net: aquantia: invalid checksumm offload implementation

Packets with marked invalid IP/UDP/TCP checksums were considered as good
by the driver. The error was in a logic, processing offload bits in
RX descriptor.
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: Dmitry Bogdanov <dmitry.bogdanov@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/aq_ring.c

@@ -172,6 +172,27 @@ bool aq_ring_tx_clean(struct aq_ring_s *self)
 	return !!budget;
 }
 
+static void aq_rx_checksum(struct aq_ring_s *self,
+			   struct aq_ring_buff_s *buff,
+			   struct sk_buff *skb)
+{
+	if (!(self->aq_nic->ndev->features & NETIF_F_RXCSUM))
+		return;
+
+	if (unlikely(buff->is_cso_err)) {
+		++self->stats.rx.errors;
+		skb->ip_summed = CHECKSUM_NONE;
+		return;
+	}
+	if (buff->is_ip_cso) {
+		__skb_incr_checksum_unnecessary(skb);
+		if (buff->is_udp_cso || buff->is_tcp_cso)
+			__skb_incr_checksum_unnecessary(skb);
+	} else {
+		skb->ip_summed = CHECKSUM_NONE;
+	}
+}
+
 #define AQ_SKB_ALIGN SKB_DATA_ALIGN(sizeof(struct skb_shared_info))
 int aq_ring_rx_clean(struct aq_ring_s *self,
 		     struct napi_struct *napi,
@@ -267,18 +288,8 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 		}
 
 		skb->protocol = eth_type_trans(skb, ndev);
-		if (unlikely(buff->is_cso_err)) {
-			++self->stats.rx.errors;
-			skb->ip_summed = CHECKSUM_NONE;
-		} else {
-			if (buff->is_ip_cso) {
-				__skb_incr_checksum_unnecessary(skb);
-				if (buff->is_udp_cso || buff->is_tcp_cso)
-					__skb_incr_checksum_unnecessary(skb);
-			} else {
-				skb->ip_summed = CHECKSUM_NONE;
-			}
-		}
+
+		aq_rx_checksum(self, buff, skb);
 
 		skb_set_hash(skb, buff->rss_hash,
 			     buff->is_hash_l4 ? PKT_HASH_TYPE_L4 :

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c

@@ -660,9 +660,9 @@ static int hw_atl_b0_hw_ring_rx_receive(struct aq_hw_s *self,
 		struct hw_atl_rxd_wb_s *rxd_wb = (struct hw_atl_rxd_wb_s *)
 			&ring->dx_ring[ring->hw_head * HW_ATL_B0_RXD_SIZE];
 
-		unsigned int is_err = 1U;
 		unsigned int is_rx_check_sum_enabled = 0U;
 		unsigned int pkt_type = 0U;
+		u8 rx_stat = 0U;
 
 		if (!(rxd_wb->status & 0x1U)) { /* RxD is not done */
 			break;
@@ -670,35 +670,35 @@ static int hw_atl_b0_hw_ring_rx_receive(struct aq_hw_s *self,
 
 		buff = &ring->buff_ring[ring->hw_head];
 
-		is_err = (0x0000003CU & rxd_wb->status);
+		rx_stat = (0x0000003CU & rxd_wb->status) >> 2;
 
 		is_rx_check_sum_enabled = (rxd_wb->type) & (0x3U << 19);
-		is_err &= ~0x20U; /* exclude validity bit */
 
 		pkt_type = 0xFFU & (rxd_wb->type >> 4);
 
-		if (is_rx_check_sum_enabled) {
-			if (0x0U == (pkt_type & 0x3U))
-				buff->is_ip_cso = (is_err & 0x08U) ? 0U : 1U;
+		if (is_rx_check_sum_enabled & BIT(0) &&
+		    (0x0U == (pkt_type & 0x3U)))
+			buff->is_ip_cso = (rx_stat & BIT(1)) ? 0U : 1U;
 
+		if (is_rx_check_sum_enabled & BIT(1)) {
 			if (0x4U == (pkt_type & 0x1CU))
-				buff->is_udp_cso = buff->is_cso_err ? 0U : 1U;
+				buff->is_udp_cso = (rx_stat & BIT(2)) ? 0U :
+						   !!(rx_stat & BIT(3));
 			else if (0x0U == (pkt_type & 0x1CU))
-				buff->is_tcp_cso = buff->is_cso_err ? 0U : 1U;
-
-			/* Checksum offload workaround for small packets */
-			if (rxd_wb->pkt_len <= 60) {
-				buff->is_ip_cso = 0U;
-				buff->is_cso_err = 0U;
-			}
+				buff->is_tcp_cso = (rx_stat & BIT(2)) ? 0U :
+						   !!(rx_stat & BIT(3));
+		}
+		buff->is_cso_err = !!(rx_stat & 0x6);
+		/* Checksum offload workaround for small packets */
+		if (unlikely(rxd_wb->pkt_len <= 60)) {
+			buff->is_ip_cso = 0U;
+			buff->is_cso_err = 0U;
 		}
-
-		is_err &= ~0x18U;
 
 		dma_unmap_page(ndev, buff->pa, buff->len, DMA_FROM_DEVICE);
 
-		if (is_err || rxd_wb->type & 0x1000U) {
-			/* status error or DMA error */
+		if ((rx_stat & BIT(0)) || rxd_wb->type & 0x1000U) {
+			/* MAC error or DMA error */
 			buff->is_error = 1U;
 		} else {
 			if (self->aq_nic_cfg->is_rss) {