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Commit 657e2765 authored by Jussi Kivilinna's avatar Jussi Kivilinna Committed by John W. Linville
Browse files

rtlwifi: usb: add NET_IP_ALIGN padding to RX skb when needed 



Add proper alignment at first packet copy, to avoid extra copies made later
in networking stack.

Signed-off-by: default avatarJussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 29bb7013

drivers/net/wireless/rtlwifi/usb.c

+40 −1
Original line number Diff line number Diff line
@@ -569,6 +569,37 @@ static void _rtl_rx_work(unsigned long param) 
	}

}



static unsigned int _rtl_rx_get_padding(struct ieee80211_hdr *hdr,

					unsigned int len)

{

	unsigned int padding = 0;



	/* make function no-op when possible */

	if (NET_IP_ALIGN == 0 || len < sizeof(*hdr))

		return 0;



	/* alignment calculation as in lbtf_rx() / carl9170_rx_copy_data() */

	/* TODO: deduplicate common code, define helper function instead? */



	if (ieee80211_is_data_qos(hdr->frame_control)) {

		u8 *qc = ieee80211_get_qos_ctl(hdr);



		padding ^= NET_IP_ALIGN;



		/* Input might be invalid, avoid accessing memory outside

		 * the buffer.

		 */

		if ((unsigned long)qc - (unsigned long)hdr < len &&

		    *qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)

			padding ^= NET_IP_ALIGN;

	}



	if (ieee80211_has_a4(hdr->frame_control))

		padding ^= NET_IP_ALIGN;



	return padding;

}



#define __RADIO_TAP_SIZE_RSV	32



static void _rtl_rx_completed(struct urb *_urb)
@@ -582,9 +613,11 @@ static void _rtl_rx_completed(struct urb *_urb) 
		goto free;



	if (likely(0 == _urb->status)) {

		unsigned int padding;

		struct sk_buff *skb;

		unsigned int qlen;

		unsigned int size = _urb->actual_length;

		struct ieee80211_hdr *hdr;



		if (size < RTL_RX_DESC_SIZE + sizeof(struct ieee80211_hdr)) {

			RT_TRACE(rtlpriv, COMP_USB, DBG_EMERG,
@@ -601,7 +634,10 @@ static void _rtl_rx_completed(struct urb *_urb) 
			goto resubmit;

		}



		skb = dev_alloc_skb(size + __RADIO_TAP_SIZE_RSV);

		hdr = (void *)(_urb->transfer_buffer + RTL_RX_DESC_SIZE);

		padding = _rtl_rx_get_padding(hdr, size - RTL_RX_DESC_SIZE);



		skb = dev_alloc_skb(size + __RADIO_TAP_SIZE_RSV + padding);

		if (!skb) {

			RT_TRACE(rtlpriv, COMP_USB, DBG_EMERG,

				 "Can't allocate skb for bulk IN!\n");
@@ -610,6 +646,9 @@ static void _rtl_rx_completed(struct urb *_urb) 


		_rtl_install_trx_info(rtlusb, skb, rtlusb->in_ep);



		/* Make sure the payload data is 4 byte aligned. */

		skb_reserve(skb, padding);



		/* reserve some space for mac80211's radiotap */

		skb_reserve(skb, __RADIO_TAP_SIZE_RSV);