Return-path: Received: from nbd.name ([46.4.11.11]:46804 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756334AbcBXVYR (ORCPT ); Wed, 24 Feb 2016 16:24:17 -0500 From: Felix Fietkau To: linux-wireless@vger.kernel.org Cc: johannes@sipsolutions.net, egrumbach@gmail.com Subject: [PATCH v2 1/2] mac80211: add A-MSDU tx support Date: Wed, 24 Feb 2016 10:28:59 +0100 Message-Id: <1456306140-78485-1-git-send-email-nbd@openwrt.org> (sfid-20160224_222420_630856_09CB1513) Sender: linux-wireless-owner@vger.kernel.org List-ID: Requires software tx queueing and fast-xmit support. For good performance, drivers need frag_list support as well. This avoids the need for copying data of aggregated frames. Running without it is only supported for debugging purposes. To avoid performance and packet size issues, the rate control module or driver needs to limit the maximum A-MSDU size by setting max_rc_amsdu_len in struct ieee80211_sta. Signed-off-by: Felix Fietkau --- include/net/mac80211.h | 19 ++++++ net/mac80211/agg-tx.c | 5 ++ net/mac80211/debugfs.c | 2 + net/mac80211/ieee80211_i.h | 1 + net/mac80211/tx.c | 165 +++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 192 insertions(+) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 0c09da3..da03bb9 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -709,6 +709,7 @@ enum mac80211_tx_info_flags { * @IEEE80211_TX_CTRL_PS_RESPONSE: This frame is a response to a poll * frame (PS-Poll or uAPSD). * @IEEE80211_TX_CTRL_RATE_INJECT: This frame is injected with rate information + * @IEEE80211_TX_CTRL_AMSDU: This frame is an A-MSDU frame * * These flags are used in tx_info->control.flags. */ @@ -716,6 +717,7 @@ enum mac80211_tx_control_flags { IEEE80211_TX_CTRL_PORT_CTRL_PROTO = BIT(0), IEEE80211_TX_CTRL_PS_RESPONSE = BIT(1), IEEE80211_TX_CTRL_RATE_INJECT = BIT(2), + IEEE80211_TX_CTRL_AMSDU = BIT(3), }; /* @@ -1735,6 +1737,7 @@ struct ieee80211_sta_rates { * size is min(max_amsdu_len, 7935) bytes. * Both additional HT limits must be enforced by the low level driver. * This is defined by the spec (IEEE 802.11-2012 section 8.3.2.2 NOTE 2). + * @max_rc_amsdu_len: Maximum A-MSDU size in bytes recommended by rate control. * @txq: per-TID data TX queues (if driver uses the TXQ abstraction) */ struct ieee80211_sta { @@ -1755,6 +1758,7 @@ struct ieee80211_sta { bool mfp; u8 max_amsdu_subframes; u16 max_amsdu_len; + u16 max_rc_amsdu_len; struct ieee80211_txq *txq[IEEE80211_NUM_TIDS]; @@ -1968,6 +1972,15 @@ struct ieee80211_txq { * order and does not need to manage its own reorder buffer or BA session * timeout. * + * @IEEE80211_HW_TX_AMSDU: Hardware (or driver) supports software aggregated + * A-MSDU frames. Requires software tx queueing and fast-xmit support. + * When not using minstrel/minstrel_ht rate control, the driver should + * limit the maximum A-MSDU size based on the current tx rate by setting + * max_rc_amsdu_len in struct ieee80211_sta. + * + * @IEEE80211_HW_TX_FRAG_LIST: Hardware (or driver) supports sending frag_list + * skbs, needed for zero-copy software A-MSDU. + * * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays */ enum ieee80211_hw_flags { @@ -2005,6 +2018,8 @@ enum ieee80211_hw_flags { IEEE80211_HW_BEACON_TX_STATUS, IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR, IEEE80211_HW_SUPPORTS_REORDERING_BUFFER, + IEEE80211_HW_TX_AMSDU, + IEEE80211_HW_TX_FRAG_LIST, /* keep last, obviously */ NUM_IEEE80211_HW_FLAGS @@ -2077,6 +2092,9 @@ enum ieee80211_hw_flags { * size is smaller (an example is LinkSys WRT120N with FW v1.0.07 * build 002 Jun 18 2012). * + * @max_tx_fragments: maximum number of tx buffers per (A)-MSDU, sum + * of 1 + skb_shinfo(skb)->nr_frags for each skb in the frag_list. + * * @offchannel_tx_hw_queue: HW queue ID to use for offchannel TX * (if %IEEE80211_HW_QUEUE_CONTROL is set) * @@ -2131,6 +2149,7 @@ struct ieee80211_hw { u8 max_rate_tries; u8 max_rx_aggregation_subframes; u8 max_tx_aggregation_subframes; + u8 max_tx_fragments; u8 offchannel_tx_hw_queue; u8 radiotap_mcs_details; u16 radiotap_vht_details; diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index 4932e9f..42fa810 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -935,6 +935,7 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local, size_t len) { struct tid_ampdu_tx *tid_tx; + struct ieee80211_txq *txq; u16 capab, tid; u8 buf_size; bool amsdu; @@ -945,6 +946,10 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local, buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6; buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes); + txq = sta->sta.txq[tid]; + if (!amsdu && txq) + set_bit(IEEE80211_TXQ_NO_AMSDU, &to_txq_info(txq)->flags); + mutex_lock(&sta->ampdu_mlme.mtx); tid_tx = rcu_dereference_protected_tid_tx(sta, tid); diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c index e433d0c..847779d 100644 --- a/net/mac80211/debugfs.c +++ b/net/mac80211/debugfs.c @@ -127,6 +127,8 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = { FLAG(BEACON_TX_STATUS), FLAG(NEEDS_UNIQUE_STA_ADDR), FLAG(SUPPORTS_REORDERING_BUFFER), + FLAG(TX_AMSDU), + FLAG(TX_FRAG_LIST), /* keep last for the build bug below */ (void *)0x1 diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 1630975..554ad0b 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -797,6 +797,7 @@ struct mac80211_qos_map { enum txq_info_flags { IEEE80211_TXQ_STOP, IEEE80211_TXQ_AMPDU, + IEEE80211_TXQ_NO_AMSDU, }; struct txq_info { diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 3a7475f..5def9d0 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1324,6 +1324,10 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, out: spin_unlock_bh(&txqi->queue.lock); + if (skb && skb_has_frag_list(skb) && + !ieee80211_hw_check(&local->hw, TX_FRAG_LIST)) + skb_linearize(skb); + return skb; } EXPORT_SYMBOL(ieee80211_tx_dequeue); @@ -2767,6 +2771,163 @@ void ieee80211_clear_fast_xmit(struct sta_info *sta) kfree_rcu(fast_tx, rcu_head); } +static bool ieee80211_amsdu_realloc_pad(struct ieee80211_local *local, + struct sk_buff *skb, int headroom, + int *subframe_len) +{ + int amsdu_len = *subframe_len + sizeof(struct ethhdr); + int padding = (4 - amsdu_len) & 3; + + if (skb_headroom(skb) < headroom || skb_tailroom(skb) < padding) { + I802_DEBUG_INC(local->tx_expand_skb_head); + + if (pskb_expand_head(skb, headroom, padding, GFP_ATOMIC)) { + wiphy_debug(local->hw.wiphy, + "failed to reallocate TX buffer\n"); + return false; + } + } + + if (padding) { + *subframe_len += padding; + memset(skb_put(skb, padding), 0, padding); + } + + return true; +} + +static bool ieee80211_amsdu_prepare_head(struct ieee80211_sub_if_data *sdata, + struct ieee80211_fast_tx *fast_tx, + struct sk_buff *skb) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); + struct ieee80211_hdr *hdr; + struct ethhdr amsdu_hdr; + int hdr_len = fast_tx->hdr_len - sizeof(rfc1042_header); + int subframe_len = skb->len - hdr_len; + void *data; + u8 *qc; + + if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) + return false; + + if (info->control.flags & IEEE80211_TX_CTRL_AMSDU) + return