mac80211: add a single-transaction driver op to switch contexts

In some cases, when the driver is already using all the channel
contexts it can handle at once, we have to do an in-place switch
(ie. we cannot afford using an extra context temporarily for the
transaction).  But some drivers may not support switching the channel
context assigned to a vif on the fly (ie. without unassigning and
assigning it) while others may only work if the context is changed on
the fly, without unassigning it first.

To allow these different scenarios, add a new driver operation that
let's the driver decide how to handle an in-place switch.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 696ef78b1fb7..bd782dcffcc7 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1048,6 +1048,59 @@ static inline void drv_unassign_vif_chanctx(struct ieee80211_local *local,
 	trace_drv_return_void(local);
 }
 
+static inline int
+drv_switch_vif_chanctx(struct ieee80211_local *local,
+		       struct ieee80211_vif_chanctx_switch *vifs,
+		       int n_vifs,
+		       enum ieee80211_chanctx_switch_mode mode)
+{
+	int ret = 0;
+	int i;
+
+	if (!local->ops->switch_vif_chanctx)
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < n_vifs; i++) {
+		struct ieee80211_chanctx *new_ctx =
+			container_of(vifs[i].new_ctx,
+				     struct ieee80211_chanctx,
+				     conf);
+		struct ieee80211_chanctx *old_ctx =
+			container_of(vifs[i].old_ctx,
+				     struct ieee80211_chanctx,
+				     conf);
+
+		WARN_ON_ONCE(!old_ctx->driver_present);
+		WARN_ON_ONCE((mode == CHANCTX_SWMODE_SWAP_CONTEXTS &&
+			      new_ctx->driver_present) ||
+			     (mode == CHANCTX_SWMODE_REASSIGN_VIF &&
+			      !new_ctx->driver_present));
+	}
+
+	trace_drv_switch_vif_chanctx(local, vifs, n_vifs, mode);
+	ret = local->ops->switch_vif_chanctx(&local->hw,
+					     vifs, n_vifs, mode);
+	trace_drv_return_int(local, ret);
+
+	if (!ret && mode == CHANCTX_SWMODE_SWAP_CONTEXTS) {
+		for (i = 0; i < n_vifs; i++) {
+			struct ieee80211_chanctx *new_ctx =
+				container_of(vifs[i].new_ctx,
+					     struct ieee80211_chanctx,
+					     conf);
+			struct ieee80211_chanctx *old_ctx =
+				container_of(vifs[i].old_ctx,
+					     struct ieee80211_chanctx,
+					     conf);
+
+			new_ctx->driver_present = true;
+			old_ctx->driver_present = false;
+		}
+	}
+
+	return ret;
+}
+
 static inline int drv_start_ap(struct ieee80211_local *local,
 			       struct ieee80211_sub_if_data *sdata)
 {