloc_name);
+static int dev_get_valid_name(struct net *net, const char *name, char *buf,
+ int fmt)
+{
+ if (!dev_valid_name(name))
+ return -EINVAL;
+
+ if (fmt) {
+ if (strchr(name, '%'))
+ return __dev_alloc_name(net, name, buf);
+ }
+
+ if (__dev_get_by_name(net, name))
+ return -EEXIST;
+ else
+ if (buf != name)
+ strlcpy(buf, name, IFNAMSIZ);
+
+ return 0;
+}
/**
* dev_change_name - change name of a device
@@ -956,22 +976,14 @@ int dev_change_name(struct net_device *dev, const char *newname)
if (dev->flags & IFF_UP)
return -EBUSY;
- if (!dev_valid_name(newname))
- return -EINVAL;
-
if (strncmp(newname, dev->name, IFNAMSIZ) == 0)
return 0;
memcpy(oldname, dev->name, IFNAMSIZ);
- if (strchr(newname, '%')) {
- err = dev_alloc_name(dev, newname);
- if (err < 0)
- return err;
- } else if (__dev_get_by_name(net, newname))
- return -EEXIST;
- else
- strlcpy(dev->name, newname, IFNAMSIZ);
+ err = dev_get_valid_name(net, newname, dev->name, 1);
+ if (err < 0)
+ return err;
rollback:
/* For now only devices in the initial network namespace
@@ -4864,8 +4876,6 @@ EXPORT_SYMBOL(netdev_fix_features);
int register_netdevice(struct net_device *dev)
{
- struct hlist_head *head;
- struct hlist_node *p;
int ret;
struct net *net = dev_net(dev);
@@ -4894,26 +4904,14 @@ int register_netdevice(struct net_device *dev)
}
}
- if (!dev_valid_name(dev->name)) {
- ret = -EINVAL;
+ ret = dev_get_valid_name(net, dev->name, dev->name, 0);
+ if (ret)
goto err_uninit;
- }
dev->ifindex = dev_new_index(net);
if (dev->iflink == -1)
dev->iflink = dev->ifindex;
- /* Check for existence of name */
- head = dev_name_hash(net, dev->name);
- hlist_for_each(p, head) {
- struct net_device *d
- = hlist_entry(p, struct net_device, name_hlist);
- if (!strncmp(d->name, dev->name, IFNAMSIZ)) {
- ret = -EEXIST;
- goto err_uninit;
- }
- }
-
/* Fix illegal checksum combinations */
if ((dev->features & NETIF_F_HW_CSUM) &&
(dev->features & (NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))) {
@@ -5422,8 +5420,6 @@ EXPORT_SYMBOL(unregister_netdev);
int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat)
{
- char buf[IFNAMSIZ];
- const char *destname;
int err;
ASSERT_RTNL();
@@ -5456,20 +5452,11 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
* we can use it in the destination network namespace.
*/
err = -EEXIST;
- destname = dev->name;
- if (__dev_get_by_name(net, destname)) {
+ if (__dev_get_by_name(net, dev->name)) {
/* We get here if we can't use the current device name */
if (!pat)
goto out;
- if (!dev_valid_name(pat))
- goto out;
- if (strchr(pat, '%')) {
- if (__dev_alloc_name(net, pat, buf) < 0)
- goto out;
- destname = buf;
- } else
- destname = pat;
- if (__dev_get_by_name(net, destname))
+ if (dev_get_valid_name(net, pat, dev->name, 1))
goto out;
}
@@ -5505,10 +5492,6 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
/* Actually switch the network namespace */
dev_net_set(dev, net);
- /* Assign the new device name */
- if (destname != dev->name)
- strcpy(dev->name, destname);
-
/* If there is an ifindex conflict assign a new one */
if (__dev_get_by_index(net, dev->ifindex)) {
int iflink = (dev->iflink == dev->ifindex);
--
1.5.6.5
--
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