ath10k: report A-MSDU subframes individually

HW reports each A-MSDU subframe as a separate
sk_buff. It is impossible to configure it to
behave differently.

Until now ath10k was reconstructing A-MSDUs from
subframes which involved a lot of memory
operations. This proved to be a significant
contributor to degraded RX performance.

Signed-off-by: Michal Kazior <michal.kazior@tieto.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 62ea9c8f80c417060c042d311a34415c271c176c..617df96e4ffd422e7cc12652b5d5671f259d6e31 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/htt_rx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
@@ -41,6 +41,10 @@
 /* when under memory pressure rx ring refill may fail and needs a retry */
 #define HTT_RX_RING_REFILL_RETRY_MS 50
 
+
+static int ath10k_htt_rx_get_csum_state(struct sk_buff *skb);
+
+
 static int ath10k_htt_rx_ring_size(struct ath10k_htt *htt)
 {
        int size;
@@ -591,136 +595,111 @@ static bool ath10k_htt_rx_hdr_is_amsdu(struct ieee80211_hdr *hdr)
        return false;
 }
 
-static int ath10k_htt_rx_amsdu(struct ath10k_htt *htt,
-                       struct htt_rx_info *info)
+struct rfc1042_hdr {
+       u8 llc_dsap;
+       u8 llc_ssap;
+       u8 llc_ctrl;
+       u8 snap_oui[3];
+       __be16 snap_type;
+} __packed;
+
+struct amsdu_subframe_hdr {
+       u8 dst[ETH_ALEN];
+       u8 src[ETH_ALEN];
+       __be16 len;
+} __packed;
+
+static void ath10k_htt_rx_amsdu(struct ath10k_htt *htt,
+                               struct htt_rx_info *info)
 {
        struct htt_rx_desc *rxd;
-       struct sk_buff *amsdu;
        struct sk_buff *first;
-       struct ieee80211_hdr *hdr;
        struct sk_buff *skb = info->skb;
        enum rx_msdu_decap_format fmt;
        enum htt_rx_mpdu_encrypt_type enctype;
+       struct ieee80211_hdr *hdr;
+       u8 hdr_buf[64];
        unsigned int hdr_len;
-       int crypto_len;
 
        rxd = (void *)skb->data - sizeof(*rxd);
-       fmt = MS(__le32_to_cpu(rxd->msdu_start.info1),
-                       RX_MSDU_START_INFO1_DECAP_FORMAT);
        enctype = MS(__le32_to_cpu(rxd->mpdu_start.info0),
                        RX_MPDU_START_INFO0_ENCRYPT_TYPE);
 
-       /* FIXME: No idea what assumptions are safe here. Need logs */
-       if ((fmt == RX_MSDU_DECAP_RAW && skb->next)) {
-               ath10k_htt_rx_free_msdu_chain(skb->next);
-               skb->next = NULL;
-               return -ENOTSUPP;
-       }
+       hdr = (struct ieee80211_hdr *)rxd->rx_hdr_status;
+       hdr_len = ieee80211_hdrlen(hdr->frame_control);
+       memcpy(hdr_buf, hdr, hdr_len);
+       hdr = (struct ieee80211_hdr *)hdr_buf;
 
-       /* A-MSDU max is a little less than 8K */
-       amsdu = dev_alloc_skb(8*1024);
-       if (!amsdu) {
-               ath10k_warn("A-MSDU allocation failed\n");
-               ath10k_htt_rx_free_msdu_chain(skb->next);
-               skb->next = NULL;
-               return -ENOMEM;
-       }
-
-       if (fmt >= RX_MSDU_DECAP_NATIVE_WIFI) {
-               int hdrlen;
-
-               hdr = (void *)rxd->rx_hdr_status;
-               hdrlen = ieee80211_hdrlen(hdr->frame_control);
-               memcpy(skb_put(amsdu, hdrlen), hdr, hdrlen);
-       }
+       /* FIXME: Hopefully this is a temporary measure.
+        *
+        * Reporting individual A-MSDU subframes means each reported frame
+        * shares the same sequence number.
+        *
+        * mac80211 drops frames it recognizes as duplicates, i.e.
+        * retransmission flag is set and sequence number matches sequence
+        * number from a previous frame (as per IEEE 802.11-2012: 9.3.2.10
+        * "Duplicate detection and recovery")
+        *
+        * To avoid frames being dropped clear retransmission flag for all
+        * received A-MSDUs.
+        *
+        * Worst case: actual duplicate frames will be reported but this should
+        * still be handled gracefully by other OSI/ISO layers. */
+       hdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_RETRY);
 
        first = skb;
        while (skb) {
                void *decap_hdr;
-               int decap_len = 0;
+               int len;
 
                rxd = (void *)skb->data - sizeof(*rxd);
                fmt = MS(__le32_to_cpu(rxd->msdu_start.info1),
-                               RX_MSDU_START_INFO1_DECAP_FORMAT);
+                        RX_MSDU_START_INFO1_DECAP_FORMAT);
                decap_hdr = (void *)rxd->rx_hdr_status;
 
