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mac80211: cleanup reorder buffer handling

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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 <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2009-11-16 12:00:40 +01:00 committed by John W. Linville
parent af2ced6a32
commit a02ae758e8
1 changed files with 81 additions and 81 deletions
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162
net/mac80211/rx.c
View File

@ -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);
}
/*