true; + + if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(amsdu_hdr), + &subframe_len)) + return false; + + amsdu_hdr.h_proto = cpu_to_be16(subframe_len); + memcpy(amsdu_hdr.h_source, skb->data + fast_tx->sa_offs, ETH_ALEN); + memcpy(amsdu_hdr.h_dest, skb->data + fast_tx->da_offs, ETH_ALEN); + + data = skb_push(skb, sizeof(amsdu_hdr)); + memmove(data, data + sizeof(amsdu_hdr), hdr_len); + memcpy(data + hdr_len, &amsdu_hdr, sizeof(amsdu_hdr)); + + hdr = data; + qc = ieee80211_get_qos_ctl(hdr); + *qc |= IEEE80211_QOS_CTL_A_MSDU_PRESENT; + + info->control.flags |= IEEE80211_TX_CTRL_AMSDU; + + return true; +} + +static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata, + struct sta_info *sta, + struct ieee80211_fast_tx *fast_tx, + struct sk_buff *skb) +{ + struct ieee80211_local *local = sdata->local; + u8 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK; + struct ieee80211_txq *txq = sta->sta.txq[tid]; + struct txq_info *txqi; + struct sk_buff **frag_tail, *head; + int subframe_len = skb->len - ETH_ALEN; + u8 max_subframes = sta->sta.max_amsdu_subframes; + int max_frags = local->hw.max_tx_fragments; + int max_amsdu_len = sta->sta.max_amsdu_len; + __be16 len; + void *data; + bool ret = false; + int n = 1, nfrags; + + if (!ieee80211_hw_check(&local->hw, TX_AMSDU)) + return false; + + if (!txq) + return false; + + txqi = to_txq_info(txq); + if (test_bit(IEEE80211_TXQ_NO_AMSDU, &txqi->flags)) + return false; + + if (sta->sta.max_rc_amsdu_len) + max_amsdu_len = min_t(int, max_amsdu_len, + sta->sta.max_rc_amsdu_len); + + spin_lock_bh(&txqi->queue.lock); + + head = skb_peek_tail(&txqi->queue); + if (!head) + goto out; + + if (skb->len + head->len > max_amsdu_len) + goto out; + + /* + * HT A-MPDU limits maximum MPDU size to 4095 bytes. Since aggregation + * sessions are started/stopped without txq flush, use the limit here + * to avoid having to de-aggregate later. + */ + if (skb->len + head->len > 4095 && + !sta->sta.vht_cap.vht_supported) + goto out; + + if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head)) + goto out; + + nfrags = 1 + skb_shinfo(skb)->nr_frags; + nfrags += 1 + skb_shinfo(head)->nr_frags; + frag_tail = &skb_shinfo(head)->frag_list; + while (*frag_tail) { + nfrags += 1 + skb_shinfo(*frag_tail)->nr_frags; + frag_tail = &(*frag_tail)->next; + n++; + } + + if (max_subframes && n > max_subframes) + goto out; + + if (max_frags && nfrags > max_frags) + goto out; + + if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(rfc1042_header) + 2, + &subframe_len)) + return false; + + ret = true; + data = skb_push(skb, ETH_ALEN + 2); + memmove(data, data + ETH_ALEN + 2, 2 * ETH_ALEN); + + data += 2 * ETH_ALEN; + len = cpu_to_be16(subframe_len); + memcpy(data, &len, 2); + memcpy(data + 2, rfc1042_header, sizeof(rfc1042_header)); + + head->len += skb->len; + head->data_len += skb->len; + *frag_tail = skb; + +out: + spin_unlock_bh(&txqi->queue.lock); + + return ret; +} + static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata, struct net_device *dev, struct sta_info *sta, struct ieee80211_fast_tx *fast_tx, @@ -2821,6 +2982,10 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata, ieee80211_tx_stats(dev, skb->len + extra_head); + if ((hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) && + ieee80211_amsdu_aggregate(sdata, sta, fast_tx, skb)) + return true; + /* will not be crypto-handled beyond what we do here, so use false * as the may-encrypt argument for the resize to not account for * more room than we already have in 'extra_head' -- 2.2.2