[PATCH] mac80211: only alloc mem if a station doesnt exist yet

[PATCH] mac80211: only alloc mem if a station doesnt exist yet

[Koen Vandeputte]

This speeds up the function in case a station already exists by avoiding
calling an expensive kzalloc just to free it again after the next check.

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
---
 net/mac80211/sta_info.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 1711bae..0a42e6e 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -513,23 +513,23 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
 {
 	struct ieee80211_local *local = sta->local;
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
-	struct station_info *sinfo;
+	struct station_info *sinfo = NULL;
 	int err = 0;
 
 	lockdep_assert_held(&local->sta_mtx);
 
-	sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL);
-	if (!sinfo) {
-		err = -ENOMEM;
-		goto out_err;
-	}
-
 	/* check if STA exists already */
 	if (sta_info_get_bss(sdata, sta->sta.addr)) {
 		err = -EEXIST;
 		goto out_err;
 	}
 
+	sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL);
+	if (!sinfo) {
+		err = -ENOMEM;
+		goto out_err;
+	}
+
 	local->num_sta++;
 	local->sta_generation++;
 	smp_mb();
-- 
2.7.4

Re: [PATCH] mac80211: only alloc mem if a station doesnt exist yet

[Johannes Berg]

On Wed, 2016-12-14 at 17:28 +0100, Koen Vandeputte wrote:
> This speeds up the function in case a station already exists by
> avoiding
> calling an expensive kzalloc just to free it again after the next
> check.

It's not like this is called often, but yeah - still makes sense.

Applied.

johannes