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net: don't use input buffer of __dev_alloc_name() as a scratch space

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Callers of __dev_alloc_name() want to pass dev->name as
the output buffer. Make __dev_alloc_name() not clobber
that buffer on failure, and remove the workarounds
in callers.

dev_alloc_name_ns() is now completely unnecessary.

The extra strscpy() added here will be gone by the end
of the patch series.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231023152346.3639749-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2023-10-23 08:23:41 -07:00
parent fb1c535b13
commit bd07063dd1
1 changed files with 8 additions and 25 deletions
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33
net/core/dev.c
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@ -1057,7 +1057,7 @@ EXPORT_SYMBOL(dev_valid_name);
* __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
* @res: 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
@ -1068,13 +1068,14 @@ EXPORT_SYMBOL(dev_valid_name);
* Returns the number of the unit assigned or a negative errno code.
*/
static int __dev_alloc_name(struct net *net, const char *name, char *buf)
static int __dev_alloc_name(struct net *net, const char *name, char *res)
{
int i = 0;
const char *p;
const int max_netdevices = 8*PAGE_SIZE;
unsigned long *inuse;
struct net_device *d;
char buf[IFNAMSIZ];
if (!dev_valid_name(name))
return -EINVAL;
@ -1124,8 +1125,10 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf)
}
snprintf(buf, IFNAMSIZ, name, i);
if (!netdev_name_in_use(net, buf))
if (!netdev_name_in_use(net, buf)) {
strscpy(res, buf, IFNAMSIZ);
return i;
}
/* It is possible to run out of possible slots
* when the name is long and there isn't enough space left
@ -1154,20 +1157,6 @@ static int dev_prep_valid_name(struct net *net, struct net_device *dev,
return 0;
}
static int dev_alloc_name_ns(struct net *net,
struct net_device *dev,
const char *name)
{
char buf[IFNAMSIZ];
int ret;
BUG_ON(!net);
ret = __dev_alloc_name(net, name, buf);
if (ret >= 0)
strscpy(dev->name, buf, IFNAMSIZ);
return ret;
}
/**
* dev_alloc_name - allocate a name for a device
* @dev: device
@ -1184,20 +1173,14 @@ static int dev_alloc_name_ns(struct net *net,
int dev_alloc_name(struct net_device *dev, const char *name)
{
return dev_alloc_name_ns(dev_net(dev), dev, name);
return __dev_alloc_name(dev_net(dev), name, dev->name);
}
EXPORT_SYMBOL(dev_alloc_name);
static int dev_get_valid_name(struct net *net, struct net_device *dev,
const char *name)
{
char buf[IFNAMSIZ];
int ret;
ret = dev_prep_valid_name(net, dev, name, buf);
if (ret >= 0)
strscpy(dev->name, buf, IFNAMSIZ);
return ret;
return dev_prep_valid_name(net, dev, name, dev->name);
}
/**