ath9k: avoid the copy skb->cb on every RX'd skb

The skb->cb (control buffer, 48 bytes) is available to the skb
upon skb allocation. You can fill it up imediately after skb
allocation. ath9k was copying onto the skb->cb the data from the
processed skb for mac80211 from a stack struct ieee80211_rx_status
structure. This is unnecessary, instead use the skb->cb for the
rx status immediately after the skb becomes available and DMA
synched.

Additionally, avoid the copy of the skb->cb also for virtual wiphys
as skb_copy() will copy over the skb->cb for us as well.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 4c4c22f54e99b26da9a5e2616ec71ca284901a92..079361423efcfb3389724d04115e43e2fbedcb55 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -283,8 +283,6 @@ static int ath_rx_prepare(struct ath_common *common,
 {
        struct ath_hw *ah = common->ah;
 
-       memset(rx_status, 0, sizeof(struct ieee80211_rx_status));
-
        if (!ath9k_rx_accept(common, skb, rx_status, rx_stats, decrypt_error))
                goto rx_next;
 
@@ -654,7 +652,7 @@ static void ath_rx_ps(struct ath_softc *sc, struct sk_buff *skb)
 
 static void ath_rx_send_to_mac80211(struct ieee80211_hw *hw,
                                    struct ath_softc *sc, struct sk_buff *skb,
-                                   struct ieee80211_rx_status *rx_status)
+                                   struct ieee80211_rx_status *rxs)
 {
        struct ieee80211_hdr *hdr;
 
@@ -674,19 +672,14 @@ static void ath_rx_send_to_mac80211(struct ieee80211_hw *hw,
                        if (aphy == NULL)
                                continue;
                        nskb = skb_copy(skb, GFP_ATOMIC);
-                       if (nskb) {
-                               memcpy(IEEE80211_SKB_RXCB(nskb), rx_status,
-                                       sizeof(*rx_status));
-                               ieee80211_rx(aphy->hw, nskb);
-                       }
+                       if (!nskb)
+                               continue;
+                       ieee80211_rx(aphy->hw, nskb);
                }
-               memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
                ieee80211_rx(sc->hw, skb);
-       } else {
+       } else
                /* Deliver unicast frames based on receiver address */
-               memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
                ieee80211_rx(hw, skb);
-       }
 }
 
 int ath_rx_tasklet(struct ath_softc *sc, int flush)
@@ -699,7 +692,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
        struct ath_desc *ds;
        struct ath_rx_status *rx_stats;
        struct sk_buff *skb = NULL, *requeue_skb;
-       struct ieee80211_rx_status rx_status;
+       struct ieee80211_rx_status *rxs;
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
        /*
@@ -788,6 +781,8 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                                DMA_FROM_DEVICE);
 
                hdr = (struct ieee80211_hdr *) skb->data;
+               rxs =  IEEE80211_SKB_RXCB(skb);
+
                hw = ath_get_virt_hw(sc, hdr);
                rx_stats = &ds->ds_rxstat;
 
@@ -806,7 +801,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                        goto requeue;
 
                if (!ath_rx_prepare(common, hw, skb, rx_stats,
-                                   &rx_status, &decrypt_error))
+                                   rxs, &decrypt_error))
                        goto requeue;
 
                /* Ensure we always have an skb to requeue once we are done
@@ -848,20 +843,19 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                keyix = rx_stats->rs_keyix;
 
                if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error) {
-                       rx_status.flag |= RX_FLAG_DECRYPTED;
+                       rxs->flag |= RX_FLAG_DECRYPTED;
                } else if (ieee80211_has_protected(fc)
                           && !decrypt_error && skb->len >= hdrlen + 4) {
                        keyix = skb->data[hdrlen + 3] >> 6;
 
                        if (test_bit(keyix, sc->keymap))
-                               rx_status.flag |= RX_FLAG_DECRYPTED;
+                               rxs->flag |= RX_FLAG_DECRYPTED;
                }
                if (ah->sw_mgmt_crypto &&
-                   (rx_status.flag & RX_FLAG_DECRYPTED) &&
-                   ieee80211_is_mgmt(fc)) {
+                   (rxs->flag & RX_FLAG_DECRYPTED) &&
+                   ieee80211_is_mgmt(fc))
                        /* Use software decrypt for management frames. */
-                       rx_status.flag &= ~RX_FLAG_DECRYPTED;
-               }
+                       rxs->flag &= ~RX_FLAG_DECRYPTED;
 
                /* We will now give hardware our shiny new allocated skb */
                bf->bf_mpdu = requeue_skb;
@@ -874,7 +868,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                        bf->bf_mpdu = NULL;
                        ath_print(common, ATH_DBG_FATAL,
                                  "dma_mapping_error() on RX\n");
-                       ath_rx_send_to_mac80211(hw, sc, skb, &rx_status);
+                       ath_rx_send_to_mac80211(hw, sc, skb, rxs);
                        break;
                }
                bf->bf_dmacontext = bf->bf_buf_addr;
@@ -895,7 +889,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                                             SC_OP_WAIT_FOR_PSPOLL_DATA)))
                        ath_rx_ps(sc, skb);
 
-               ath_rx_send_to_mac80211(hw, sc, skb, &rx_status);
+               ath_rx_send_to_mac80211(hw, sc, skb, rxs);
 
 requeue:
                list_move_tail(&bf->list, &sc->rx.rxbuf);