mac80211: use skb list for fragments

We are currently linking the skbs by using skb->next
directly. This works, but the preferred way is to use
a struct sk_buff_head instead. That also prepares for
passing that to drivers directly.

While at it I noticed we calculate the duration for
fragments twice -- remove one of them.

Signed-off-by: Johannes Berg <johannes.berg@intel.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 068cc92..f278505 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -142,6 +142,7 @@ typedef unsigned __bitwise__ ieee80211_tx_result;
 
 struct ieee80211_tx_data {
        struct sk_buff *skb;
+       struct sk_buff_head skbs;
        struct ieee80211_local *local;
        struct ieee80211_sub_if_data *sdata;
        struct sta_info *sta;

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 4319883..26a7cfb 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -35,7 +35,8 @@
 
 /* misc utils */
 
-static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr,
+static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
+                                struct sk_buff *skb, int group_addr,
                                 int next_frag_len)
 {
        int rate, mrate, erp, dur, i;
@@ -43,7 +44,7 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr,
        struct ieee80211_local *local = tx->local;
        struct ieee80211_supported_band *sband;
        struct ieee80211_hdr *hdr;
-       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
+       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 
        /* assume HW handles this */
        if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
@@ -75,7 +76,7 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr,
         *   at the highest possible rate belonging to the PHY rates in the
         *   BSSBasicRateSet
         */
-       hdr = (struct ieee80211_hdr *)tx->skb->data;
+       hdr = (struct ieee80211_hdr *)skb->data;
        if (ieee80211_is_ctl(hdr->frame_control)) {
                /* TODO: These control frames are not currently sent by
                 * mac80211, but should they be implemented, this function
@@ -841,11 +842,12 @@ ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
        return TX_CONTINUE;
 }
 
-static int ieee80211_fragment(struct ieee80211_local *local,
+static int ieee80211_fragment(struct ieee80211_tx_data *tx,
                              struct sk_buff *skb, int hdrlen,
                              int frag_threshold)
 {
-       struct sk_buff *tail = skb, *tmp;
+       struct ieee80211_local *local = tx->local;
+       struct sk_buff *tmp;
        int per_fragm = frag_threshold - hdrlen - FCS_LEN;
        int pos = hdrlen + per_fragm;
        int rem = skb->len - hdrlen - per_fragm;
@@ -853,6 +855,8 @@ static int ieee80211_fragment(struct ieee80211_local *local,
        if (WARN_ON(rem < 0))
                return -EINVAL;
 
+       /* first fragment was already added to queue by caller */
+
        while (rem) {
                int fraglen = per_fragm;
 
@@ -865,8 +869,9 @@ static int ieee80211_fragment(struct ieee80211_local *local,
                                    IEEE80211_ENCRYPT_TAILROOM);
                if (!tmp)
                        return -ENOMEM;
-               tail->next = tmp;
-               tail = tmp;
+
+               __skb_queue_tail(&tx->skbs, tmp);
+
                skb_reserve(tmp, local->tx_headroom +
                                 IEEE80211_ENCRYPT_HEADROOM);
                /* copy control information */
@@ -882,6 +887,7 @@ static int ieee80211_fragment(struct ieee80211_local *local,
                pos += fraglen;
        }
 
+       /* adjust first fragment's length */
        skb->len = hdrlen + per_fragm;
        return 0;
 }
@@ -896,6 +902,10 @@ ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
        int hdrlen;
        int fragnum;
 
+       /* no matter what happens, tx->skb moves to tx->skbs */
+       __skb_queue_tail(&tx->skbs, skb);
+       tx->skb = NULL;
+
        if (info->flags & IEEE80211_TX_CTL_DONTFRAG)
                return TX_CONTINUE;
 
@@ -924,21 +934,21 @@ ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
         * of the fragments then we will simply pretend to accept the skb
         * but store it away as pending.
         */
-       if (ieee80211_fragment(tx->local, skb, hdrlen, frag_threshold))
+       if (ieee80211_fragment(tx, skb, hdrlen, frag_threshold))
                return TX_DROP;
 
        /* update duration/seq/flags of fragments */
        fragnum = 0;
-       do {
+
+       skb_queue_walk(&tx->skbs, skb) {
                int next_len;
                const __le16 morefrags = cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
 
                hdr = (void *)skb->data;
                info = IEEE80211_SKB_CB(skb);
 
