From: Akihiko Odaki akihiko.odaki@daynix.com
[ Upstream commit eed913f6919e253f35d454b2f115f2a4db2b741a ]
e1000_xmit_frame is expected to stop the queue and dispatch frames to hardware if there is not sufficient space for the next frame in the buffer, but sometimes it failed to do so because the estimated maximum size of frame was wrong. As the consequence, the later invocation of e1000_xmit_frame failed with NETDEV_TX_BUSY, and the frame in the buffer remained forever, resulting in a watchdog failure.
This change fixes the estimated size by making it match with the condition for NETDEV_TX_BUSY. Apparently, the old estimation failed to account for the following lines which determines the space requirement for not causing NETDEV_TX_BUSY: ``` /* reserve a descriptor for the offload context */ if ((mss) || (skb->ip_summed == CHECKSUM_PARTIAL)) count++; count++;
count += DIV_ROUND_UP(len, adapter->tx_fifo_limit); ```
This issue was found when running http-stress02 test included in Linux Test Project 20220930 on QEMU with the following commandline: ``` qemu-system-x86_64 -M q35,accel=kvm -m 8G -smp 8 -drive if=virtio,format=raw,file=root.img,file.locking=on -device e1000e,netdev=netdev -netdev tap,script=ifup,downscript=no,id=netdev ```
Fixes: bc7f75fa9788 ("[E1000E]: New pci-express e1000 driver (currently for ICH9 devices only)") Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com Tested-by: Gurucharan G gurucharanx.g@intel.com (A Contingent worker at Intel) Tested-by: Naama Meir naamax.meir@linux.intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 407bbb4cc236..7e41ce188cc6 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -5941,9 +5941,9 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb, e1000_tx_queue(tx_ring, tx_flags, count); /* Make sure there is space in the ring for the next send. */ e1000_maybe_stop_tx(tx_ring, - (MAX_SKB_FRAGS * + ((MAX_SKB_FRAGS + 1) * DIV_ROUND_UP(PAGE_SIZE, - adapter->tx_fifo_limit) + 2)); + adapter->tx_fifo_limit) + 4));
if (!netdev_xmit_more() || netif_xmit_stopped(netdev_get_tx_queue(netdev, 0))) {