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genetlink: Optimize and one bug fix in genl_generate_id()

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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>
This commit is contained in:
Krishna Kumar
2009-10-14 19:55:07 +00:00
committed by David S. Miller
parent 93860b08e3
commit 988ade6b8e
1 changed files with 8 additions and 16 deletions
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24
net/netlink/genetlink.c
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@@ -97,25 +97,17 @@ static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
*/ */
static inline u16 genl_generate_id(void) static inline u16 genl_generate_id(void)
{ {
static u16 id_gen_idx; static u16 id_gen_idx = GENL_MIN_ID;
int overflowed = 0; int i;
do { for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
if (id_gen_idx == 0) 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; id_gen_idx = GENL_MIN_ID;
}
if (++id_gen_idx > GENL_MAX_ID) { return 0;
if (!overflowed) {
overflowed = 1;
id_gen_idx = 0;
continue;
} else
return 0;
}
} while (genl_family_find_byid(id_gen_idx));
return id_gen_idx;
} }
static struct genl_multicast_group notify_grp; static struct genl_multicast_group notify_grp;