-               if (skb->next) {
+               if (!skb_queue_is_last(&tx->skbs, skb)) {
                        hdr->frame_control |= morefrags;
-                       next_len = skb->next->len;
                        /*
                         * No multi-rate retries for fragmented frames, that
                         * would completely throw off the NAV at other STAs.
@@ -953,10 +963,9 @@ ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
                        hdr->frame_control &= ~morefrags;
                        next_len = 0;
                }
-               hdr->duration_id = ieee80211_duration(tx, 0, next_len);
                hdr->seq_ctrl |= cpu_to_le16(fragnum & IEEE80211_SCTL_FRAG);
                fragnum++;
-       } while ((skb = skb->next));
+       }
 
        return TX_CONTINUE;
 }
@@ -964,16 +973,16 @@ ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
 static ieee80211_tx_result debug_noinline
 ieee80211_tx_h_stats(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
+       struct sk_buff *skb;
 
        if (!tx->sta)
                return TX_CONTINUE;
 
        tx->sta->tx_packets++;
-       do {
+       skb_queue_walk(&tx->skbs, skb) {
                tx->sta->tx_fragments++;
                tx->sta->tx_bytes += skb->len;
-       } while ((skb = skb->next));
+       }
 
        return TX_CONTINUE;
 }
@@ -1012,21 +1021,25 @@ ieee80211_tx_h_encrypt(struct ieee80211_tx_data *tx)
 static ieee80211_tx_result debug_noinline
 ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
+       struct sk_buff *skb;
        struct ieee80211_hdr *hdr;
        int next_len;
        bool group_addr;
 
-       do {
+       skb_queue_walk(&tx->skbs, skb) {
                hdr = (void *) skb->data;
                if (unlikely(ieee80211_is_pspoll(hdr->frame_control)))
                        break; /* must not overwrite AID */
-               next_len = skb->next ? skb->next->len : 0;
+               if (!skb_queue_is_last(&tx->skbs, skb)) {
+                       struct sk_buff *next = skb_queue_next(&tx->skbs, skb);
+                       next_len = next->len;
+               } else
+                       next_len = 0;
                group_addr = is_multicast_ether_addr(hdr->addr1);
 
                hdr->duration_id =
-                       ieee80211_duration(tx, group_addr, next_len);
-       } while ((skb = skb->next));
+                       ieee80211_duration(tx, skb, group_addr, next_len);
+       }
 
        return TX_CONTINUE;
 }
@@ -1105,6 +1118,7 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
        tx->local = local;
        tx->sdata = sdata;
        tx->channel = local->hw.conf.channel;
+       __skb_queue_head_init(&tx->skbs);
 
        /*
         * If this flag is set to true anywhere, and we get here,
@@ -1180,17 +1194,18 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
 /*
  * Returns false if the frame couldn't be transmitted but was queued instead.
  */
-static bool __ieee80211_tx(struct ieee80211_local *local, struct sk_buff **skbp,
+static bool __ieee80211_tx(struct ieee80211_local *local,
+                          struct sk_buff_head *skbs,
                           struct sta_info *sta, bool txpending)
 {
-       struct sk_buff *skb = *skbp, *next;
+       struct sk_buff *skb, *tmp;
        struct ieee80211_tx_info *info;
        struct ieee80211_sub_if_data *sdata;
        unsigned long flags;
        int len;
        bool fragm = false;
 
-       while (skb) {
+       skb_queue_walk_safe(skbs, skb, tmp) {
                int q = skb_get_queue_mapping(skb);
                __le16 fc;
 
@@ -1202,24 +1217,10 @@ static bool __ieee80211_tx(struct ieee80211_local *local, struct sk_buff **skbp,
                         * transmission from the tx-pending tasklet when the
                         * queue is woken again.
                         */
-
-                       do {
-                               next = skb->next;
-                               skb->next = NULL;
-                               /*
-                                * NB: If txpending is true, next must already
-                                * be NULL since we must've gone through this
-                                * loop before already; therefore we can just
-                                * queue the frame to the head without worrying
-                                * about reordering of fragments.
-                                */
-                               if (unlikely(txpending))
-                                       __skb_queue_head(&local->pending[q],
-                                                        skb);
-                               else
-                                       __skb_queue_tail(&local->pending[q],
-                                                        skb);
-                       } while ((skb = next));
+                       if (txpending)
+                               skb_queue_splice(skbs, &local->pending[q]);
+                       else
+                               skb_queue_splice_tail(skbs, &local->pending[q]);
 
                        spin_unlock_irqrestore(&local->queue_stop_reason_lock,
                                               flags);
@@ -1233,10 +1234,9 @@ static bool __ieee80211_tx(struct ieee80211_local *local, struct sk_buff **skbp,
                        info->flags &= ~(IEEE80211_TX_CTL_CLEAR_PS_FILT |
                                         IEEE80211_TX_CTL_FIRST_FRAGMENT);
 
-               next = skb->next;
                len = skb->len;
 
-               if (next)
+               if (!skb_queue_is_last(skbs, skb))
                        info->flags |= IEEE80211_TX_CTL_MORE_FRAMES;
 
                sdata = vif_to_sdata(info->control.vif);
@@ -1260,14 +1260,17 @@ static bool __ieee80211_tx(struct ieee80211_local *local, struct sk_buff **skbp,
                        info->control.sta = NULL;
 
                fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
+
+               __skb_unlink(skb, skbs);
                drv_tx(local, skb);
 
                ieee80211_tpt_led_trig_tx(local, fc, len);
-               *skbp = skb = next;
                ieee80211_led_tx(local, 1);
                fragm = true;
        }
 
