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Commit 872de8ff authored by Jussi Kivilinna's avatar Jussi Kivilinna Committed by John W. Linville
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rtlwifi: usb: use usb_alloc_coherent for RX buffers 



Use dedicated DMA coherent buffers for RX urbs, to avoid allocation of large
skbuffs in hard-irq context and improve performance.

Signed-off-by: default avatarJussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 2ed79f38

drivers/net/wireless/rtlwifi/usb.c

+67 −47
Original line number Diff line number Diff line
@@ -324,6 +324,7 @@ static int _rtl_usb_init_rx(struct ieee80211_hw *hw) 
	pr_info("rx_max_size %d, rx_urb_num %d, in_ep %d\n",

		rtlusb->rx_max_size, rtlusb->rx_urb_num, rtlusb->in_ep);

	init_usb_anchor(&rtlusb->rx_submitted);

	init_usb_anchor(&rtlusb->rx_cleanup_urbs);

	return 0;

}
@@ -405,40 +406,30 @@ static void rtl_usb_init_sw(struct ieee80211_hw *hw) 
	rtlusb->disableHWSM =  true;

}



#define __RADIO_TAP_SIZE_RSV	32



static void _rtl_rx_completed(struct urb *urb);



static struct sk_buff *_rtl_prep_rx_urb(struct ieee80211_hw *hw,

					struct rtl_usb *rtlusb,

					struct urb *urb,

					gfp_t gfp_mask)

static int _rtl_prep_rx_urb(struct ieee80211_hw *hw, struct rtl_usb *rtlusb,

			      struct urb *urb, gfp_t gfp_mask)

{

	struct sk_buff *skb;

	struct rtl_priv *rtlpriv = rtl_priv(hw);

	void *buf;



	skb = __dev_alloc_skb((rtlusb->rx_max_size + __RADIO_TAP_SIZE_RSV),

			       gfp_mask);

	if (!skb) {

	buf = usb_alloc_coherent(rtlusb->udev, rtlusb->rx_max_size, gfp_mask,

				 &urb->transfer_dma);

	if (!buf) {

		RT_TRACE(rtlpriv, COMP_USB, DBG_EMERG,

			 "Failed to __dev_alloc_skb!!\n");

		return ERR_PTR(-ENOMEM);

			 "Failed to usb_alloc_coherent!!\n");

		return -ENOMEM;

	}



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

	skb_reserve(skb, __RADIO_TAP_SIZE_RSV);

	usb_fill_bulk_urb(urb, rtlusb->udev,

			  usb_rcvbulkpipe(rtlusb->udev, rtlusb->in_ep),

			  skb->data, min(skb_tailroom(skb),

			  (int)rtlusb->rx_max_size),

			  _rtl_rx_completed, skb);

			  buf, rtlusb->rx_max_size, _rtl_rx_completed, rtlusb);

	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;



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

	return skb;

	return 0;

}



#undef __RADIO_TAP_SIZE_RSV



static void _rtl_usb_rx_process_agg(struct ieee80211_hw *hw,

				    struct sk_buff *skb)

{
@@ -558,11 +549,11 @@ static void _rtl_rx_pre_process(struct ieee80211_hw *hw, struct sk_buff *skb) 
	}

}



#define __RADIO_TAP_SIZE_RSV	32



static void _rtl_rx_completed(struct urb *_urb)

{

	struct sk_buff *skb = (struct sk_buff *)_urb->context;

	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

	struct rtl_usb *rtlusb = (struct rtl_usb *)info->rate_driver_data[0];

	struct rtl_usb *rtlusb = (struct rtl_usb *)_urb->context;

	struct ieee80211_hw *hw = usb_get_intfdata(rtlusb->intf);

	struct rtl_priv *rtlpriv = rtl_priv(hw);

	int err = 0;
@@ -571,28 +562,42 @@ static void _rtl_rx_completed(struct urb *_urb) 
		goto free;



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

		/* If this code were moved to work queue, would CPU

		 * utilization be improved?  NOTE: We shall allocate another skb

		 * and reuse the original one.

		 */

		skb_put(skb, _urb->actual_length);

		struct sk_buff *skb;

		unsigned int size = _urb->actual_length;



		if (likely(!rtlusb->usb_rx_segregate_hdl)) {

			struct sk_buff *_skb;

			_rtl_usb_rx_process_noagg(hw, skb);

			_skb = _rtl_prep_rx_urb(hw, rtlusb, _urb, GFP_ATOMIC);

			if (IS_ERR(_skb)) {

				err = PTR_ERR(_skb);

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

			RT_TRACE(rtlpriv, COMP_USB, DBG_EMERG,

				 "Too short packet from bulk IN! (len: %d)\n",

				 size);

			goto resubmit;

		}



		skb = dev_alloc_skb(size + __RADIO_TAP_SIZE_RSV);

		if (!skb) {

			RT_TRACE(rtlpriv, COMP_USB, DBG_EMERG,

				 "Can't allocate skb for bulk IN!\n");

				return;

			goto resubmit;

		}

			skb = _skb;



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



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

		skb_reserve(skb, __RADIO_TAP_SIZE_RSV);



		memcpy(skb_put(skb, size), _urb->transfer_buffer, size);



		/* TODO: Do further processing in tasklet (queue skbs,

		 * schedule tasklet)

		 */



		if (likely(!rtlusb->usb_rx_segregate_hdl)) {

			_rtl_usb_rx_process_noagg(hw, skb);

		} else {

			/* TO DO */

			_rtl_rx_pre_process(hw, skb);

			pr_err("rx agg not supported\n");

		}



		goto resubmit;

	}
@@ -608,9 +613,6 @@ static void _rtl_rx_completed(struct urb *_urb) 
	}



resubmit:

	skb_reset_tail_pointer(skb);

	skb_trim(skb, 0);



	usb_anchor_urb(_urb, &rtlusb->rx_submitted);

	err = usb_submit_urb(_urb, GFP_ATOMIC);

	if (unlikely(err)) {
@@ -620,13 +622,31 @@ static void _rtl_rx_completed(struct urb *_urb) 
	return;



free:

	dev_kfree_skb_irq(skb);

	/* On some architectures, usb_free_coherent must not be called from

	 * hardirq context. Queue urb to cleanup list.

	 */

	usb_anchor_urb(_urb, &rtlusb->rx_cleanup_urbs);

}



#undef __RADIO_TAP_SIZE_RSV



static void _rtl_usb_cleanup_rx(struct ieee80211_hw *hw)

{

	struct rtl_usb *rtlusb = rtl_usbdev(rtl_usbpriv(hw));

	struct urb *urb;



	usb_kill_anchored_urbs(&rtlusb->rx_submitted);



	while ((urb = usb_get_from_anchor(&rtlusb->rx_cleanup_urbs))) {

		usb_free_coherent(urb->dev, urb->transfer_buffer_length,

				urb->transfer_buffer, urb->transfer_dma);

		usb_free_urb(urb);

	}

}



static int _rtl_usb_receive(struct ieee80211_hw *hw)

{

	struct urb *urb;

	struct sk_buff *skb;

	int err;

	int i;

	struct rtl_priv *rtlpriv = rtl_priv(hw);
@@ -645,11 +665,10 @@ static int _rtl_usb_receive(struct ieee80211_hw *hw) 
			goto err_out;

		}



		skb = _rtl_prep_rx_urb(hw, rtlusb, urb, GFP_KERNEL);

		if (IS_ERR(skb)) {

		err = _rtl_prep_rx_urb(hw, rtlusb, urb, GFP_KERNEL);

		if (err < 0) {

			RT_TRACE(rtlpriv, COMP_USB, DBG_EMERG,

				 "Failed to prep_rx_urb!!\n");

			err = PTR_ERR(skb);

			usb_free_urb(urb);

			goto err_out;

		}
@@ -664,6 +683,7 @@ static int _rtl_usb_receive(struct ieee80211_hw *hw) 


err_out:

	usb_kill_anchored_urbs(&rtlusb->rx_submitted);

	_rtl_usb_cleanup_rx(hw);

	return err;

}
@@ -705,7 +725,7 @@ static void rtl_usb_cleanup(struct ieee80211_hw *hw) 
	SET_USB_STOP(rtlusb);



	/* clean up rx stuff. */

	usb_kill_anchored_urbs(&rtlusb->rx_submitted);

	_rtl_usb_cleanup_rx(hw);



	/* clean up tx stuff */

	for (i = 0; i < RTL_USB_MAX_EP_NUM; i++) {

drivers/net/wireless/rtlwifi/usb.h

+1 −0
Original line number Diff line number Diff line
@@ -141,6 +141,7 @@ struct rtl_usb { 
	u32 rx_max_size;	/* Bulk IN max buffer size */

	u32 rx_urb_num;		/* How many Bulk INs are submitted to host. */

	struct usb_anchor	rx_submitted;

	struct usb_anchor	rx_cleanup_urbs;

	void (*usb_rx_segregate_hdl)(struct ieee80211_hw *, struct sk_buff *,

				     struct sk_buff_head *);

	void (*usb_rx_hdl)(struct ieee80211_hw *, struct sk_buff *);