root/drivers/net/wireless/marvell/mwifiex/uap_txrx.c

DEFINITIONS

1. mwifiex_uap_del_tx_pkts_in_ralist
2. mwifiex_uap_cleanup_tx_queues
3. mwifiex_uap_queue_bridged_pkt
4. mwifiex_handle_uap_rx_forward
5. mwifiex_uap_recv_packet
6. mwifiex_process_uap_rx_packet
7. mwifiex_process_uap_txpd

   1 /*
   2  * Marvell Wireless LAN device driver: AP TX and RX data handling
   3  *
   4  * Copyright (C) 2012-2014, Marvell International Ltd.
   5  *
   6  * This software file (the "File") is distributed by Marvell International
   7  * Ltd. under the terms of the GNU General Public License Version 2, June 1991
   8  * (the "License").  You may use, redistribute and/or modify this File in
   9  * accordance with the terms and conditions of the License, a copy of which
  10  * is available by writing to the Free Software Foundation, Inc.,
  11  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or on the
  12  * worldwide web at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
  13  *
  14  * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE EXPRESSLY DISCLAIMED.  The License provides additional details about
  17  * this warranty disclaimer.
  18  */
  19 
  20 #include "decl.h"
  21 #include "ioctl.h"
  22 #include "main.h"
  23 #include "wmm.h"
  24 #include "11n_aggr.h"
  25 #include "11n_rxreorder.h"
  26 
  27 /* This function checks if particular RA list has packets more than low bridge
  28  * packet threshold and then deletes packet from this RA list.
  29  * Function deletes packets from such RA list and returns true. If no such list
  30  * is found, false is returned.
  31  */
  32 static bool
  33 mwifiex_uap_del_tx_pkts_in_ralist(struct mwifiex_private *priv,
  34                                   struct list_head *ra_list_head,
  35                                   int tid)
  36 {
  37         struct mwifiex_ra_list_tbl *ra_list;
  38         struct sk_buff *skb, *tmp;
  39         bool pkt_deleted = false;
  40         struct mwifiex_txinfo *tx_info;
  41         struct mwifiex_adapter *adapter = priv->adapter;
  42 
  43         list_for_each_entry(ra_list, ra_list_head, list) {
  44                 if (skb_queue_empty(&ra_list->skb_head))
  45                         continue;
  46 
  47                 skb_queue_walk_safe(&ra_list->skb_head, skb, tmp) {
  48                         tx_info = MWIFIEX_SKB_TXCB(skb);
  49                         if (tx_info->flags & MWIFIEX_BUF_FLAG_BRIDGED_PKT) {
  50                                 __skb_unlink(skb, &ra_list->skb_head);
  51                                 mwifiex_write_data_complete(adapter, skb, 0,
  52                                                             -1);
  53                                 if (ra_list->tx_paused)
  54                                         priv->wmm.pkts_paused[tid]--;
  55                                 else
  56                                         atomic_dec(&priv->wmm.tx_pkts_queued);
  57                                 pkt_deleted = true;
  58                         }
  59                         if ((atomic_read(&adapter->pending_bridged_pkts) <=
  60                                              MWIFIEX_BRIDGED_PKTS_THR_LOW))
  61                                 break;
  62                 }
  63         }
  64 
  65         return pkt_deleted;
  66 }
  67 
  68 /* This function deletes packets from particular RA List. RA list index
  69  * from which packets are deleted is preserved so that packets from next RA
  70  * list are deleted upon subsequent call thus maintaining fairness.