+       WARN_ON(!skb_queue_empty(skbs));
+
        return true;
 }
 
@@ -1277,8 +1280,7 @@ static bool __ieee80211_tx(struct ieee80211_local *local, struct sk_buff **skbp,
  */
 static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
-       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
        ieee80211_tx_result res = TX_DROP;
 
 #define CALL_TXH(txh) \
@@ -1312,13 +1314,10 @@ static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
  txh_done:
        if (unlikely(res == TX_DROP)) {
                I802_DEBUG_INC(tx->local->tx_handlers_drop);
-               while (skb) {
-                       struct sk_buff *next;
-
-                       next = skb->next;
-                       dev_kfree_skb(skb);
-                       skb = next;
-               }
+               if (tx->skb)
+                       dev_kfree_skb(tx->skb);
+               else
+                       __skb_queue_purge(&tx->skbs);
                return -1;
        } else if (unlikely(res == TX_QUEUED)) {
                I802_DEBUG_INC(tx->local->tx_handlers_queued);
@@ -1361,7 +1360,7 @@ static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata,
        info->band = tx.channel->band;
 
        if (!invoke_tx_handlers(&tx))
-               result = __ieee80211_tx(local, &tx.skb, tx.sta, txpending);
+               result = __ieee80211_tx(local, &tx.skbs, tx.sta, txpending);
  out:
        rcu_read_unlock();
        return result;
@@ -2109,10 +2108,15 @@ static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
        if (info->flags & IEEE80211_TX_INTFL_NEED_TXPROCESSING) {
                result = ieee80211_tx(sdata, skb, true);
        } else {
+               struct sk_buff_head skbs;
+
+               __skb_queue_head_init(&skbs);
+               __skb_queue_tail(&skbs, skb);
+
                hdr = (struct ieee80211_hdr *)skb->data;
                sta = sta_info_get(sdata, hdr->addr1);
 
-               result = __ieee80211_tx(local, &skb, sta, true);
+               result = __ieee80211_tx(local, &skbs, sta, true);
        }
 
        return result;

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 4cf25b0..939bf24 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -95,13 +95,13 @@ u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
 
 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
+       struct sk_buff *skb;
        struct ieee80211_hdr *hdr;
 
-       do {
+       skb_queue_walk(&tx->skbs, skb) {
                hdr = (struct ieee80211_hdr *) skb->data;
                hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
-       } while ((skb = skb->next));
+       }
 }
 
 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,

diff --git a/net/mac80211/wep.c b/net/mac80211/wep.c
index a1c6bfd..68ad351 100644 (file)
--- a/net/mac80211/wep.c
+++ b/net/mac80211/wep.c
@@ -330,13 +330,12 @@ ieee80211_crypto_wep_encrypt(struct ieee80211_tx_data *tx)
 
        ieee80211_tx_set_protected(tx);
 
-       skb = tx->skb;
-       do {
+       skb_queue_walk(&tx->skbs, skb) {
                if (wep_encrypt_skb(tx, skb) < 0) {
                        I802_DEBUG_INC(tx->local->tx_handlers_drop_wep);
                        return TX_DROP;
                }
-       } while ((skb = skb->next));
+       }
 
        return TX_CONTINUE;
 }

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 106e15a..93aab07 100644 (file)
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -223,14 +223,14 @@ static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 ieee80211_tx_result
 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
+       struct sk_buff *skb;
 
        ieee80211_tx_set_protected(tx);
 
-       do {
+       skb_queue_walk(&tx->skbs, skb) {
                if (tkip_encrypt_skb(tx, skb) < 0)
                        return TX_DROP;
-       } while ((skb = skb->next));
+       }
 
        return TX_CONTINUE;
 }
@@ -449,14 +449,14 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 ieee80211_tx_result
 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
+       struct sk_buff *skb;
 
        ieee80211_tx_set_protected(tx);
 
-       do {
+       skb_queue_walk(&tx->skbs, skb) {
                if (ccmp_encrypt_skb(tx, skb) < 0)
                        return TX_DROP;
-       } while ((skb = skb->next));
+       }
 
        return TX_CONTINUE;
 }
@@ -554,15 +554,22 @@ static inline void bip_ipn_swap(u8 *d, const u8 *s)
 ieee80211_tx_result
 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 {
-       struct sk_buff *skb = tx->skb;
-       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+       struct sk_buff *skb;
+       struct ieee80211_tx_info *info;
        struct ieee80211_key *key = tx->key;
        struct ieee80211_mmie *mmie;
        u8 aad[20];
        u64 pn64;
 
+       if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
+               return TX_DROP;
+
+       skb = skb_peek(&tx->skbs);
+
+       info = IEEE80211_SKB_CB(skb);
+
        if (info->control.hw_key)
-               return 0;
+               return TX_CONTINUE;
 
        if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
                return TX_DROP;