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>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 8d6d6e3d95da409e6c72f286338411e38d548893..9e3b4f0f31bd6886a7fa073f29c1cbab19976a8b 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -766,6 +766,9 @@ struct ieee80211_local {
 
        int tx_headroom; /* required headroom for hardware/radiotap */
 
+       /* count for keys needing tailroom space allocation */
+       int crypto_tx_tailroom_needed_cnt;
+
        /* Tasklet and skb queue to process calls from IRQ mode. All frames
         * added to skb_queue will be processed, but frames in
         * skb_queue_unreliable may be dropped if the total length of these

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index af3c56482c80b519d97d166373c05860b47f28dd..ca3c626b011acec358c0d4f3a73aa9892eb057f9 100644 (file)
--- 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);
 }

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index a2043e40549365f2ab1c41e767a4cc00127ae204..e3e3aa173af07d324d5fb745c76a1d28fc057985 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1476,12 +1476,7 @@ static int ieee80211_skb_resize(struct ieee80211_local *local,
 {
        int tail_need = 0;
 
-       /*
-        * This could be optimised, devices that do full hardware
-        * crypto (including TKIP MMIC) need no tailroom... But we
-        * have no drivers for such devices currently.
-        */
-       if (may_encrypt) {
+       if (may_encrypt && local->crypto_tx_tailroom_needed_cnt) {
                tail_need = IEEE80211_ENCRYPT_TAILROOM;
                tail_need -= skb_tailroom(skb);
                tail_need = max_t(int, tail_need, 0);