ath10k: support msdu chaining

Consolidate the list of msdu skbs into the msdu-head skb, delete the
rest of the skbs, pass the msdu-head skb on up the stack as normal.

Tested with high-speed TCP and UDP traffic on modified firmware that
supports raw-rx.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c b/drivers/net/wireless/ath/ath10k/htt_rx.c
index 36a3871..cdcbe2d 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/htt_rx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
@@ -398,6 +398,7 @@ static int ath10k_htt_rx_amsdu_pop(struct ath10k_htt *htt,
                msdu_len = MS(__le32_to_cpu(rx_desc->msdu_start.info0),
                              RX_MSDU_START_INFO0_MSDU_LENGTH);
                msdu_chained = rx_desc->frag_info.ring2_more_count;
+               msdu_chaining = msdu_chained;
 
                if (msdu_len_invalid)
                        msdu_len = 0;
@@ -425,7 +426,6 @@ static int ath10k_htt_rx_amsdu_pop(struct ath10k_htt *htt,
 
                        msdu->next = next;
                        msdu = next;
-                       msdu_chaining = 1;
                }
 
                last_msdu = __le32_to_cpu(rx_desc->msdu_end.info0) &
@@ -901,6 +901,57 @@ static int ath10k_htt_rx_get_csum_state(struct sk_buff *skb)
        return CHECKSUM_UNNECESSARY;
 }
 
+static int ath10k_unchain_msdu(struct sk_buff *msdu_head)
+{
+       struct sk_buff *next = msdu_head->next;
+       struct sk_buff *to_free = next;
+       int space;
+       int total_len = 0;
+
+       /* TODO:  Might could optimize this by using
+        * skb_try_coalesce or similar method to
+        * decrease copying, or maybe get mac80211 to
+        * provide a way to just receive a list of
+        * skb?
+        */
+
+       msdu_head->next = NULL;
+
+       /* Allocate total length all at once. */
+       while (next) {
+               total_len += next->len;
+               next = next->next;
+       }
+
+       space = total_len - skb_tailroom(msdu_head);
+       if ((space > 0) &&
+           (pskb_expand_head(msdu_head, 0, space, GFP_ATOMIC) < 0)) {
+               /* TODO:  bump some rx-oom error stat */
+               /* put it back together so we can free the
+                * whole list at once.
+                */
+               msdu_head->next = to_free;
+               return -1;
+       }
+
+       /* Walk list again, copying contents into
+        * msdu_head
+        */
+       next = to_free;
+       while (next) {
+               skb_copy_from_linear_data(next, skb_put(msdu_head, next->len),
+                                         next->len);
+               next = next->next;
+       }
+
+       /* If here, we have consolidated skb.  Free the
+        * fragments and pass the main skb on up the
+        * stack.
+        */
+       ath10k_htt_rx_free_msdu_chain(to_free);
+       return 0;
+}
+
 static void ath10k_htt_rx_handler(struct ath10k_htt *htt,
                                  struct htt_rx_indication *rx)
 {
@@ -991,10 +1042,8 @@ static void ath10k_htt_rx_handler(struct ath10k_htt *htt,
                                continue;
                        }
 
-                       /* FIXME: we do not support chaining yet.
-                        * this needs investigation */
-                       if (msdu_chaining) {
-                               ath10k_warn("htt rx msdu_chaining is true\n");
+                       if (msdu_chaining &&
+                           (ath10k_unchain_msdu(msdu_head) < 0)) {
                                ath10k_htt_rx_free_msdu_chain(msdu_head);
                                continue;
                        }