From: Jakub Kicinski kuba@kernel.org
[ Upstream commit e8d8c5d80f5e9d4586c68061b62c642752289095 ]
skbs are freed on error and not put on the ring. We may, however, be in a situation where we're freeing the last skb of a batch, and there is a doorbell ring pending because of xmit_more() being true earlier. Make sure we ring the door bell in such situations.
Since errors are rare don't pay attention to xmit_more() and just always flush the pending frames.
The busy case should be safe to be left alone because it can only happen if start_xmit races with completions and they both enable the queue. In that case the kick can't be pending.
Noticed while reading the code.
Fixes: 4d172f21cefe ("bnxt_en: Implement xmit_more.") Reviewed-by: Michael Chan michael.chan@broadcom.com Reviewed-by: Edwin Peer edwin.peer@broadcom.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 39 +++++++++++++++-------- drivers/net/ethernet/broadcom/bnxt/bnxt.h | 1 + 2 files changed, 27 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 621346656af3..dd03e1e6279a 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -69,7 +69,8 @@ #include "bnxt_debugfs.h"
#define BNXT_TX_TIMEOUT (5 * HZ) -#define BNXT_DEF_MSG_ENABLE (NETIF_MSG_DRV | NETIF_MSG_HW) +#define BNXT_DEF_MSG_ENABLE (NETIF_MSG_DRV | NETIF_MSG_HW | \ + NETIF_MSG_TX_ERR)
MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Broadcom BCM573xx network driver"); @@ -360,6 +361,13 @@ static u16 bnxt_xmit_get_cfa_action(struct sk_buff *skb) return md_dst->u.port_info.port_id; }
+static void bnxt_txr_db_kick(struct bnxt *bp, struct bnxt_tx_ring_info *txr, + u16 prod) +{ + bnxt_db_write(bp, &txr->tx_db, prod); + txr->kick_pending = 0; +} + static bool bnxt_txr_netif_try_stop_queue(struct bnxt *bp, struct bnxt_tx_ring_info *txr, struct netdev_queue *txq) @@ -407,6 +415,10 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
free_size = bnxt_tx_avail(bp, txr); if (unlikely(free_size < skb_shinfo(skb)->nr_frags + 2)) { + /* We must have raced with NAPI cleanup */ + if (net_ratelimit() && txr->kick_pending) + netif_warn(bp, tx_err, dev, + "bnxt: ring busy w/ flush pending!\n"); if (bnxt_txr_netif_try_stop_queue(bp, txr, txq)) return NETDEV_TX_BUSY; } @@ -510,21 +522,16 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) normal_tx: if (length < BNXT_MIN_PKT_SIZE) { pad = BNXT_MIN_PKT_SIZE - length; - if (skb_pad(skb, pad)) { + if (skb_pad(skb, pad)) /* SKB already freed. */ - tx_buf->skb = NULL; - return NETDEV_TX_OK; - } + goto tx_kick_pending; length = BNXT_MIN_PKT_SIZE; }
mapping = dma_map_single(&pdev->dev, skb->data, len, DMA_TO_DEVICE);
- if (unlikely(dma_mapping_error(&pdev->dev, mapping))) { - dev_kfree_skb_any(skb); - tx_buf->skb = NULL; - return NETDEV_TX_OK; - } + if (unlikely(dma_mapping_error(&pdev->dev, mapping))) + goto tx_free;
dma_unmap_addr_set(tx_buf, mapping, mapping); flags = (len << TX_BD_LEN_SHIFT) | TX_BD_TYPE_LONG_TX_BD | @@ -609,13 +616,15 @@ normal_tx: txr->tx_prod = prod;
if (!netdev_xmit_more() || netif_xmit_stopped(txq)) - bnxt_db_write(bp, &txr->tx_db, prod); + bnxt_txr_db_kick(bp, txr, prod); + else + txr->kick_pending = 1;
tx_done:
if (unlikely(bnxt_tx_avail(bp, txr) <= MAX_SKB_FRAGS + 1)) { if (netdev_xmit_more() && !tx_buf->is_push) - bnxt_db_write(bp, &txr->tx_db, prod); + bnxt_txr_db_kick(bp, txr, prod);
bnxt_txr_netif_try_stop_queue(bp, txr, txq); } @@ -627,7 +636,6 @@ tx_dma_error: /* start back at beginning and unmap skb */ prod = txr->tx_prod; tx_buf = &txr->tx_buf_ring[prod]; - tx_buf->skb = NULL; dma_unmap_single(&pdev->dev, dma_unmap_addr(tx_buf, mapping), skb_headlen(skb), PCI_DMA_TODEVICE); prod = NEXT_TX(prod); @@ -641,7 +649,12 @@ tx_dma_error: PCI_DMA_TODEVICE); }
+tx_free: dev_kfree_skb_any(skb); +tx_kick_pending: + if (txr->kick_pending) + bnxt_txr_db_kick(bp, txr, txr->tx_prod); + txr->tx_buf_ring[txr->tx_prod].skb = NULL; return NETDEV_TX_OK; }
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h index a95c5afa2f01..95d10e7bbb04 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h @@ -770,6 +770,7 @@ struct bnxt_tx_ring_info { u16 tx_prod; u16 tx_cons; u16 txq_index; + u8 kick_pending; struct bnxt_db_info tx_db;
struct tx_bd *tx_desc_ring[MAX_TX_PAGES];