net: atlantic: checksum compat issue

Yet another checksum offload compatibility issue was found.

The known issue is that AQC HW marks tcp packets with 0xFFFF checksum
as invalid (1). This is workarounded in driver, passing all the suspicious
packets up to the stack for further csum validation.

Another HW problem (2) is that it hides invalid csum of LRO aggregated
packets inside of the individual descriptors. That was workarounded
by forced scan of all LRO descriptors for checksum errors.

However the scan logic was joint for both LRO and multi-descriptor
packets (jumbos). And this causes the issue.

We have to drop LRO packets with the detected bad checksum
because of (2), but we have to pass jumbo packets to stack because of (1).

When using windows tcp partner with jumbo frames but with LSO disabled
driver discards such frames as bad checksummed. But only LRO frames
should be dropped, not jumbos.

On such a configurations tcp stream have a chance of drops and stucks.

(1) 76f254d4afe2 ("net: aquantia: tcp checksum 0xffff being handled incorrectly")
(2) d08b9a0a3ebd ("net: aquantia: do not pass lro session with invalid tcp checksum")

Fixes: d08b9a0a3ebd ("net: aquantia: do not pass lro session with invalid tcp checksum")
Signed-off-by: Dmitry Bezrukov <dbezrukov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Dmitry Bogdanov <dbogdanov@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 951d86f8b66e8c9114510d41436c030cf7bffeb8..6941999ae845de38670b3ccf058cee2837eee53a 100644 (file)
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -351,7 +351,8 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
                                err = 0;
                                goto err_exit;
                        }
-                       if (buff->is_error || buff->is_cso_err) {
+                       if (buff->is_error ||
+                           (buff->is_lro && buff->is_cso_err)) {
                                buff_ = buff;
                                do {
                                        next_ = buff_->next,

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.h b/drivers/net/ethernet/aquantia/atlantic/aq_ring.h
index 991e4d31b0948e86e21299c069d3bc70a738b3b0..2c96f20f62891dbec2184039cce3a7de952a6b14 100644 (file)
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.h
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.h
@@ -78,7 +78,8 @@ struct __packed aq_ring_buff_s {
                        u32 is_cleaned:1;
                        u32 is_error:1;
                        u32 is_vlan:1;
-                       u32 rsvd3:4;
+                       u32 is_lro:1;
+                       u32 rsvd3:3;
                        u16 eop_index;
                        u16 rsvd4;
                };

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 ec041f78d0634426d76e23a23678c6be8321a69b..5784da26f86834f708870ae649d3cce08d50d254 100644 (file)
--- a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
+++ b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
@@ -823,6 +823,8 @@ static int hw_atl_b0_hw_ring_rx_receive(struct aq_hw_s *self,
                        }
                }
 
+               buff->is_lro = !!(HW_ATL_B0_RXD_WB_STAT2_RSCCNT &
+                                 rxd_wb->status);
                if (HW_ATL_B0_RXD_WB_STAT2_EOP & rxd_wb->status) {
                        buff->len = rxd_wb->pkt_len %
                                AQ_CFG_RX_FRAME_MAX;
@@ -835,8 +837,7 @@ static int hw_atl_b0_hw_ring_rx_receive(struct aq_hw_s *self,
                                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) {
+                       if (buff->is_lro) {
                                /* LRO */
                                buff->next = rxd_wb->next_desc_ptr;
                                ++ring->stats.rx.lro_packets;