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: 6d6b39f180b8 ("net: fec: add initial XDP support")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 9939ccafb556..8c0226d061fe 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -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;