cfg80211/mac80211: allow management TX to not wait for ACK

For probe responses it can be useful to not wait for ACK to
avoid retransmissions if the station that sent the probe is
already on the next channel, so allow userspace to request
not caring about the ACK with a new nl80211 flag.

Since mac80211 needs to be updated for the new function
prototype anyway implement it right away -- it's just a
few lines of code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 09474ab..165e16f 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1151,6 +1151,11 @@
  *	with support for the features listed in this attribute, see
  *	&enum nl80211_ap_sme_features.
  *
+ * @NL80211_ATTR_DONT_WAIT_FOR_ACK: Used with %NL80211_CMD_FRAME, this tells
+ *	the driver to not wait for an acknowledgement. Note that due to this,
+ *	it will also not give a status callback nor return a cookie. This is
+ *	mostly useful for probe responses to save airtime.
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1381,6 +1386,8 @@
 
 	NL80211_ATTR_DEVICE_AP_SME,
 
+	NL80211_ATTR_DONT_WAIT_FOR_ACK,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,