diff mbox

[v3,03/13] mac80211: prevent chanctx overcommit

Message ID 1396262371-6466-4-git-send-email-michal.kazior@tieto.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Michal Kazior March 31, 2014, 10:39 a.m. UTC 
Do not allocate more channel contexts than a
driver is capable for currently matching interface
combination.

This allows the ieee80211_vif_reserve_chanctx() to
act as a guard against breaking interface
combinations.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 net/mac80211/chan.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 122033d..90cac10 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -9,6 +9,25 @@ 
 #include "ieee80211_i.h"
 #include "driver-ops.h"
 
+static int ieee80211_num_chanctx(struct ieee80211_local *local)
+{
+	struct ieee80211_chanctx *ctx;
+	int num = 0;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(ctx, &local->chanctx_list, list)
+		num++;
+
+	return num;
+}
+
+static bool ieee80211_can_create_new_chanctx(struct ieee80211_local *local)
+{
+	lockdep_assert_held(&local->chanctx_mtx);
+	return ieee80211_num_chanctx(local) < ieee80211_max_num_channels(local);
+}
+
 static enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
 {
 	switch (sta->bandwidth) {
@@ -752,13 +771,16 @@  int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
 			 * context, reserve our current context
 			 */
 			new_ctx = curr_ctx;
-		} else {
+		} else if (ieee80211_can_create_new_chanctx(local)) {
 			/* create a new context and reserve it */
 			new_ctx = ieee80211_new_chanctx(local, chandef, mode);
 			if (IS_ERR(new_ctx)) {
 				ret = PTR_ERR(new_ctx);
 				goto out;
 			}
+		} else {
+			ret = -EBUSY;
+			goto out;
 		}
 	}