mac80211: Skip tailroom reservation for full HW-crypto devices

In xmit path, devices that do full hardware crypto (including
TKIP MMIC) need no tailroom. For such devices, tailroom
reservation can be skipped if all the keys are programmed into
the hardware (i.e software crypto is not used for any of the
keys) and none of the keys wants software to generate Michael
MIC.

Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index af3c56482c80..ca3c626b011a 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -101,6 +101,10 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 
         if (!ret) {
                 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
+
+                if (!(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC))
+                        key->local->crypto_tx_tailroom_needed_cnt--;
+
                 return 0;
         }
 
@@ -156,6 +160,9 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
                           key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
 
         key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
+
+        if (!(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC))
+                key->local->crypto_tx_tailroom_needed_cnt++;
 }
 
 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
@@ -388,8 +395,10 @@ static void __ieee80211_key_destroy(struct ieee80211_key *key)
                 ieee80211_aes_key_free(key->u.ccmp.tfm);
         if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
                 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
-        if (key->local)
+        if (key->local) {
                 ieee80211_debugfs_key_remove(key);
+                key->local->crypto_tx_tailroom_needed_cnt--;
+        }
 
         kfree(key);
 }
@@ -451,6 +460,8 @@ int ieee80211_key_link(struct ieee80211_key *key,
 
         ieee80211_debugfs_key_add(key);
 
+        key->local->crypto_tx_tailroom_needed_cnt++;
+
         ret = ieee80211_key_enable_hw_accel(key);
 
         mutex_unlock(&sdata->local->key_mtx);
@@ -492,8 +503,12 @@ void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
 
         mutex_lock(&sdata->local->key_mtx);
 
-        list_for_each_entry(key, &sdata->key_list, list)
+        sdata->local->crypto_tx_tailroom_needed_cnt = 0;
+
+        list_for_each_entry(key, &sdata->key_list, list) {
+                sdata->local->crypto_tx_tailroom_needed_cnt++;
                 ieee80211_key_enable_hw_accel(key);
+        }
 
         mutex_unlock(&sdata->local->key_mtx);
 }