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mac80211: fix an issue with the TXQ scheduling API and powersave clients

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This commit is contained in:
coolsnowwolf 2019-03-21 14:09:06 +08:00
parent 6c1c7e4a1e
commit f0dd52f007
3 changed files with 334 additions and 0 deletions
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198
package/kernel/mac80211/patches/subsys/357-mac80211-optimize-skb-resizing.patch Normal file
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@ -0,0 +1,198 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 17 Mar 2019 18:11:30 +0100
Subject: [PATCH] mac80211: optimize skb resizing
When forwarding unicast packets from ethernet to batman-adv over 802.11s
(with forwarding disabled), the typical required headroom to transmit
encrypted packets on mt76 is 32 (802.11) + 6 (802.11s) + 8 (CCMP) +
2 (padding) + 6 (LLC) + 18 (batman-adv) - 14 (old ethernet header) = 58 bytes.
On systems where NET_SKB_PAD is 64 this leads to a call to pskb_expand_head
for every packet, since mac80211 also tries to allocate 16 bytes status
headroom for radiotap headers.
This patch fixes these unnecessary reallocations by only requiring the extra
status headroom in ieee80211_tx_monitor()
If however a reallocation happens before that call, the status headroom gets
added there as well, in order to avoid double reallocation.
The patch also cleans up the code by moving the headroom calculation to
ieee80211_skb_resize.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1761,6 +1761,8 @@ void ieee80211_clear_fast_xmit(struct st
int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
const u8 *buf, size_t len,
const u8 *dest, __be16 proto, bool unencrypted);
+int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata,
+ struct sk_buff *skb, int hdrlen, int hdr_add);
/* HT */
void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -672,6 +672,11 @@ void ieee80211_tx_monitor(struct ieee802
}
}
+ if (ieee80211_skb_resize(NULL, skb, 0, 0)) {
+ dev_kfree_skb(skb);
+ return;
+ }
+
/* send frame to monitor interfaces now */
rtap_len = ieee80211_tx_radiotap_len(info);
if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1914,37 +1914,53 @@ static bool ieee80211_tx(struct ieee8021
}
/* device xmit handlers */
-
-static int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata,
- struct sk_buff *skb,
- int head_need, bool may_encrypt)
+int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata,
+ struct sk_buff *skb, int hdr_len, int hdr_extra)
{
struct ieee80211_local *local = sdata->local;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr;
- bool enc_tailroom;
- int tail_need = 0;
+ int head_need, head_max;
+ int tail_need, tail_max;
+ bool enc_tailroom = false;
- hdr = (struct ieee80211_hdr *) skb->data;
- enc_tailroom = may_encrypt &&
- (sdata->crypto_tx_tailroom_needed_cnt ||
- ieee80211_is_mgmt(hdr->frame_control));
+ if (sdata && !hdr_len &&
+ !(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT)) {
+ hdr = (struct ieee80211_hdr *) skb->data;
+ enc_tailroom = (sdata->crypto_tx_tailroom_needed_cnt ||
+ ieee80211_is_mgmt(hdr->frame_control));
+ hdr_len += sdata->encrypt_headroom;
+ }
- if (enc_tailroom) {
- tail_need = IEEE80211_ENCRYPT_TAILROOM;
- tail_need -= skb_tailroom(skb);
- tail_need = max_t(int, tail_need, 0);
+ head_need = head_max = hdr_len;
+ tail_need = tail_max = 0;
+ if (!sdata) {
+ head_need = head_max = local->tx_headroom;
+ } else {
+ head_max += hdr_extra;
+ head_max += max_t(int, local->tx_headroom,
+ local->hw.extra_tx_headroom);
+ head_need += local->hw.extra_tx_headroom;
+
+ tail_max = IEEE80211_ENCRYPT_TAILROOM;
+ if (enc_tailroom)
+ tail_need = tail_max;
}
if (skb_cloned(skb) &&
(!ieee80211_hw_check(&local->hw, SUPPORTS_CLONED_SKBS) ||
!skb_clone_writable(skb, ETH_HLEN) || enc_tailroom))
I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
- else if (head_need || tail_need)
