From 82172b765530f84b4b9da929f2dcf46f2b7b232b Mon Sep 17 00:00:00 2001 From: Mike Marciniszyn Date: Tue, 23 Jun 2020 16:43:22 -0400 Subject: [PATCH] IB/hfi1: Correct -EBUSY handling in tx code The current code mishandles -EBUSY in two ways: - The flow change doesn't test the return from the flush and runs on to process the current packet racing with the wakeup processing - The -EBUSY handling for a single packet inserts the tx into the txlist after the submit call, racing with the same wakeup processing Fix the first by dropping the skb and returning NETDEV_TX_OK. Fix the second by insuring the the list entry within the txreq is inited when allocated. This enables the sleep routine to detect that the txreq has used the non-list api and queue the packet to the txlist. Both flaws can lead to having the flushing thread executing in causing two threads to manipulate the txlist. Fixes: d99dc602e2a5 ("IB/hfi1: Add functions to transmit datagram ipoib packets") Link: https://lore.kernel.org/r/20200623204321.108092.83898.stgit@awfm-01.aw.intel.com Reviewed-by: Kaike Wan Signed-off-by: Mike Marciniszyn Signed-off-by: Dennis Dalessandro Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/hfi1/ipoib_tx.c | 35 ++++++++++++++------------- 1 file changed, 18 insertions(+), 17 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/ipoib_tx.c b/drivers/infiniband/hw/hfi1/ipoib_tx.c index 175290c56db9..76dcb5624aa6 100644 --- a/drivers/infiniband/hw/hfi1/ipoib_tx.c +++ b/drivers/infiniband/hw/hfi1/ipoib_tx.c @@ -369,6 +369,7 @@ static struct ipoib_txreq *hfi1_ipoib_send_dma_common(struct net_device *dev, tx->priv = priv; tx->txq = txp->txq; tx->skb = skb; + INIT_LIST_HEAD(&tx->txreq.list); hfi1_ipoib_build_ib_tx_headers(tx, txp); @@ -469,6 +470,7 @@ static int hfi1_ipoib_send_dma_single(struct net_device *dev, ret = hfi1_ipoib_submit_tx(txq, tx); if (likely(!ret)) { +tx_ok: trace_sdma_output_ibhdr(tx->priv->dd, &tx->sdma_hdr.hdr, ib_is_sc5(txp->flow.sc5)); @@ -478,20 +480,8 @@ static int hfi1_ipoib_send_dma_single(struct net_device *dev, txq->pkts_sent = false; - if (ret == -EBUSY) { - list_add_tail(&tx->txreq.list, &txq->tx_list); - - trace_sdma_output_ibhdr(tx->priv->dd, - &tx->sdma_hdr.hdr, - ib_is_sc5(txp->flow.sc5)); - hfi1_ipoib_check_queue_depth(txq); - return NETDEV_TX_OK; - } - - if (ret == -ECOMM) { - hfi1_ipoib_check_queue_depth(txq); - return NETDEV_TX_OK; - } + if (ret == -EBUSY || ret == -ECOMM) + goto tx_ok; sdma_txclean(priv->dd, &tx->txreq); dev_kfree_skb_any(skb); @@ -509,9 +499,17 @@ static int hfi1_ipoib_send_dma_list(struct net_device *dev, struct ipoib_txreq *tx; /* Has the flow change ? */ - if (txq->flow.as_int != txp->flow.as_int) - (void)hfi1_ipoib_flush_tx_list(dev, txq); - + if (txq->flow.as_int != txp->flow.as_int) { + int ret; + + ret = hfi1_ipoib_flush_tx_list(dev, txq); + if (unlikely(ret)) { + if (ret == -EBUSY) + ++dev->stats.tx_dropped; + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; + } + } tx = hfi1_ipoib_send_dma_common(dev, skb, txp); if (IS_ERR(tx)) { int ret = PTR_ERR(tx); @@ -612,6 +610,9 @@ static int hfi1_ipoib_sdma_sleep(struct sdma_engine *sde, netif_stop_subqueue(txq->priv->netdev, txq->q_idx); + if (list_empty(&txreq->list)) + /* came from non-list submit */ + list_add_tail(&txreq->list, &txq->tx_list); if (list_empty(&txq->wait.list)) iowait_queue(pkts_sent, wait->iow, &sde->dmawait); -- GitLab