  71  */
  72 static void mwifiex_uap_cleanup_tx_queues(struct mwifiex_private *priv)
  73 {
  74         struct list_head *ra_list;
  75         int i;
  76 
  77         spin_lock_bh(&priv->wmm.ra_list_spinlock);
  78 
  79         for (i = 0; i < MAX_NUM_TID; i++, priv->del_list_idx++) {
  80                 if (priv->del_list_idx == MAX_NUM_TID)
  81                         priv->del_list_idx = 0;
  82                 ra_list = &priv->wmm.tid_tbl_ptr[priv->del_list_idx].ra_list;
  83                 if (mwifiex_uap_del_tx_pkts_in_ralist(priv, ra_list, i)) {
  84                         priv->del_list_idx++;
  85                         break;
  86                 }
  87         }
  88 
  89         spin_unlock_bh(&priv->wmm.ra_list_spinlock);
  90 }
  91 
  92 
  93 static void mwifiex_uap_queue_bridged_pkt(struct mwifiex_private *priv,
  94                                          struct sk_buff *skb)
  95 {
  96         struct mwifiex_adapter *adapter = priv->adapter;
  97         struct uap_rxpd *uap_rx_pd;
  98         struct rx_packet_hdr *rx_pkt_hdr;
  99         struct sk_buff *new_skb;
 100         struct mwifiex_txinfo *tx_info;
 101         int hdr_chop;
 102         struct ethhdr *p_ethhdr;
 103         struct mwifiex_sta_node *src_node;
 104         int index;
 105 
 106         uap_rx_pd = (struct uap_rxpd *)(skb->data);
 107         rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);
 108 
 109         if ((atomic_read(&adapter->pending_bridged_pkts) >=
 110                                              MWIFIEX_BRIDGED_PKTS_THR_HIGH)) {
 111                 mwifiex_dbg(priv->adapter, ERROR,
 112                             "Tx: Bridge packet limit reached. Drop packet!\n");
 113                 kfree_skb(skb);
 114                 mwifiex_uap_cleanup_tx_queues(priv);
 115                 return;
 116         }
 117 
 118         if ((!memcmp(&rx_pkt_hdr->rfc1042_hdr, bridge_tunnel_header,
 119                      sizeof(bridge_tunnel_header))) ||
 120             (!memcmp(&rx_pkt_hdr->rfc1042_hdr, rfc1042_header,
 121                      sizeof(rfc1042_header)) &&
 122              ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_AARP &&
 123              ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_IPX)) {
 124                 /* Replace the 803 header and rfc1042 header (llc/snap) with
 125                  * an Ethernet II header, keep the src/dst and snap_type
 126                  * (ethertype).
 127                  *
 128                  * The firmware only passes up SNAP frames converting all RX
 129                  * data from 802.11 to 802.2/LLC/SNAP frames.
 130                  *
 131                  * To create the Ethernet II, just move the src, dst address
 132                  * right before the snap_type.
 133                  */
 134                 p_ethhdr = (struct ethhdr *)
 135                         ((u8 *)(&rx_pkt_hdr->eth803_hdr)
 136                          + sizeof(rx_pkt_hdr->eth803_hdr)
 137                          + sizeof(rx_pkt_hdr->rfc1042_hdr)
 138                          - sizeof(rx_pkt_hdr->eth803_hdr.h_dest)
 139                          - sizeof(rx_pkt_hdr->eth803_hdr.h_source)
 140                          - sizeof(rx_pkt_hdr->rfc1042_hdr.snap_type));
 141                 memcpy(p_ethhdr->h_source, rx_pkt_hdr->eth803_hdr.h_source,
 142                        sizeof(p_ethhdr->h_source));
 143                 memcpy(p_ethhdr->h_dest, rx_pkt_hdr->eth803_hdr.h_dest,
 144                        sizeof(p_ethhdr->h_dest));
 145                 /* Chop off the rxpd + the excess memory from
 146                  * 802.2/llc/snap header that was removed.
 147                  */
 148                 hdr_chop = (u8 *)p_ethhdr - (u8 *)uap_rx_pd;
 149         } else {
 150                 /* Chop off the rxpd */
 151                 hdr_chop = (u8 *)&rx_pkt_hdr->eth803_hdr - (u8 *)uap_rx_pd;
 152         }
 153 
 154         /* Chop off the leading header bytes so that it points
 155          * to the start of either the reconstructed EthII frame
 156          * or the 802.2/llc/snap frame.
