6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jian Shen shenjian15@huawei.com
[ Upstream commit 61a1deacc3d4fd3d57d7fda4d935f7f7503e8440 ]
Currently, the driver knocks the ring doorbell before updating the ring->last_to_use in tx flow. if the hardware transmiting packet and napi poll scheduling are fast enough, it may get the old ring->last_to_use in drivers' napi poll. In this case, the driver will think the tx is not completed, and return directly without clear the flag __QUEUE_STATE_STACK_XOFF, which may cause tx timeout.
Fixes: 20d06ca2679c ("net: hns3: optimize the tx clean process") Signed-off-by: Jian Shen shenjian15@huawei.com Signed-off-by: Jijie Shao shaojijie@huawei.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index 61f833d61f583..9942b21cd6193 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -2102,8 +2102,12 @@ static void hns3_tx_doorbell(struct hns3_enet_ring *ring, int num, */ if (test_bit(HNS3_NIC_STATE_TX_PUSH_ENABLE, &priv->state) && num && !ring->pending_buf && num <= HNS3_MAX_PUSH_BD_NUM && doorbell) { + /* This smp_store_release() pairs with smp_load_aquire() in + * hns3_nic_reclaim_desc(). Ensure that the BD valid bit + * is updated. + */ + smp_store_release(&ring->last_to_use, ring->next_to_use); hns3_tx_push_bd(ring, num); - WRITE_ONCE(ring->last_to_use, ring->next_to_use); return; }
@@ -2114,6 +2118,11 @@ static void hns3_tx_doorbell(struct hns3_enet_ring *ring, int num, return; }
+ /* This smp_store_release() pairs with smp_load_aquire() in + * hns3_nic_reclaim_desc(). Ensure that the BD valid bit is updated. + */ + smp_store_release(&ring->last_to_use, ring->next_to_use); + if (ring->tqp->mem_base) hns3_tx_mem_doorbell(ring); else @@ -2121,7 +2130,6 @@ static void hns3_tx_doorbell(struct hns3_enet_ring *ring, int num, ring->tqp->io_base + HNS3_RING_TX_RING_TAIL_REG);
ring->pending_buf = 0; - WRITE_ONCE(ring->last_to_use, ring->next_to_use); }
static void hns3_tsyn(struct net_device *netdev, struct sk_buff *skb, @@ -3562,9 +3570,8 @@ static void hns3_reuse_buffer(struct hns3_enet_ring *ring, int i) static bool hns3_nic_reclaim_desc(struct hns3_enet_ring *ring, int *bytes, int *pkts, int budget) { - /* pair with ring->last_to_use update in hns3_tx_doorbell(), - * smp_store_release() is not used in hns3_tx_doorbell() because - * the doorbell operation already have the needed barrier operation. + /* This smp_load_acquire() pairs with smp_store_release() in + * hns3_tx_doorbell(). */ int ltu = smp_load_acquire(&ring->last_to_use); int ntc = ring->next_to_clean;