+ else if (head_need > skb_headroom(skb) ||
+ tail_need > skb_tailroom(skb))
I802_DEBUG_INC(local->tx_expand_skb_head);
else
return 0;
- if (pskb_expand_head(skb, head_need, tail_need, GFP_ATOMIC)) {
+ head_max = max_t(int, 0, head_max - skb_headroom(skb));
+ tail_max = max_t(int, 0, tail_max - skb_tailroom(skb));
+
+ if (pskb_expand_head(skb, head_max, tail_max, GFP_ATOMIC)) {
wiphy_debug(local->hw.wiphy,
"failed to reallocate TX buffer\n");
return -ENOMEM;
@@ -1960,18 +1976,8 @@ void ieee80211_xmit(struct ieee80211_sub
struct ieee80211_local *local = sdata->local;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr;
- int headroom;
- bool may_encrypt;
-
- may_encrypt = !(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT);
-
- headroom = local->tx_headroom;
- if (may_encrypt)
- headroom += sdata->encrypt_headroom;
- headroom -= skb_headroom(skb);
- headroom = max_t(int, 0, headroom);
- if (ieee80211_skb_resize(sdata, skb, headroom, may_encrypt)) {
+ if (ieee80211_skb_resize(sdata, skb, 0, 0)) {
ieee80211_free_txskb(&local->hw, skb);
return;
}
@@ -2740,30 +2746,14 @@ static struct sk_buff *ieee80211_build_h
skb_pull(skb, skip_header_bytes);
padsize = ieee80211_hdr_padsize(&local->hw, hdrlen);
- head_need = hdrlen + encaps_len + meshhdrlen - skb_headroom(skb);
+ head_need = hdrlen + encaps_len + meshhdrlen;
head_need += padsize;
- /*
- * So we need to modify the skb header and hence need a copy of
- * that. The head_need variable above doesn't, so far, include
- * the needed header space that we don't need right away. If we
- * can, then we don't reallocate right now but only after the
- * frame arrives at the master device (if it does...)
- *
- * If we cannot, however, then we will reallocate to include all
- * the ever needed space. Also, if we need to reallocate it anyway,
- * make it big enough for everything we may ever need.
- */
-
- if (head_need > 0 || skb_cloned(skb)) {
- head_need += sdata->encrypt_headroom;
- head_need += local->tx_headroom;
- head_need = max_t(int, 0, head_need);
- if (ieee80211_skb_resize(sdata, skb, head_need, true)) {
- ieee80211_free_txskb(&local->hw, skb);
- skb = NULL;
- return ERR_PTR(-ENOMEM);
- }
+ if (ieee80211_skb_resize(sdata, skb, head_need,
+ sdata->encrypt_headroom)) {
+ ieee80211_free_txskb(&local->hw, skb);
+ skb = NULL;
+ return ERR_PTR(-ENOMEM);
}
if (encaps_data)
@@ -3377,7 +3367,6 @@ static bool ieee80211_xmit_fast(struct i
struct ieee80211_local *local = sdata->local;
u16 ethertype = (skb->data[12] << 8) | skb->data[13];
int extra_head = fast_tx->hdr_len - (ETH_HLEN - 2);
- int hw_headroom = sdata->local->hw.extra_tx_headroom;
struct ethhdr eth;
struct ieee80211_tx_info *info;
struct ieee80211_hdr *hdr = (void *)fast_tx->hdr;
@@ -3429,10 +3418,7 @@ static bool ieee80211_xmit_fast(struct i
* as the may-encrypt argument for the resize to not account for
* more room than we already have in 'extra_head'
*/
- if (unlikely(ieee80211_skb_resize(sdata, skb,
- max_t(int, extra_head + hw_headroom -
- skb_headroom(skb), 0),
- false))) {
+ if (unlikely(ieee80211_skb_resize(sdata, skb, extra_head, 0))) {
kfree_skb(skb);
return true;
}

105
package/kernel/mac80211/patches/subsys/358-mac80211-make-ieee80211_schedule_txq-schedule-empty-.patch Normal file
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From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 17 Mar 2019 14:26:59 +0100
Subject: [PATCH] mac80211: make ieee80211_schedule_txq schedule empty TXQs
Currently there is no way for the driver to signal to mac80211 that it should
schedule a TXQ even if there are no packets on the mac80211 part of that queue.
This is problematic if the driver has an internal retry queue to deal with
software A-MPDU retry.
This patch changes the behavior of ieee80211_schedule_txq to always schedule
the queue, as its only user (ath9k) seems to expect such behavior already:
it calls this function on tx status and on powersave wakeup whenever its
internal retry queue is not empty.
