package/kernel/mac80211/patches/subsys/307-mac80211-add-a-function-for-running-rx-without-passi.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sat, 25 Jul 2020 20:53:23 +0200
   3 Subject: [PATCH] mac80211: add a function for running rx without passing skbs
   4  to the stack
   5
   6 This can be used to run mac80211 rx processing on a batch of frames in NAPI
   7 poll before passing them to the network stack in a large batch.
   8 This can improve icache footprint, or it can be used to pass frames via
   9 netif_receive_skb_list.
  10
  11 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  12 ---
  13
  14 --- a/include/net/mac80211.h
  15 +++ b/include/net/mac80211.h
  16 @@ -4358,6 +4358,31 @@ void ieee80211_free_hw(struct ieee80211_
  17  void ieee80211_restart_hw(struct ieee80211_hw *hw);
  18
  19  /**
  20 + * ieee80211_rx_list - receive frame and store processed skbs in a list
  21 + *
  22 + * Use this function to hand received frames to mac80211. The receive
  23 + * buffer in @skb must start with an IEEE 802.11 header. In case of a
  24 + * paged @skb is used, the driver is recommended to put the ieee80211
  25 + * header of the frame on the linear part of the @skb to avoid memory
  26 + * allocation and/or memcpy by the stack.
  27 + *
  28 + * This function may not be called in IRQ context. Calls to this function
  29 + * for a single hardware must be synchronized against each other. Calls to
  30 + * this function, ieee80211_rx_ni() and ieee80211_rx_irqsafe() may not be
  31 + * mixed for a single hardware. Must not run concurrently with
  32 + * ieee80211_tx_status() or ieee80211_tx_status_ni().
  33 + *
  34 + * This function must be called with BHs disabled and RCU read lock
  35 + *
  36 + * @hw: the hardware this frame came in on
  37 + * @sta: the station the frame was received from, or %NULL
  38 + * @skb: the buffer to receive, owned by mac80211 after this call
  39 + * @list: the destination list
  40 + */
  41 +void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
  42 +                      struct sk_buff *skb, struct list_head *list);
  43 +
  44 +/**
  45   * ieee80211_rx_napi - receive frame from NAPI context
  46   *
  47   * Use this function to hand received frames to mac80211. The receive
  48 --- a/net/mac80211/ieee80211_i.h
  49 +++ b/net/mac80211/ieee80211_i.h
  50 @@ -218,7 +218,7 @@ enum ieee80211_rx_flags {
  51  };
  52
  53  struct ieee80211_rx_data {
  54 -       struct napi_struct *napi;
  55 +       struct list_head *list;
  56         struct sk_buff *skb;
  57         struct ieee80211_local *local;
  58         struct ieee80211_sub_if_data *sdata;
  59 --- a/net/mac80211/rx.c
  60 +++ b/net/mac80211/rx.c
  61 @@ -2552,8 +2552,8 @@ static void ieee80211_deliver_skb_to_loc
  62                 memset(skb->cb, 0, sizeof(skb->cb));
  63
  64                 /* deliver to local stack */
  65 -               if (rx->napi)
  66 -                       napi_gro_receive(rx->napi, skb);
  67 +               if (rx->list)
  68 +                       list_add_tail(&skb->list, rx->list);
  69                 else
  70                         netif_receive_skb(skb);
  71         }
  72 @@ -3843,7 +3843,6 @@ void ieee80211_release_reorder_timeout(s
  73                 /* This is OK -- must be QoS data frame */
  74                 .security_idx = tid,
  75                 .seqno_idx = tid,
  76 -               .napi = NULL, /* must be NULL to not have races */
  77         };
  78         struct tid_ampdu_rx *tid_agg_rx;
  79
  80 @@ -4453,8 +4452,8 @@ static bool ieee80211_invoke_fast_rx(str
  81         /* deliver to local stack */
  82         skb->protocol = eth_type_trans(skb, fast_rx->dev);
  83         memset(skb->cb, 0, sizeof(skb->cb));
  84 -       if (rx->napi)
  85 -               napi_gro_receive(rx->napi, skb);
  86 +       if (rx->list)
  87 +               list_add_tail(&skb->list, rx->list);