 157          */
 158         skb_pull(skb, hdr_chop);
 159 
 160         if (skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN) {
 161                 mwifiex_dbg(priv->adapter, ERROR,
 162                             "data: Tx: insufficient skb headroom %d\n",
 163                             skb_headroom(skb));
 164                 /* Insufficient skb headroom - allocate a new skb */
 165                 new_skb =
 166                         skb_realloc_headroom(skb, MWIFIEX_MIN_DATA_HEADER_LEN);
 167                 if (unlikely(!new_skb)) {
 168                         mwifiex_dbg(priv->adapter, ERROR,
 169                                     "Tx: cannot allocate new_skb\n");
 170                         kfree_skb(skb);
 171                         priv->stats.tx_dropped++;
 172                         return;
 173                 }
 174 
 175                 kfree_skb(skb);
 176                 skb = new_skb;
 177                 mwifiex_dbg(priv->adapter, INFO,
 178                             "info: new skb headroom %d\n",
 179                             skb_headroom(skb));
 180         }
 181 
 182         tx_info = MWIFIEX_SKB_TXCB(skb);
 183         memset(tx_info, 0, sizeof(*tx_info));
 184         tx_info->bss_num = priv->bss_num;
 185         tx_info->bss_type = priv->bss_type;
 186         tx_info->flags |= MWIFIEX_BUF_FLAG_BRIDGED_PKT;
 187 
 188         src_node = mwifiex_get_sta_entry(priv, rx_pkt_hdr->eth803_hdr.h_source);
 189         if (src_node) {
 190                 src_node->stats.last_rx = jiffies;
 191                 src_node->stats.rx_bytes += skb->len;
 192                 src_node->stats.rx_packets++;
 193                 src_node->stats.last_tx_rate = uap_rx_pd->rx_rate;
 194                 src_node->stats.last_tx_htinfo = uap_rx_pd->ht_info;
 195         }
 196 
 197         if (is_unicast_ether_addr(rx_pkt_hdr->eth803_hdr.h_dest)) {
 198                 /* Update bridge packet statistics as the
 199                  * packet is not going to kernel/upper layer.
 200                  */
 201                 priv->stats.rx_bytes += skb->len;
 202                 priv->stats.rx_packets++;
 203 
 204                 /* Sending bridge packet to TX queue, so save the packet
 205                  * length in TXCB to update statistics in TX complete.
 206                  */
 207                 tx_info->pkt_len = skb->len;
 208         }
 209 
 210         __net_timestamp(skb);
 211 
 212         index = mwifiex_1d_to_wmm_queue[skb->priority];
 213         atomic_inc(&priv->wmm_tx_pending[index]);
 214         mwifiex_wmm_add_buf_txqueue(priv, skb);
 215         atomic_inc(&adapter->tx_pending);
 216         atomic_inc(&adapter->pending_bridged_pkts);
 217 
 218         mwifiex_queue_main_work(priv->adapter);
 219 
 220         return;
 221 }
 222 
 223 /*
 224  * This function contains logic for AP packet forwarding.
 225  *
 226  * If a packet is multicast/broadcast, it is sent to kernel/upper layer
 227  * as well as queued back to AP TX queue so that it can be sent to other
 228  * associated stations.
 229  * If a packet is unicast and RA is present in associated station list,
 230  * it is again requeued into AP TX queue.
 231  * If a packet is unicast and RA is not in associated station list,
 232  * packet is forwarded to kernel to handle routing logic.
 233  */
 234 int mwifiex_handle_uap_rx_forward(struct mwifiex_private *priv,
 235                                   struct sk_buff *skb)
 236 {
 237         struct mwifiex_adapter *adapter = priv->adapter;
 238         struct uap_rxpd *uap_rx_pd;
 239         struct rx_packet_hdr *rx_pkt_hdr;
 240         u8 ra[ETH_ALEN];
 241         struct sk_buff *skb_uap;
 242 
 243         uap_rx_pd = (struct uap_rxpd *)(skb->data);
 244         rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);
 245 
 246         /* don't do packet forwarding in disconnected state */
 247         if (!priv->media_connected) {
 248                 mwifiex_dbg(adapter, ERROR,
 249                             "drop packet in disconnected state.\n");
 250                 dev_kfree_skb_any(skb);
