net: aquantia: fix LRO with FCS error

This change “net: aquantia: fix LRO with FCS error” (commit eaeb3b7) in Linux kernel is authored by Dmitry Bogdanov <dmitry.bogdanov [at] aquantia.com> on Sat May 25 09:58:03 2019 +0000.

Description of "net: aquantia: fix LRO with FCS error"

The change “net: aquantia: fix LRO with FCS error” introduces changes as follows.

net: aquantia: fix LRO with FCS error

Driver stops producing skbs on ring if a packet with FCS error
was coalesced into LRO session. Ring gets hang forever.

Thats a logical error in driver processing descriptors:
When rx_stat indicates MAC Error, next pointer and eop flags
are not filled. This confuses driver so it waits for descriptor 0
to be filled by HW.

Solution is fill next pointer and eop flag even for packets with FCS error.

Fixes: bab6de8fd180b ("net: ethernet: aquantia: Atlantic A0 and B0 specific functions.")
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>

Linux kernel releases containing commit eaeb3b7

The Linux kernel releases containing this commit are as follows.

Linux kernel code changes from "net: aquantia: fix LRO with FCS error"

There are 61 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 .../aquantia/atlantic/hw_atl/hw_atl_b0.c      | 61 ++++++++++---------
 1 file changed, 32 insertions(+), 29 deletions(-)
 
diff --git a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
index bfcda12d73de..e979f227cf0b 100644
--- a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
+++ b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
@@ -713,38 +713,41 @@ static int hw_atl_b0_hw_ring_rx_receive(struct aq_hw_s *self,
 		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) {
-				/* last 4 byte */
-				u16 rss_type = rxd_wb->type & 0xFU;
-
-				if (rss_type && rss_type < 0x8U) {
-					buff->is_hash_l4 = (rss_type == 0x4 ||
-					rss_type == 0x5);
-					buff->rss_hash = rxd_wb->rss_hash;
-				}
+		}
+		if (self->aq_nic_cfg->is_rss) {
+			/* last 4 byte */
+			u16 rss_type = rxd_wb->type & 0xFU;
+
+			if (rss_type && rss_type < 0x8U) {
+				buff->is_hash_l4 = (rss_type == 0x4 ||
+				rss_type == 0x5);
+				buff->rss_hash = rxd_wb->rss_hash;
 			}
+		}
 
-			if (HW_ATL_B0_RXD_WB_STAT2_EOP & rxd_wb->status) {
-				buff->len = rxd_wb->pkt_len %
-					AQ_CFG_RX_FRAME_MAX;
-				buff->len = buff->len ?
-					buff->len : AQ_CFG_RX_FRAME_MAX;
-				buff->next = 0U;
-				buff->is_eop = 1U;
+		if (HW_ATL_B0_RXD_WB_STAT2_EOP & rxd_wb->status) {
+			buff->len = rxd_wb->pkt_len %
+				AQ_CFG_RX_FRAME_MAX;
+			buff->len = buff->len ?
+				buff->len : AQ_CFG_RX_FRAME_MAX;
+			buff->next = 0U;
+			buff->is_eop = 1U;
+		} else {
+			buff->len =
+				rxd_wb->pkt_len > AQ_CFG_RX_FRAME_MAX ?
+				AQ_CFG_RX_FRAME_MAX : rxd_wb->pkt_len;
+
+			if (HW_ATL_B0_RXD_WB_STAT2_RSCCNT &
+				rxd_wb->status) {
+				/* LRO */
+				buff->next = rxd_wb->next_desc_ptr;
+				++ring->stats.rx.lro_packets;
 			} else {
-				if (HW_ATL_B0_RXD_WB_STAT2_RSCCNT &
-					rxd_wb->status) {
-					/* LRO */
-					buff->next = rxd_wb->next_desc_ptr;
-					++ring->stats.rx.lro_packets;
-				} else {
-					/* jumbo */
-					buff->next =
-						aq_ring_next_dx(ring,
-								ring->hw_head);
-					++ring->stats.rx.jumbo_packets;
-				}
+				/* jumbo */
+				buff->next =
+					aq_ring_next_dx(ring,
+							ring->hw_head);
+				++ring->stats.rx.jumbo_packets;
 			}
 		}
 	}

The commit for this change in Linux stable tree is eaeb3b7 (patch).

Last modified: 2020/02/08