Also add an extra argument to ieee80211_return_txq to get the same behavior.
This fixes an issue on ath9k where tx queues with packets to retry (and no
new packets in mac80211) would not get serviced.
Fixes: 89cea7493a346 ("ath9k: Switch to mac80211 TXQ scheduling and airtime APIs")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -6090,26 +6090,42 @@ static inline void ieee80211_txq_schedul
{
}
+void __ieee80211_schedule_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq, bool force);
+
/**
* ieee80211_schedule_txq - schedule a TXQ for transmission
*
* @hw: pointer as obtained from ieee80211_alloc_hw()
* @txq: pointer obtained from station or virtual interface
*
- * Schedules a TXQ for transmission if it is not already scheduled.
+ * Schedules a TXQ for transmission if it is not already scheduled,
+ * even if mac80211 does not have any packets buffered.
+ *
+ * The driver may call this function if it has buffered packets for
+ * this TXQ internally.
*/
-void ieee80211_schedule_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq);
+static inline void
+ieee80211_schedule_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
+{
+ __ieee80211_schedule_txq(hw, txq, true);
+}
/**
* ieee80211_return_txq - return a TXQ previously acquired by ieee80211_next_txq()
*
* @hw: pointer as obtained from ieee80211_alloc_hw()
* @txq: pointer obtained from station or virtual interface
+ * @force: schedule txq even if mac80211 does not have any buffered packets.
+ *
+ * The driver may set force=true if it has buffered packets for this TXQ
+ * internally.
*/
static inline void
-ieee80211_return_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
+ieee80211_return_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq,
+ bool force)
{
- ieee80211_schedule_txq(hw, txq);
+ __ieee80211_schedule_txq(hw, txq, force);
}
/**
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3655,8 +3655,9 @@ out:
}
EXPORT_SYMBOL(ieee80211_next_txq);
-void ieee80211_schedule_txq(struct ieee80211_hw *hw,
- struct ieee80211_txq *txq)
+void __ieee80211_schedule_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq,
+ bool force)
{
struct ieee80211_local *local = hw_to_local(hw);
struct txq_info *txqi = to_txq_info(txq);
@@ -3664,7 +3665,8 @@ void ieee80211_schedule_txq(struct ieee8
spin_lock_bh(&local->active_txq_lock[txq->ac]);
if (list_empty(&txqi->schedule_order) &&
- (!skb_queue_empty(&txqi->frags) || txqi->tin.backlog_packets)) {
+ (force || !skb_queue_empty(&txqi->frags) ||
+ txqi->tin.backlog_packets)) {
/* If airtime accounting is active, always enqueue STAs at the
* head of the list to ensure that they only get moved to the
* back by the airtime DRR scheduler once they have a negative
@@ -3684,7 +3686,7 @@ void ieee80211_schedule_txq(struct ieee8
spin_unlock_bh(&local->active_txq_lock[txq->ac]);
}
-EXPORT_SYMBOL(ieee80211_schedule_txq);
+EXPORT_SYMBOL(__ieee80211_schedule_txq);
bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw,
struct ieee80211_txq *txq)

31
package/kernel/mac80211/patches/subsys/359-mac80211-un-schedule-TXQs-on-powersave-start.patch Normal file
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@ -0,0 +1,31 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Tue, 19 Mar 2019 11:36:12 +0100
Subject: [PATCH] mac80211: un-schedule TXQs on powersave start
Once a station enters powersave, its queues should not be returned by
ieee80211_next_txq() anymore. They will be re-scheduled again after the
station has woken up again
Fixes: 1866760096bf4 ("mac80211: Add TXQ scheduling API")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1508,7 +1508,15 @@ static void sta_ps_start(struct sta_info
return;
for (tid = 0; tid < ARRAY_SIZE(sta->sta.txq); tid++) {
- if (txq_has_queue(sta->sta.txq[tid]))
+ struct ieee80211_txq *txq = sta->sta.txq[tid];
+ struct txq_info *txqi = to_txq_info(txq);
+
+ spin_lock(&local->active_txq_lock[txq->ac]);
+ if (!list_empty(&txqi->schedule_order))
+ list_del_init(&txqi->schedule_order);
+ spin_unlock(&local->active_txq_lock[txq->ac]);
+
+ if (txq_has_queue(txq))
set_bit(tid, &sta->txq_buffered_tids);
else
clear_bit(tid, &sta->txq_buffered_tids);