Current implementation of __dev_alloc_name uses a custom bitmap of
a single page to iterate network device id's and allocate an unused id.
This leads to a upper limit of 8 * PAGE_SIZE network device id's (for
each name format i.e eth0).
This patch uses the kernel's IDA as a replacement to the page based
bitmap. This has the effect of simplifying the code and removing
the upper limit.
Signed-off-by: Tobin C. Harding <m...@tobin.cc>
---
net/core/dev.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 29101c9..b16ea84 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1025,39 +1025,31 @@ static int __dev_alloc_name(struct net *net, const char
*name, char *buf)
{
int i = 0;
const char *p;
- const int max_netdevices = 8*PAGE_SIZE;
- unsigned long *inuse;
struct net_device *d;
+ DEFINE_IDA(ida);
+ const int end = 0;
p = strnchr(name, IFNAMSIZ-1, '%');
if (p) {
- /*
- * Verify the string as this thing may have come from
+ /* Verify the string as this thing may have come from
* the user. There must be either one "%d" and no other "%"
* characters.
*/
if (p[1] != 'd' || strchr(p + 2, '%'))
return -EINVAL;
- /* Use one page as a bit array of possible slots */
- inuse = (unsigned long *) get_zeroed_page(GFP_ATOMIC);
- if (!inuse)
- return -ENOMEM;
-
for_each_netdev(net, d) {
if (!sscanf(d->name, name, &i))
continue;
- if (i < 0 || i >= max_netdevices)
+ if (i < 0)
continue;
/* avoid cases where sscanf is not exact inverse of
printf */
snprintf(buf, IFNAMSIZ, name, i);
if (!strncmp(buf, d->name, IFNAMSIZ))
- set_bit(i, inuse);
+ ida_simple_get(&ida, i, end, GFP_KERNEL);
}
-
- i = find_first_zero_bit(inuse, max_netdevices);
- free_page((unsigned long) inuse);
+ i = ida_simple_get(&ida, 0, end, GFP_KERNEL);
}
if (buf != name)
--
2.7.4
