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Commit 3771a890 authored by Johannes Berg's avatar Johannes Berg Committed by Emmanuel Grumbach
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iwlwifi: mvm: pull SNAP header into skb->head 



When we pre-populate the skb->head for the stack, we only pull
in the 802.11 header including crypto (assuming the packet isn't
short enough to be in there completely.) This is fine, but in
ieee80211_data_to_8023() we later unconditionally pull 8 more
bytes for the SNAP header and ethertype field (except for mesh
or 4-addr, where it's even more, but we don't care as much about
them).

Avoid the additional later pull by pulling in those 8 bytes here.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Reviewed-by: default avatarIdoX Yariv <ido@wizery.com>
Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
parent eb96ccb1

drivers/net/wireless/iwlwifi/mvm/rx.c

+12 −3
Original line number Diff line number Diff line
@@ -104,10 +104,19 @@ static void iwl_mvm_pass_packet_to_mac80211(struct iwl_mvm *mvm, 
	unsigned int hdrlen, fraglen;



	/* If frame is small enough to fit in skb->head, pull it completely.

	 * If not, only pull ieee80211_hdr (including crypto if present) so

	 * that splice() or TCP coalesce are more efficient.

	 * If not, only pull ieee80211_hdr (including crypto if present, and

	 * an additional 8 bytes for SNAP/ethertype, see below) so that

	 * splice() or TCP coalesce are more efficient.

	 *

	 * Since, in addition, ieee80211_data_to_8023() always pull in at

	 * least 8 bytes (possibly more for mesh) we can do the same here

	 * to save the cost of doing it later. That still doesn't pull in

	 * the actual IP header since the typical case has a SNAP header.

	 * If the latter changes (there are efforts in the standards group

	 * to do so) we should revisit this and ieee80211_data_to_8023().

	 */

	hdrlen = (len <= skb_tailroom(skb)) ? len : sizeof(*hdr) + crypt_len;

	hdrlen = (len <= skb_tailroom(skb)) ? len :

					      sizeof(*hdr) + crypt_len + 8;



	memcpy(skb_put(skb, hdrlen), hdr, hdrlen);

	fraglen = len - hdrlen;