From a02ae758e8780d737b6d0135d6292bb3043e7eea Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 16 Nov 2009 12:00:40 +0100 Subject: [PATCH] mac80211: cleanup reorder buffer handling The reorder buffer handling is written in a quite peculiar style (especially comments) and also has a quirk where it invokes the entire reorder code in ieee80211_sta_manage_reorder_buf() for just a handful of lines in it with a special argument. Split out ieee80211_release_reorder_frames which can then be invoked from BAR handling and other reordering code, clean up code and comments and remove function arguments that are now unused from ieee80211_sta_manage_reorder_buf(). Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/rx.c | 162 +++++++++++++++++++++++----------------------- 1 file changed, 81 insertions(+), 81 deletions(-) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 68d9e9c86595..37e9891605b4 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -27,11 +27,10 @@ #include "tkip.h" #include "wme.h" -static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, - struct tid_ampdu_rx *tid_agg_rx, - struct sk_buff *skb, - u16 mpdu_seq_num, - int bar_req); +static void ieee80211_release_reorder_frames(struct ieee80211_hw *hw, + struct tid_ampdu_rx *tid_agg_rx, + u16 head_seq_num); + /* * monitor mode reception * @@ -1592,11 +1591,11 @@ ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx) if (ieee80211_is_back_req(bar->frame_control)) { if (!rx->sta) - return RX_CONTINUE; + return RX_DROP_MONITOR; tid = le16_to_cpu(bar->control) >> 12; if (rx->sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_OPERATIONAL) - return RX_CONTINUE; + return RX_DROP_MONITOR; tid_agg_rx = rx->sta->ampdu_mlme.tid_rx[tid]; start_seq_num = le16_to_cpu(bar->start_seq_num) >> 4; @@ -1606,13 +1605,10 @@ ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx) mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(tid_agg_rx->timeout)); - /* manage reordering buffer according to requested */ - /* sequence number */ - rcu_read_lock(); - ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, NULL, - start_seq_num, 1); - rcu_read_unlock(); - return RX_DROP_UNUSABLE; + /* release stored frames up to start of BAR */ + ieee80211_release_reorder_frames(hw, tid_agg_rx, start_seq_num); + kfree_skb(skb); + return RX_QUEUED; } return RX_CONTINUE; @@ -2223,6 +2219,18 @@ no_frame: tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num); } +static void ieee80211_release_reorder_frames(struct ieee80211_hw *hw, + struct tid_ampdu_rx *tid_agg_rx, + u16 head_seq_num) +{ + int index; + + while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) { + index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) % + tid_agg_rx->buf_size; + ieee80211_release_reorder_frame(hw, tid_agg_rx, index); + } +} /* * Timeout (in jiffies) for skb's that are waiting in the RX reorder buffer. If @@ -2234,15 +2242,17 @@ no_frame: #define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10) /* - * As it function blongs to Rx path it must be called with - * the proper rcu_read_lock protection for its flow. + * As this function belongs to the RX path it must be under + * rcu_read_lock protection. It returns false if the frame + * can be processed immediately, true if it was consumed. */ -static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, - struct tid_ampdu_rx *tid_agg_rx, - struct sk_buff *skb, - u16 mpdu_seq_num, - int bar_req) +static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, + struct tid_ampdu_rx *tid_agg_rx, + struct sk_buff *skb) { + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + u16 sc = le16_to_cpu(hdr->seq_ctrl); + u16 mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4; u16 head_seq_num, buf_size; int index; @@ -2252,47 +2262,37 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, /* frame with out of date sequence number */ if (seq_less(mpdu_seq_num, head_seq_num)) { dev_kfree_skb(skb); - return 1; + return true; } - /* if frame sequence number exceeds our buffering window size or - * block Ack Request arrived - release stored frames */ - if ((!seq_less(mpdu_seq_num, head_seq_num + buf_size)) || (bar_req)) { - /* new head to the ordering buffer */ - if (bar_req) - head_seq_num = mpdu_seq_num; - else - head_seq_num = - seq_inc(seq_sub(mpdu_seq_num, buf_size)); + /* + * If frame the sequence number exceeds our buffering window + * size release some previous frames to make room for this one. + */ + if (!seq_less(mpdu_seq_num, head_seq_num + buf_size)) { + head_seq_num = seq_inc(seq_sub(mpdu_seq_num, buf_size)); /* release stored frames up to new head to stack */ - while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) { - index = seq_sub(tid_agg_rx->head_seq_num, - tid_agg_rx->ssn) - % tid_agg_rx->buf_size; - ieee80211_release_reorder_frame(hw, tid_agg_rx, - index); - } - if (bar_req) - return 1; + ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num); } - /* now the new frame is always in the range of the reordering */ - /* buffer window */ - index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) - % tid_agg_rx->buf_size; + /* Now the new frame is always in the range of the reordering buffer */ + + index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) % tid_agg_rx->buf_size; + /* check if we already stored this frame */ if (tid_agg_rx->reorder_buf[index]) { dev_kfree_skb(skb); - return 1; + return true; } - /* if arrived mpdu is in the right order and nothing else stored */ - /* release it immediately */ + /* + * If the current MPDU is in the right order and nothing else + * is stored we can process it directly, no need to buffer it. + */ if (mpdu_seq_num == tid_agg_rx->head_seq_num && - tid_agg_rx->stored_mpdu_num == 0) { - tid_agg_rx->head_seq_num = - seq_inc(tid_agg_rx->head_seq_num); - return 0; + tid_agg_rx->stored_mpdu_num == 0) { + tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num); + return false; } /* put the frame in the reordering buffer */ @@ -2300,8 +2300,8 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, tid_agg_rx->reorder_time[index] = jiffies; tid_agg_rx->stored_mpdu_num++; /* release the buffer until next missing frame */ - index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) - % tid_agg_rx->buf_size; + index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) % + tid_agg_rx->buf_size; if (!tid_agg_rx->reorder_buf[index] && tid_agg_rx->stored_mpdu_num > 1) { /* @@ -2312,12 +2312,12 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, int skipped = 1; for (j = (index + 1) % tid_agg_rx->buf_size; j != index; j = (j + 1) % tid_agg_rx->buf_size) { - if (tid_agg_rx->reorder_buf[j] == NULL) { + if (!tid_agg_rx->reorder_buf[j]) { skipped++; continue; } if (!time_after(jiffies, tid_agg_rx->reorder_time[j] + - HZ / 10)) + HT_RX_REORDER_BUF_TIMEOUT)) break; #ifdef CONFIG_MAC80211_HT_DEBUG @@ -2333,51 +2333,56 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, * Increment the head seq# also for the skipped slots. */ tid_agg_rx->head_seq_num = - (tid_agg_rx->head_seq_num + skipped) & - SEQ_MASK; + (tid_agg_rx->head_seq_num + skipped) & SEQ_MASK; skipped = 0; } } else while (tid_agg_rx->reorder_buf[index]) { ieee80211_release_reorder_frame(hw, tid_agg_rx, index); - index = seq_sub(tid_agg_rx->head_seq_num, - tid_agg_rx->ssn) % tid_agg_rx->buf_size; + index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) % + tid_agg_rx->buf_size; } - return 1; + + return true; } -static u8 ieee80211_rx_reorder_ampdu(struct ieee80211_local *local, - struct sk_buff *skb) +/* + * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns + * true if the MPDU was buffered, false if it should be processed. + */ +static bool ieee80211_rx_reorder_ampdu(struct ieee80211_local *local, + struct sk_buff *skb) { struct ieee80211_hw *hw = &local->hw; struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct sta_info *sta; struct tid_ampdu_rx *tid_agg_rx; u16 sc; - u16 mpdu_seq_num; - u8 ret = 0; int tid; + if (!ieee80211_is_data_qos(hdr->frame_control)) + return false; + + /* + * filter the QoS data rx stream according to + * STA/TID and check if this STA/TID is on aggregation + */ + sta = sta_info_get(local, hdr->addr2); if (!sta) - return ret; - - /* filter the QoS data rx stream according to - * STA/TID and check if this STA/TID is on aggregation */ - if (!ieee80211_is_data_qos(hdr->frame_control)) - goto end_reorder; + return false; tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_OPERATIONAL) - goto end_reorder; + return false; tid_agg_rx = sta->ampdu_mlme.tid_rx[tid]; /* qos null data frames are excluded */ if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC))) - goto end_reorder; + return false; - /* new un-ordered ampdu frame - process it */ + /* new, potentially un-ordered, ampdu frame - process it */ /* reset session timer */ if (tid_agg_rx->timeout) @@ -2389,16 +2394,11 @@ static u8 ieee80211_rx_reorder_ampdu(struct ieee80211_local *local, if (sc & IEEE80211_SCTL_FRAG) { ieee80211_sta_stop_rx_ba_session(sta->sdata, sta->sta.addr, tid, 0, WLAN_REASON_QSTA_REQUIRE_SETUP); - ret = 1; - goto end_reorder; + dev_kfree_skb(skb); + return true; } - /* according to mpdu sequence number deal with reordering buffer */ - mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4; - ret = ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, - mpdu_seq_num, 0); - end_reorder: - return ret; + return ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb); } /* -- 2.20.1