From: Robert Hancock robert.hancock@calian.com
[ Upstream commit 7a7d340ba4d9351e4c8847b898a2b996727a922a ]
If a memory allocation error occurred during an attempt to refill a slot in the RX ring after the packet was received, the hardware tail pointer would still have been updated to point to or past the slot which remained marked as previously completed. This would likely result in the DMA engine raising an error when it eventually tried to use that slot again.
If a slot cannot be refilled, then just stop processing and do not move the tail pointer past it. On the next attempt, we should skip receiving the packet from the empty slot and just try to refill it again.
This failure mode has not actually been observed, but was found as part of other driver updates.
Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock robert.hancock@calian.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- .../net/ethernet/xilinx/xilinx_axienet_main.c | 72 +++++++++++-------- 1 file changed, 42 insertions(+), 30 deletions(-)
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 2169417210c2..80637ffcca93 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -857,46 +857,53 @@ static void axienet_recv(struct net_device *ndev) while ((cur_p->status & XAXIDMA_BD_STS_COMPLETE_MASK)) { dma_addr_t phys;
- tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci; - /* Ensure we see complete descriptor update */ dma_rmb(); - phys = desc_get_phys_addr(lp, cur_p); - dma_unmap_single(ndev->dev.parent, phys, lp->max_frm_size, - DMA_FROM_DEVICE);
skb = cur_p->skb; cur_p->skb = NULL; - length = cur_p->app4 & 0x0000FFFF; - - skb_put(skb, length); - skb->protocol = eth_type_trans(skb, ndev); - /*skb_checksum_none_assert(skb);*/ - skb->ip_summed = CHECKSUM_NONE; - - /* if we're doing Rx csum offload, set it up */ - if (lp->features & XAE_FEATURE_FULL_RX_CSUM) { - csumstatus = (cur_p->app2 & - XAE_FULL_CSUM_STATUS_MASK) >> 3; - if ((csumstatus == XAE_IP_TCP_CSUM_VALIDATED) || - (csumstatus == XAE_IP_UDP_CSUM_VALIDATED)) { - skb->ip_summed = CHECKSUM_UNNECESSARY; + + /* skb could be NULL if a previous pass already received the + * packet for this slot in the ring, but failed to refill it + * with a newly allocated buffer. In this case, don't try to + * receive it again. + */ + if (likely(skb)) { + length = cur_p->app4 & 0x0000FFFF; + + phys = desc_get_phys_addr(lp, cur_p); + dma_unmap_single(ndev->dev.parent, phys, lp->max_frm_size, + DMA_FROM_DEVICE); + + skb_put(skb, length); + skb->protocol = eth_type_trans(skb, ndev); + /*skb_checksum_none_assert(skb);*/ + skb->ip_summed = CHECKSUM_NONE; + + /* if we're doing Rx csum offload, set it up */ + if (lp->features & XAE_FEATURE_FULL_RX_CSUM) { + csumstatus = (cur_p->app2 & + XAE_FULL_CSUM_STATUS_MASK) >> 3; + if (csumstatus == XAE_IP_TCP_CSUM_VALIDATED || + csumstatus == XAE_IP_UDP_CSUM_VALIDATED) { + skb->ip_summed = CHECKSUM_UNNECESSARY; + } + } else if ((lp->features & XAE_FEATURE_PARTIAL_RX_CSUM) != 0 && + skb->protocol == htons(ETH_P_IP) && + skb->len > 64) { + skb->csum = be32_to_cpu(cur_p->app3 & 0xFFFF); + skb->ip_summed = CHECKSUM_COMPLETE; } - } else if ((lp->features & XAE_FEATURE_PARTIAL_RX_CSUM) != 0 && - skb->protocol == htons(ETH_P_IP) && - skb->len > 64) { - skb->csum = be32_to_cpu(cur_p->app3 & 0xFFFF); - skb->ip_summed = CHECKSUM_COMPLETE; - }
- netif_rx(skb); + netif_rx(skb);
- size += length; - packets++; + size += length; + packets++; + }
new_skb = netdev_alloc_skb_ip_align(ndev, lp->max_frm_size); if (!new_skb) - return; + break;
phys = dma_map_single(ndev->dev.parent, new_skb->data, lp->max_frm_size, @@ -905,7 +912,7 @@ static void axienet_recv(struct net_device *ndev) if (net_ratelimit()) netdev_err(ndev, "RX DMA mapping error\n"); dev_kfree_skb(new_skb); - return; + break; } desc_set_phys_addr(lp, phys, cur_p);
@@ -913,6 +920,11 @@ static void axienet_recv(struct net_device *ndev) cur_p->status = 0; cur_p->skb = new_skb;
+ /* Only update tail_p to mark this slot as usable after it has + * been successfully refilled. + */ + tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci; + if (++lp->rx_bd_ci >= lp->rx_bd_num) lp->rx_bd_ci = 0; cur_p = &lp->rx_bd_v[lp->rx_bd_ci];