  88         else
  89                 netif_receive_skb(skb);
  90
  91 @@ -4521,7 +4520,7 @@ static bool ieee80211_prepare_and_rx_han
  92  static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
  93                                          struct ieee80211_sta *pubsta,
  94                                          struct sk_buff *skb,
  95 -                                        struct napi_struct *napi)
  96 +                                        struct list_head *list)
  97  {
  98         struct ieee80211_local *local = hw_to_local(hw);
  99         struct ieee80211_sub_if_data *sdata;
 100 @@ -4536,7 +4535,7 @@ static void __ieee80211_rx_handle_packet
 101         memset(&rx, 0, sizeof(rx));
 102         rx.skb = skb;
 103         rx.local = local;
 104 -       rx.napi = napi;
 105 +       rx.list = list;
 106
 107         if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
 108                 I802_DEBUG_INC(local->dot11ReceivedFragmentCount);
 109 @@ -4644,8 +4643,8 @@ static void __ieee80211_rx_handle_packet
 110   * This is the receive path handler. It is called by a low level driver when an
 111   * 802.11 MPDU is received from the hardware.
 112   */
 113 -void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
 114 -                      struct sk_buff *skb, struct napi_struct *napi)
 115 +void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
 116 +                      struct sk_buff *skb, struct list_head *list)
 117  {
 118         struct ieee80211_local *local = hw_to_local(hw);
 119         struct ieee80211_rate *rate = NULL;
 120 @@ -4737,36 +4736,53 @@ void ieee80211_rx_napi(struct ieee80211_
 121         status->rx_flags = 0;
 122
 123         /*
 124 -        * key references and virtual interfaces are protected using RCU
 125 -        * and this requires that we are in a read-side RCU section during
 126 -        * receive processing
 127 -        */
 128 -       rcu_read_lock();
 129 -
 130 -       /*
 131          * Frames with failed FCS/PLCP checksum are not returned,
 132          * all other frames are returned without radiotap header
 133          * if it was previously present.
 134          * Also, frames with less than 16 bytes are dropped.
 135          */
 136         skb = ieee80211_rx_monitor(local, skb, rate);
 137 -       if (!skb) {
 138 -               rcu_read_unlock();
 139 +       if (!skb)
 140                 return;
 141 -       }
 142
 143         ieee80211_tpt_led_trig_rx(local,
 144                         ((struct ieee80211_hdr *)skb->data)->frame_control,
 145                         skb->len);
 146
 147 -       __ieee80211_rx_handle_packet(hw, pubsta, skb, napi);
 148 -
 149 -       rcu_read_unlock();
 150 +       __ieee80211_rx_handle_packet(hw, pubsta, skb, list);
 151
 152         return;
 153   drop:
 154         kfree_skb(skb);
 155  }
 156 +EXPORT_SYMBOL(ieee80211_rx_list);
 157 +
 158 +void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
 159 +                      struct sk_buff *skb, struct napi_struct *napi)
 160 +{
 161 +       struct sk_buff *tmp;
 162 +       LIST_HEAD(list);
 163 +
 164 +
 165 +       /*
 166 +        * key references and virtual interfaces are protected using RCU
 167 +        * and this requires that we are in a read-side RCU section during
 168 +        * receive processing
 169 +        */
 170 +       rcu_read_lock();
 171 +       ieee80211_rx_list(hw, pubsta, skb, &list);
 172 +       rcu_read_unlock();
 173 +
 174 +       if (!napi) {
 175 +               netif_receive_skb_list(&list);
 176 +               return;
 177 +       }
 178 +
 179 +       list_for_each_entry_safe(skb, tmp, &list, list) {
 180 +               skb_list_del_init(skb);
 181 +               napi_gro_receive(napi, skb);
 182 +       }
 183 +}
 184  EXPORT_SYMBOL(ieee80211_rx_napi);
 185
 186  /* This is a version of the rx handler that can be called from hard irq