 251                 return 0;
 252         }
 253 
 254         memcpy(ra, rx_pkt_hdr->eth803_hdr.h_dest, ETH_ALEN);
 255 
 256         if (is_multicast_ether_addr(ra)) {
 257                 skb_uap = skb_copy(skb, GFP_ATOMIC);
 258                 mwifiex_uap_queue_bridged_pkt(priv, skb_uap);
 259         } else {
 260                 if (mwifiex_get_sta_entry(priv, ra)) {
 261                         /* Requeue Intra-BSS packet */
 262                         mwifiex_uap_queue_bridged_pkt(priv, skb);
 263                         return 0;
 264                 }
 265         }
 266 
 267         /* Forward unicat/Inter-BSS packets to kernel. */
 268         return mwifiex_process_rx_packet(priv, skb);
 269 }
 270 
 271 int mwifiex_uap_recv_packet(struct mwifiex_private *priv,
 272                             struct sk_buff *skb)
 273 {
 274         struct mwifiex_adapter *adapter = priv->adapter;
 275         struct mwifiex_sta_node *src_node;
 276         struct ethhdr *p_ethhdr;
 277         struct sk_buff *skb_uap;
 278         struct mwifiex_txinfo *tx_info;
 279 
 280         if (!skb)
 281                 return -1;
 282 
 283         p_ethhdr = (void *)skb->data;
 284         src_node = mwifiex_get_sta_entry(priv, p_ethhdr->h_source);
 285         if (src_node) {
 286                 src_node->stats.last_rx = jiffies;
 287                 src_node->stats.rx_bytes += skb->len;
 288                 src_node->stats.rx_packets++;
 289         }
 290 
 291         if (is_multicast_ether_addr(p_ethhdr->h_dest) ||
 292             mwifiex_get_sta_entry(priv, p_ethhdr->h_dest)) {
 293                 if (skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN)
 294                         skb_uap =
 295                         skb_realloc_headroom(skb, MWIFIEX_MIN_DATA_HEADER_LEN);
 296                 else
 297                         skb_uap = skb_copy(skb, GFP_ATOMIC);
 298 
 299                 if (likely(skb_uap)) {
 300                         tx_info = MWIFIEX_SKB_TXCB(skb_uap);
 301                         memset(tx_info, 0, sizeof(*tx_info));
 302                         tx_info->bss_num = priv->bss_num;
 303                         tx_info->bss_type = priv->bss_type;
 304                         tx_info->flags |= MWIFIEX_BUF_FLAG_BRIDGED_PKT;
 305                         __net_timestamp(skb_uap);
 306                         mwifiex_wmm_add_buf_txqueue(priv, skb_uap);
 307                         atomic_inc(&adapter->tx_pending);
 308                         atomic_inc(&adapter->pending_bridged_pkts);
 309                         if ((atomic_read(&adapter->pending_bridged_pkts) >=
 310                                         MWIFIEX_BRIDGED_PKTS_THR_HIGH)) {
 311                                 mwifiex_dbg(adapter, ERROR,
 312                                             "Tx: Bridge packet limit reached. Drop packet!\n");
 313                                 mwifiex_uap_cleanup_tx_queues(priv);
 314                         }
 315 
 316                 } else {
 317                         mwifiex_dbg(adapter, ERROR, "failed to allocate skb_uap");
 318                 }
 319 
 320                 mwifiex_queue_main_work(adapter);
 321                 /* Don't forward Intra-BSS unicast packet to upper layer*/
 322                 if (mwifiex_get_sta_entry(priv, p_ethhdr->h_dest))
 323                         return 0;
 324         }
 325 
 326         skb->dev = priv->netdev;
 327         skb->protocol = eth_type_trans(skb, priv->netdev);
 328         skb->ip_summed = CHECKSUM_NONE;
 329 
 330         /* This is required only in case of 11n and USB/PCIE as we alloc
 331          * a buffer of 4K only if its 11N (to be able to receive 4K
 332          * AMSDU packets). In case of SD we allocate buffers based
 333          * on the size of packet and hence this is not needed.
 334          *
 335          * Modifying the truesize here as our allocation for each
 336          * skb is 4K but we only receive 2K packets and this cause
 337          * the kernel to start dropping packets in case where
 338          * application has allocated buffer based on 2K size i.e.
