iwlwifi: remove skb_linearize for rx frames

Remove skb_linearize() in the iwlwifi drivers since
mac80211 supports paged rx SKBs now.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-3945.c

@@ -548,7 +548,6 @@ static void iwl3945_pass_packet_to_mac80211(struct iwl_priv *priv,
 	struct iwl3945_rx_frame_end *rx_end = IWL_RX_END(pkt);
 	u16 len = le16_to_cpu(rx_hdr->len);
 	struct sk_buff *skb;
-	int ret;
 	__le16 fc = hdr->frame_control;
 
 	/* We received data from the HW, so stop the watchdog */
@@ -565,9 +564,9 @@ static void iwl3945_pass_packet_to_mac80211(struct iwl_priv *priv,
 		return;
 	}
 
-	skb = alloc_skb(IWL_LINK_HDR_MAX * 2, GFP_ATOMIC);
+	skb = dev_alloc_skb(128);
 	if (!skb) {
-		IWL_ERR(priv, "alloc_skb failed\n");
+		IWL_ERR(priv, "dev_alloc_skb failed\n");
 		return;
 	}
 
@@ -576,37 +575,13 @@ static void iwl3945_pass_packet_to_mac80211(struct iwl_priv *priv,
 				       (struct ieee80211_hdr *)rxb_addr(rxb),
 				       le32_to_cpu(rx_end->status), stats);
 
-	skb_reserve(skb, IWL_LINK_HDR_MAX);
 	skb_add_rx_frag(skb, 0, rxb->page,
 			(void *)rx_hdr->payload - (void *)pkt, len);
 
-	/* mac80211 currently doesn't support paged SKB. Convert it to
-	 * linear SKB for management frame and data frame requires
-	 * software decryption or software defragementation. */
-	if (ieee80211_is_mgmt(fc) ||
-	    ieee80211_has_protected(fc) ||
-	    ieee80211_has_morefrags(fc) ||
-	    le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG)
-		ret = skb_linearize(skb);
-	else
-		ret = __pskb_pull_tail(skb, min_t(u16, IWL_LINK_HDR_MAX, len)) ?
-			0 : -ENOMEM;
-
-	if (ret) {
-		kfree_skb(skb);
-		goto out;
-	}
-
-	/*
-	 * XXX: We cannot touch the page and its virtual memory (pkt) after
-	 * here. It might have already been freed by the above skb change.
-	 */
-
 	iwl_update_stats(priv, false, fc, len);
 	memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));
 
 	ieee80211_rx(priv->hw, skb);
- out:
 	priv->alloc_rxb_page--;
 	rxb->page = NULL;
 }

drivers/net/wireless/iwlwifi/iwl-agn-lib.c

@@ -931,7 +931,6 @@ static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv,
 					struct ieee80211_rx_status *stats)
 {
 	struct sk_buff *skb;
-	int ret = 0;
 	__le16 fc = hdr->frame_control;
 
 	/* We only process data packets if the interface is open */
@@ -946,45 +945,18 @@ static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv,
 	    iwl_set_decrypted_flag(priv, hdr, ampdu_status, stats))
 		return;
 
-	skb = alloc_skb(IWL_LINK_HDR_MAX * 2, GFP_ATOMIC);
+	skb = dev_alloc_skb(128);
 	if (!skb) {
-		IWL_ERR(priv, "alloc_skb failed\n");
+		IWL_ERR(priv, "dev_alloc_skb failed\n");
 		return;
 	}
 
-	skb_reserve(skb, IWL_LINK_HDR_MAX);
 	skb_add_rx_frag(skb, 0, rxb->page, (void *)hdr - rxb_addr(rxb), len);
 
-	/* mac80211 currently doesn't support paged SKB. Convert it to
-	 * linear SKB for management frame and data frame requires
-	 * software decryption or software defragementation. */
-	if (ieee80211_is_mgmt(fc) ||
-	    ieee80211_has_protected(fc) ||
-	    ieee80211_has_morefrags(fc) ||
-	    le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG ||
-	    (ieee80211_is_data_qos(fc) &&
-	     *ieee80211_get_qos_ctl(hdr) &
-	     IEEE80211_QOS_CONTROL_A_MSDU_PRESENT))
-		ret = skb_linearize(skb);
-	else
-		ret = __pskb_pull_tail(skb, min_t(u16, IWL_LINK_HDR_MAX, len)) ?
-			 0 : -ENOMEM;
-
-	if (ret) {
-		kfree_skb(skb);
-		goto out;
-	}
-
-	/*
-	 * XXX: We cannot touch the page and its virtual memory (hdr) after
-	 * here. It might have already been freed by the above skb change.
-	 */
-
 	iwl_update_stats(priv, false, fc, len);
 	memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));
 
 	ieee80211_rx(priv->hw, skb);
- out:
 	priv->alloc_rxb_page--;
 	rxb->page = NULL;
 }

drivers/net/wireless/iwlwifi/iwl-dev.h

@@ -325,13 +325,6 @@ enum {
 
 #define DEF_CMD_PAYLOAD_SIZE 320
 
-/*
- * IWL_LINK_HDR_MAX should include ieee80211_hdr, radiotap header,
- * SNAP header and alignment. It should also be big enough for 802.11
- * control frames.
- */
-#define IWL_LINK_HDR_MAX 64
-
 /**
  * struct iwl_device_cmd
  *