mac80211: Use the right headroom size for mesh mgmt frames

Use local->tx_headroom instad of local->hw.extra_tx_headroom.
local->tx_headroom is the max of hw.extra_tx_headroom required by the
driver and the headroom required by mac80211 for status reporting. On
drivers where hw.extra_tx_headroom is smaller than what mac80211
requires (e.g. ath5k), we would not reserve sufficient buffer space to
report tx status.

Also, don't reserve local->tx_headroom + local->hw.extra_tx_headroom.

Reported-by: Simon Morgenthaler <[e-mail]>
Reported-by: Kai Scharwies <[e-mail]>
Signed-off-by: Javier Cardona <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

net/mac80211/mesh_hwmp.c

···
 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 		      sizeof(mgmt->u.action.u.mesh_action);
 
-	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
+	skb = dev_alloc_skb(local->tx_headroom +
 			    hdr_len +
 			    2 + 37); /* max HWMP IE */
 	if (!skb)
 		return -1;
-	skb_reserve(skb, local->hw.extra_tx_headroom);
+	skb_reserve(skb, local->tx_headroom);
 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 	memset(mgmt, 0, hdr_len);
 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
···
 	if (time_before(jiffies, ifmsh->next_perr))
 		return -EAGAIN;
 
-	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
+	skb = dev_alloc_skb(local->tx_headroom +
 			    hdr_len +
 			    2 + 15 /* PERR IE */);
 	if (!skb)
 		return -1;
-	skb_reserve(skb, local->tx_headroom + local->hw.extra_tx_headroom);
+	skb_reserve(skb, local->tx_headroom);
 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 	memset(mgmt, 0, hdr_len);
 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |

net/mac80211/mesh_plink.c

···
 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 		      sizeof(mgmt->u.action.u.self_prot);
 
-	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
+	skb = dev_alloc_skb(local->tx_headroom +
 			    hdr_len +
 			    2 + /* capability info */
 			    2 + /* AID */
···
 			    sdata->u.mesh.ie_len);
 	if (!skb)
 		return -1;
-	skb_reserve(skb, local->hw.extra_tx_headroom);
+	skb_reserve(skb, local->tx_headroom);
 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 	memset(mgmt, 0, hdr_len);
 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |