Commit 20f79739 authored by Wei Fang's avatar Wei Fang Committed by Paolo Abeni
Browse files

net: fec: recycle pages for transmitted XDP frames 



Once the XDP frames have been successfully transmitted through the
ndo_xdp_xmit() interface, it's the driver responsibility to free
the frames so that the page_pool can recycle the pages and reuse
them. However, this action is not implemented in the fec driver.
This leads to a user-visible problem that the console will print
the following warning log.

[  157.568851] page_pool_release_retry() stalled pool shutdown 1389 inflight 60 sec
[  217.983446] page_pool_release_retry() stalled pool shutdown 1389 inflight 120 sec
[  278.399006] page_pool_release_retry() stalled pool shutdown 1389 inflight 181 sec
[  338.812885] page_pool_release_retry() stalled pool shutdown 1389 inflight 241 sec
[  399.226946] page_pool_release_retry() stalled pool shutdown 1389 inflight 302 sec

Therefore, to solve this issue, we free XDP frames via xdp_return_frame()
while cleaning the tx BD ring.

Fixes: 6d6b39f1 ("net: fec: add initial XDP support")
Signed-off-by: default avatarWei Fang <wei.fang@nxp.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent be7ecbe7

drivers/net/ethernet/freescale/fec.h

+14 −1
Original line number Diff line number Diff line
@@ -544,10 +544,23 @@ enum { 
	XDP_STATS_TOTAL,

};



enum fec_txbuf_type {

	FEC_TXBUF_T_SKB,

	FEC_TXBUF_T_XDP_NDO,

};



struct fec_tx_buffer {

	union {

		struct sk_buff *skb;

		struct xdp_frame *xdp;

	};

	enum fec_txbuf_type type;

};



struct fec_enet_priv_tx_q {

	struct bufdesc_prop bd;

	unsigned char *tx_bounce[TX_RING_SIZE];

	struct  sk_buff *tx_skbuff[TX_RING_SIZE];

	struct fec_tx_buffer tx_buf[TX_RING_SIZE];



	unsigned short tx_stop_threshold;

	unsigned short tx_wake_threshold;

drivers/net/ethernet/freescale/fec_main.c

+101 −47
Original line number Diff line number Diff line
@@ -397,7 +397,7 @@ static void fec_dump(struct net_device *ndev) 
			fec16_to_cpu(bdp->cbd_sc),

			fec32_to_cpu(bdp->cbd_bufaddr),

			fec16_to_cpu(bdp->cbd_datlen),

			txq->tx_skbuff[index]);

			txq->tx_buf[index].skb);

		bdp = fec_enet_get_nextdesc(bdp, &txq->bd);

		index++;

	} while (bdp != txq->bd.base);
@@ -654,7 +654,7 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq, 


	index = fec_enet_get_bd_index(last_bdp, &txq->bd);

	/* Save skb pointer */

	txq->tx_skbuff[index] = skb;

	txq->tx_buf[index].skb = skb;



	/* Make sure the updates to rest of the descriptor are performed before

	 * transferring ownership.
@@ -672,9 +672,7 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq, 


	skb_tx_timestamp(skb);



	/* Make sure the update to bdp and tx_skbuff are performed before

	 * txq->bd.cur.

	 */

	/* Make sure the update to bdp is performed before txq->bd.cur. */

	wmb();

	txq->bd.cur = bdp;
@@ -862,7 +860,7 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq, 
	}



	/* Save skb pointer */

	txq->tx_skbuff[index] = skb;

	txq->tx_buf[index].skb = skb;



	skb_tx_timestamp(skb);

	txq->bd.cur = bdp;
@@ -952,16 +950,33 @@ static void fec_enet_bd_init(struct net_device *dev) 
		for (i = 0; i < txq->bd.ring_size; i++) {

			/* Initialize the BD for every fragment in the page. */

			bdp->cbd_sc = cpu_to_fec16(0);

			if (txq->tx_buf[i].type == FEC_TXBUF_T_SKB) {

				if (bdp->cbd_bufaddr &&

				    !IS_TSO_HEADER(txq, fec32_to_cpu(bdp->cbd_bufaddr)))

					dma_unmap_single(&fep->pdev->dev,

							 fec32_to_cpu(bdp->cbd_bufaddr),

							 fec16_to_cpu(bdp->cbd_datlen),

							 DMA_TO_DEVICE);

			if (txq->tx_skbuff[i]) {

				dev_kfree_skb_any(txq->tx_skbuff[i]);

				txq->tx_skbuff[i] = NULL;

				if (txq->tx_buf[i].skb) {

					dev_kfree_skb_any(txq->tx_buf[i].skb);

					txq->tx_buf[i].skb = NULL;

				}

			} else {

				if (bdp->cbd_bufaddr)

					dma_unmap_single(&fep->pdev->dev,

							 fec32_to_cpu(bdp->cbd_bufaddr),

							 fec16_to_cpu(bdp->cbd_datlen),

							 DMA_TO_DEVICE);



				if (txq->tx_buf[i].xdp) {

					xdp_return_frame(txq->tx_buf[i].xdp);

					txq->tx_buf[i].xdp = NULL;

				}



				/* restore default tx buffer type: FEC_TXBUF_T_SKB */

				txq->tx_buf[i].type = FEC_TXBUF_T_SKB;