 339          * if there a 64K packet received (in IP fragments and
 340          * application allocates 64K to receive this packet but
 341          * this packet would almost double up because we allocate
 342          * each 1.5K fragment in 4K and pass it up. As soon as the
 343          * 64K limit hits kernel will start to drop rest of the
 344          * fragments. Currently we fail the Filesndl-ht.scr script
 345          * for UDP, hence this fix
 346          */
 347         if ((adapter->iface_type == MWIFIEX_USB ||
 348              adapter->iface_type == MWIFIEX_PCIE) &&
 349             skb->truesize > MWIFIEX_RX_DATA_BUF_SIZE)
 350                 skb->truesize += (skb->len - MWIFIEX_RX_DATA_BUF_SIZE);
 351 
 352         /* Forward multicast/broadcast packet to upper layer*/
 353         if (in_interrupt())
 354                 netif_rx(skb);
 355         else
 356                 netif_rx_ni(skb);
 357 
 358         return 0;
 359 }
 360 
 361 /*
 362  * This function processes the packet received on AP interface.
 363  *
 364  * The function looks into the RxPD and performs sanity tests on the
 365  * received buffer to ensure its a valid packet before processing it
 366  * further. If the packet is determined to be aggregated, it is
 367  * de-aggregated accordingly. Then skb is passed to AP packet forwarding logic.
 368  *
 369  * The completion callback is called after processing is complete.
 370  */
 371 int mwifiex_process_uap_rx_packet(struct mwifiex_private *priv,
 372                                   struct sk_buff *skb)
 373 {
 374         struct mwifiex_adapter *adapter = priv->adapter;
 375         int ret;
 376         struct uap_rxpd *uap_rx_pd;
 377         struct rx_packet_hdr *rx_pkt_hdr;
 378         u16 rx_pkt_type;
 379         u8 ta[ETH_ALEN], pkt_type;
 380         struct mwifiex_sta_node *node;
 381 
 382         uap_rx_pd = (struct uap_rxpd *)(skb->data);
 383         rx_pkt_type = le16_to_cpu(uap_rx_pd->rx_pkt_type);
 384         rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);
 385 
 386         ether_addr_copy(ta, rx_pkt_hdr->eth803_hdr.h_source);
 387 
 388         if ((le16_to_cpu(uap_rx_pd->rx_pkt_offset) +
 389              le16_to_cpu(uap_rx_pd->rx_pkt_length)) > (u16) skb->len) {
 390                 mwifiex_dbg(adapter, ERROR,
 391                             "wrong rx packet: len=%d, offset=%d, length=%d\n",
 392                             skb->len, le16_to_cpu(uap_rx_pd->rx_pkt_offset),
 393                             le16_to_cpu(uap_rx_pd->rx_pkt_length));
 394                 priv->stats.rx_dropped++;
 395 
 396                 node = mwifiex_get_sta_entry(priv, ta);
 397                 if (node)
 398                         node->stats.tx_failed++;
 399 
 400                 dev_kfree_skb_any(skb);
 401                 return 0;
 402         }
 403 
 404         if (rx_pkt_type == PKT_TYPE_MGMT) {
 405                 ret = mwifiex_process_mgmt_packet(priv, skb);
 406                 if (ret)
 407                         mwifiex_dbg(adapter, DATA, "Rx of mgmt packet failed");
 408                 dev_kfree_skb_any(skb);
 409                 return ret;
 410         }
 411 
 412 
 413         if (rx_pkt_type != PKT_TYPE_BAR && uap_rx_pd->priority < MAX_NUM_TID) {
 414                 spin_lock_bh(&priv->sta_list_spinlock);
 415                 node = mwifiex_get_sta_entry(priv, ta);
 416                 if (node)
 417                         node->rx_seq[uap_rx_pd->priority] =
 418                                                 le16_to_cpu(uap_rx_pd->seq_num);
 419                 spin_unlock_bh(&priv->sta_list_spinlock);
 420         }
 421 
 422         if (!priv->ap_11n_enabled ||
 423             (!mwifiex_11n_get_rx_reorder_tbl(priv, uap_rx_pd->priority, ta) &&
 424             (le16_to_cpu(uap_rx_pd->rx_pkt_type) != PKT_TYPE_AMSDU))) {
 425                 ret = mwifiex_handle_uap_rx_forward(priv, skb);
 426                 return ret;
 427         }
 428 
 429         /* Reorder and send to kernel */
 430         pkt_type = (u8)le16_to_cpu(uap_rx_pd->rx_pkt_type);
 431         ret = mwifiex_11n_rx_reorder_pkt(priv, le16_to_cpu(uap_rx_pd->seq_num),
 432                                          uap_rx_pd->priority, ta, pkt_type,
 433                                          skb);
 434 
 435         if (ret || (rx_pkt_type == PKT_TYPE_BAR))
 436                 dev_kfree_skb_any(skb);
 437 
 438         if (ret)
 439                 priv->stats.rx_dropped++;
 440 
 441         return ret;
 442 }
 443 
 444 /*
 445  * This function fills the TxPD for AP tx packets.