-               if (skb == first) {
-                       /* We receive linked A-MSDU subframe skbuffs. The
-                        * first one contains the original 802.11 header (and
-                        * possible crypto param) in the RX descriptor. The
-                        * A-MSDU subframe header follows that. Each part is
-                        * aligned to 4 byte boundary. */
-
-                       hdr = (void *)amsdu->data;
-                       hdr_len = ieee80211_hdrlen(hdr->frame_control);
-                       crypto_len = ath10k_htt_rx_crypto_param_len(enctype);
-
-                       decap_hdr += roundup(hdr_len, 4);
-                       decap_hdr += roundup(crypto_len, 4);
-               }
-
-               /* When fmt == RX_MSDU_DECAP_8023_SNAP_LLC:
-                *
-                * SNAP 802.3 consists of:
-                * [dst:6][src:6][len:2][dsap:1][ssap:1][ctl:1][snap:5]
-                * [data][fcs:4].
-                *
-                * Since this overlaps with A-MSDU header (da, sa, len)
-                * there's nothing extra to do. */
-
-               if (fmt == RX_MSDU_DECAP_ETHERNET2_DIX) {
-                       /* Ethernet2 decap inserts ethernet header in place of
-                        * A-MSDU subframe header. */
-                       skb_pull(skb, 6 + 6 + 2);
-
-                       /* A-MSDU subframe header length */
-                       decap_len += 6 + 6 + 2;
-
-                       /* Ethernet2 decap also strips the LLC/SNAP so we need
-                        * to re-insert it. The LLC/SNAP follows A-MSDU
-                        * subframe header. */
-                       /* FIXME: Not all LLCs are 8 bytes long */
-                       decap_len += 8;
-
-                       memcpy(skb_put(amsdu, decap_len), decap_hdr, decap_len);
-               }
+               skb->ip_summed = ath10k_htt_rx_get_csum_state(skb);
 
-               if (fmt == RX_MSDU_DECAP_NATIVE_WIFI) {
-                       /* Native Wifi decap inserts regular 802.11 header
-                        * in place of A-MSDU subframe header. */
-                       hdr = (struct ieee80211_hdr *)skb->data;
-                       skb_pull(skb, ieee80211_hdrlen(hdr->frame_control));
-
-                       /* A-MSDU subframe header length */
-                       decap_len += 6 + 6 + 2;
-
-                       memcpy(skb_put(amsdu, decap_len), decap_hdr, decap_len);
+               /* First frame in an A-MSDU chain has more decapped data. */
+               if (skb == first) {
+                       len = round_up(ieee80211_hdrlen(hdr->frame_control), 4);
+                       len += round_up(ath10k_htt_rx_crypto_param_len(enctype),
+                                       4);
+                       decap_hdr += len;
                }
 
-               if (fmt == RX_MSDU_DECAP_RAW)
-                       skb_trim(skb, skb->len - 4); /* remove FCS */
-
-               memcpy(skb_put(amsdu, skb->len), skb->data, skb->len);
-
-               /* A-MSDU subframes are padded to 4bytes
-                * but relative to first subframe, not the whole MPDU */
-               if (skb->next && ((decap_len + skb->len) & 3)) {
-                       int padlen = 4 - ((decap_len + skb->len) & 3);
-                       memset(skb_put(amsdu, padlen), 0, padlen);
+               switch (fmt) {
+               case RX_MSDU_DECAP_RAW:
+                       skb_trim(skb, skb->len - FCS_LEN);
+                       break;
+               case RX_MSDU_DECAP_NATIVE_WIFI:
+                       break;
+               case RX_MSDU_DECAP_ETHERNET2_DIX:
+                       len = 0;
+                       len += sizeof(struct rfc1042_hdr);
+                       len += sizeof(struct amsdu_subframe_hdr);
+
+                       skb_pull(skb, sizeof(struct ethhdr));
+                       memcpy(skb_push(skb, len), decap_hdr, len);
+                       memcpy(skb_push(skb, hdr_len), hdr, hdr_len);
+                       break;
+               case RX_MSDU_DECAP_8023_SNAP_LLC:
+                       memcpy(skb_push(skb, hdr_len), hdr, hdr_len);
+                       break;
                }
 
