genetlink: Optimize and one bug fix in genl_generate_id()
1. GENL_MIN_ID is a valid id -> no need to start at
GENL_MIN_ID + 1.
2. Avoid going through the ids two times: If we start at
GENL_MIN_ID+1 (*or bigger*) and all ids are over!, the
code iterates through the list twice (*or lesser*).
3. Simplify code - no need to start at idx=0 which gets
reset to GENL_MIN_ID.
Patch on net-next-2.6. Reboot test shows that first id
passed to genl_register_family was 16, next two were
GENL_ID_GENERATE and genl_generate_id returned 17 & 18
(user level testing of same code shows expected values
across entire range of MIN/MAX).
Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index ddfdb7d..d07ecda 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -97,25 +97,17 @@
*/
static inline u16 genl_generate_id(void)
{
- static u16 id_gen_idx;
- int overflowed = 0;
+ static u16 id_gen_idx = GENL_MIN_ID;
+ int i;
- do {
- if (id_gen_idx == 0)
+ for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
+ if (!genl_family_find_byid(id_gen_idx))
+ return id_gen_idx;
+ if (++id_gen_idx > GENL_MAX_ID)
id_gen_idx = GENL_MIN_ID;
+ }
- if (++id_gen_idx > GENL_MAX_ID) {
- if (!overflowed) {
- overflowed = 1;
- id_gen_idx = 0;
- continue;
- } else
- return 0;
- }
-
- } while (genl_family_find_byid(id_gen_idx));
-
- return id_gen_idx;
+ return 0;
}
static struct genl_multicast_group notify_grp;