			}



			bdp->cbd_bufaddr = cpu_to_fec32(0);

			bdp = fec_enet_get_nextdesc(bdp, &txq->bd);

		}
@@ -1360,6 +1375,7 @@ static void 
fec_enet_tx_queue(struct net_device *ndev, u16 queue_id)

{

	struct	fec_enet_private *fep;

	struct xdp_frame *xdpf;

	struct bufdesc *bdp;

	unsigned short status;

	struct	sk_buff	*skb;
@@ -1387,16 +1403,31 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id) 


		index = fec_enet_get_bd_index(bdp, &txq->bd);



		skb = txq->tx_skbuff[index];

		txq->tx_skbuff[index] = NULL;

		if (!IS_TSO_HEADER(txq, fec32_to_cpu(bdp->cbd_bufaddr)))

		if (txq->tx_buf[index].type == FEC_TXBUF_T_SKB) {

			skb = txq->tx_buf[index].skb;

			txq->tx_buf[index].skb = NULL;

			if (bdp->cbd_bufaddr &&

			    !IS_TSO_HEADER(txq, fec32_to_cpu(bdp->cbd_bufaddr)))

				dma_unmap_single(&fep->pdev->dev,

						 fec32_to_cpu(bdp->cbd_bufaddr),

						 fec16_to_cpu(bdp->cbd_datlen),

						 DMA_TO_DEVICE);

			bdp->cbd_bufaddr = cpu_to_fec32(0);

			if (!skb)

			goto skb_done;

				goto tx_buf_done;

		} else {

			xdpf = txq->tx_buf[index].xdp;

			if (bdp->cbd_bufaddr)

				dma_unmap_single(&fep->pdev->dev,

						 fec32_to_cpu(bdp->cbd_bufaddr),

						 fec16_to_cpu(bdp->cbd_datlen),

						 DMA_TO_DEVICE);

			bdp->cbd_bufaddr = cpu_to_fec32(0);

			if (!xdpf) {

				txq->tx_buf[index].type = FEC_TXBUF_T_SKB;

				goto tx_buf_done;

			}

		}



		/* Check for errors. */

		if (status & (BD_ENET_TX_HB | BD_ENET_TX_LC |
@@ -1415,16 +1446,26 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id) 
				ndev->stats.tx_carrier_errors++;

		} else {

			ndev->stats.tx_packets++;



			if (txq->tx_buf[index].type == FEC_TXBUF_T_SKB)

				ndev->stats.tx_bytes += skb->len;

			else

				ndev->stats.tx_bytes += xdpf->len;

		}



		/* Deferred means some collisions occurred during transmit,

		 * but we eventually sent the packet OK.

		 */

		if (status & BD_ENET_TX_DEF)

			ndev->stats.collisions++;



		if (txq->tx_buf[index].type == FEC_TXBUF_T_SKB) {

			/* NOTE: SKBTX_IN_PROGRESS being set does not imply it's we who

			 * are to time stamp the packet, so we still need to check time

			 * stamping enabled flag.

			 */

			if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS &&

			     fep->hwts_tx_en) &&

		    fep->bufdesc_ex) {

				     fep->hwts_tx_en) && fep->bufdesc_ex) {

				struct skb_shared_hwtstamps shhwtstamps;

				struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
@@ -1432,16 +1473,18 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id) 
				skb_tstamp_tx(skb, &shhwtstamps);

			}



		/* Deferred means some collisions occurred during transmit,

		 * but we eventually sent the packet OK.

		 */

		if (status & BD_ENET_TX_DEF)

			ndev->stats.collisions++;



			/* Free the sk buffer associated with this last transmit */

			dev_kfree_skb_any(skb);

skb_done:

		/* Make sure the update to bdp and tx_skbuff are performed

		} else {

			xdp_return_frame(xdpf);



			txq->tx_buf[index].xdp = NULL;

			/* restore default tx buffer type: FEC_TXBUF_T_SKB */

			txq->tx_buf[index].type = FEC_TXBUF_T_SKB;

		}



tx_buf_done:

		/* Make sure the update to bdp and tx_buf are performed

		 * before dirty_tx

		 */

		wmb();
@@ -3249,9 +3292,19 @@ static void fec_enet_free_buffers(struct net_device *ndev) 
		for (i = 0; i < txq->bd.ring_size; i++) {

			kfree(txq->tx_bounce[i]);

			txq->tx_bounce[i] = NULL;

			skb = txq->tx_skbuff[i];

			txq->tx_skbuff[i] = NULL;



			if (txq->tx_buf[i].type == FEC_TXBUF_T_SKB) {

				skb = txq->tx_buf[i].skb;

				txq->tx_buf[i].skb = NULL;

				dev_kfree_skb(skb);

			} else {

				if (txq->tx_buf[i].xdp) {

					xdp_return_frame(txq->tx_buf[i].xdp);

					txq->tx_buf[i].xdp = NULL;

				}



				txq->tx_buf[i].type = FEC_TXBUF_T_SKB;

			}

		}

	}

}
@@ -3817,7 +3870,8 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep, 
		ebdp->cbd_esc = cpu_to_fec32(estatus);

	}



	txq->tx_skbuff[index] = NULL;

	txq->tx_buf[index].type = FEC_TXBUF_T_XDP_NDO;

	txq->tx_buf[index].xdp = frame;



	/* Make sure the updates to rest of the descriptor are performed before

	 * transferring ownership.