+               info->skb = skb;
+               info->encrypt_type = enctype;
                skb = skb->next;
-       }
-
-       info->skb = amsdu;
-       info->encrypt_type = enctype;
+               info->skb->next = NULL;
 
-       ath10k_htt_rx_free_msdu_chain(first);
+               ath10k_process_rx(htt->ar, info);
+       }
 
-       return 0;
+       /* FIXME: It might be nice to re-assemble the A-MSDU when there's a
+        * monitor interface active for sniffing purposes. */
 }
 
-static int ath10k_htt_rx_msdu(struct ath10k_htt *htt, struct htt_rx_info *info)
+static void ath10k_htt_rx_msdu(struct ath10k_htt *htt, struct htt_rx_info *info)
 {
        struct sk_buff *skb = info->skb;
        struct htt_rx_desc *rxd;
@@ -742,6 +721,8 @@ static int ath10k_htt_rx_msdu(struct ath10k_htt *htt, struct htt_rx_info *info)
                        RX_MPDU_START_INFO0_ENCRYPT_TYPE);
        hdr = (void *)skb->data - RX_HTT_HDR_STATUS_LEN;
 
+       skb->ip_summed = ath10k_htt_rx_get_csum_state(skb);
+
        switch (fmt) {
        case RX_MSDU_DECAP_RAW:
                /* remove trailing FCS */
@@ -782,7 +763,8 @@ static int ath10k_htt_rx_msdu(struct ath10k_htt *htt, struct htt_rx_info *info)
 
        info->skb = skb;
        info->encrypt_type = enctype;
-       return 0;
+
+       ath10k_process_rx(htt->ar, info);
 }
 
 static bool ath10k_htt_rx_has_decrypt_err(struct sk_buff *skb)
@@ -854,8 +836,6 @@ static void ath10k_htt_rx_handler(struct ath10k_htt *htt,
        int fw_desc_len;
        u8 *fw_desc;
        int i, j;
-       int ret;
-       int ip_summed;
 
        memset(&info, 0, sizeof(info));
 
@@ -930,11 +910,6 @@ static void ath10k_htt_rx_handler(struct ath10k_htt *htt,
                                continue;
                        }
 
-                       /* The skb is not yet processed and it may be
-                        * reallocated. Since the offload is in the original
-                        * skb extract the checksum now and assign it later */
-                       ip_summed = ath10k_htt_rx_get_csum_state(msdu_head);
-
                        info.skb     = msdu_head;
                        info.fcs_err = ath10k_htt_rx_has_fcs_err(msdu_head);
                        info.signal  = ATH10K_DEFAULT_NOISE_FLOOR;
@@ -947,24 +922,9 @@ static void ath10k_htt_rx_handler(struct ath10k_htt *htt,
                        hdr = ath10k_htt_rx_skb_get_hdr(msdu_head);
 
                        if (ath10k_htt_rx_hdr_is_amsdu(hdr))
-                               ret = ath10k_htt_rx_amsdu(htt, &info);
+                               ath10k_htt_rx_amsdu(htt, &info);
                        else
-                               ret = ath10k_htt_rx_msdu(htt, &info);
-
-                       if (ret && !info.fcs_err) {
-                               ath10k_warn("error processing msdus %d\n", ret);
-                               dev_kfree_skb_any(info.skb);
-                               continue;
-                       }
-
-                       if (ath10k_htt_rx_hdr_is_amsdu((void *)info.skb->data))
-                               ath10k_dbg(ATH10K_DBG_HTT, "htt mpdu is amsdu\n");
-
-                       info.skb->ip_summed = ip_summed;
-
-                       ath10k_dbg_dump(ATH10K_DBG_HTT_DUMP, NULL, "htt mpdu: ",
-                                       info.skb->data, info.skb->len);
-                       ath10k_process_rx(htt->ar, &info);
+                               ath10k_htt_rx_msdu(htt, &info);
                }
        }
 

diff --git a/drivers/net/wireless/ath/ath10k/txrx.c b/drivers/net/wireless/ath/ath10k/txrx.c
index 57931d0fae4b0c1e26167ea378118b16e177f173..5ae373a1e2942fbcb3d185533d41eaf9dd8e24bd 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/txrx.c
+++ b/drivers/net/wireless/ath/ath10k/txrx.c
@@ -268,6 +268,8 @@ void ath10k_process_rx(struct ath10k *ar, struct htt_rx_info *info)
                   status->vht_nss,
                   status->freq,
                   status->band);
+       ath10k_dbg_dump(ATH10K_DBG_HTT_DUMP, NULL, "rx skb: ",
+                       info->skb->data, info->skb->len);
 
        ieee80211_rx(ar->hw, info->skb);
 }