 446  *
 447  * The Tx buffer received by this function should already have the
 448  * header space allocated for TxPD.
 449  *
 450  * This function inserts the TxPD in between interface header and actual
 451  * data and adjusts the buffer pointers accordingly.
 452  *
 453  * The following TxPD fields are set by this function, as required -
 454  *      - BSS number
 455  *      - Tx packet length and offset
 456  *      - Priority
 457  *      - Packet delay
 458  *      - Priority specific Tx control
 459  *      - Flags
 460  */
 461 void *mwifiex_process_uap_txpd(struct mwifiex_private *priv,
 462                                struct sk_buff *skb)
 463 {
 464         struct mwifiex_adapter *adapter = priv->adapter;
 465         struct uap_txpd *txpd;
 466         struct mwifiex_txinfo *tx_info = MWIFIEX_SKB_TXCB(skb);
 467         int pad;
 468         u16 pkt_type, pkt_offset;
 469         int hroom = adapter->intf_hdr_len;
 470 
 471         if (!skb->len) {
 472                 mwifiex_dbg(adapter, ERROR,
 473                             "Tx: bad packet length: %d\n", skb->len);
 474                 tx_info->status_code = -1;
 475                 return skb->data;
 476         }
 477 
 478         BUG_ON(skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN);
 479 
 480         pkt_type = mwifiex_is_skb_mgmt_frame(skb) ? PKT_TYPE_MGMT : 0;
 481 
 482         pad = ((void *)skb->data - (sizeof(*txpd) + hroom) - NULL) &
 483                         (MWIFIEX_DMA_ALIGN_SZ - 1);
 484 
 485         skb_push(skb, sizeof(*txpd) + pad);
 486 
 487         txpd = (struct uap_txpd *)skb->data;
 488         memset(txpd, 0, sizeof(*txpd));
 489         txpd->bss_num = priv->bss_num;
 490         txpd->bss_type = priv->bss_type;
 491         txpd->tx_pkt_length = cpu_to_le16((u16)(skb->len - (sizeof(*txpd) +
 492                                                 pad)));
 493         txpd->priority = (u8)skb->priority;
 494 
 495         txpd->pkt_delay_2ms = mwifiex_wmm_compute_drv_pkt_delay(priv, skb);
 496 
 497         if (tx_info->flags & MWIFIEX_BUF_FLAG_EAPOL_TX_STATUS ||
 498             tx_info->flags & MWIFIEX_BUF_FLAG_ACTION_TX_STATUS) {
 499                 txpd->tx_token_id = tx_info->ack_frame_id;
 500                 txpd->flags |= MWIFIEX_TXPD_FLAGS_REQ_TX_STATUS;
 501         }
 502 
 503         if (txpd->priority < ARRAY_SIZE(priv->wmm.user_pri_pkt_tx_ctrl))
 504                 /*
 505                  * Set the priority specific tx_control field, setting of 0 will
 506                  * cause the default value to be used later in this function.
 507                  */
 508                 txpd->tx_control =
 509                     cpu_to_le32(priv->wmm.user_pri_pkt_tx_ctrl[txpd->priority]);
 510 
 511         /* Offset of actual data */
 512         pkt_offset = sizeof(*txpd) + pad;
 513         if (pkt_type == PKT_TYPE_MGMT) {
 514                 /* Set the packet type and add header for management frame */
 515                 txpd->tx_pkt_type = cpu_to_le16(pkt_type);
 516                 pkt_offset += MWIFIEX_MGMT_FRAME_HEADER_SIZE;
 517         }
 518 
 519         txpd->tx_pkt_offset = cpu_to_le16(pkt_offset);
 520 
 521         /* make space for adapter->intf_hdr_len */
 522         skb_push(skb, hroom);
 523 
 524         if (!txpd->tx_control)
 525                 /* TxCtrl set by user or default */
 526                 txpd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);
 527 
 528         return skb->data;
 529 }