bnxt_en: Add workaround to detect bad opaque in rx completion (part 1)

There is a rare hardware bug that can cause a bad opaque value in the RX
or TPA completion.  When this happens, the hardware may have used the
same buffer twice for 2 rx packets.  In addition, the driver will also
crash later using the bad opaque as the index into the ring.

The rx opaque value is predictable and is always monotonically increasing.
The workaround is to keep track of the expected next opaque value and
compare it with the one returned by hardware during RX and TPA start
completions.  If they miscompare, we will not process any more RX and
TPA completions and exit NAPI.  We will then schedule a workqueue to
reset the function.

This patch adds the logic to keep track of the next rx consumer index.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 9d4e8e113fe18f564060d48a6e686f5a4c79dadd..58999cdd3675760c07bb99632257074eb8e598a8 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -867,6 +867,7 @@ static void bnxt_tpa_start(struct bnxt *bp, struct bnxt_rx_ring_info *rxr,
 
        rxr->rx_prod = NEXT_RX(prod);
        cons = NEXT_RX(cons);
+       rxr->rx_next_cons = NEXT_RX(cons);
        cons_rx_buf = &rxr->rx_buf_ring[cons];
 
        bnxt_reuse_rx_data(rxr, cons, cons_rx_buf->data);
@@ -1245,6 +1246,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_napi *bnapi, u32 *raw_cons,
 
 next_rx:
        rxr->rx_prod = NEXT_RX(prod);
+       rxr->rx_next_cons = NEXT_RX(cons);
 
 next_rx_no_prod:
        *raw_cons = tmp_raw_cons;
@@ -2486,6 +2488,7 @@ static void bnxt_clear_ring_indices(struct bnxt *bp)
                        rxr->rx_prod = 0;
                        rxr->rx_agg_prod = 0;
                        rxr->rx_sw_agg_prod = 0;
+                       rxr->rx_next_cons = 0;
                }
        }
 }

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 8b823ff558ffe2ab81422c0ce6bdfa61d3bc2b20..52f2d74a0d0462e6d257561ea0472ef3825f0c89 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -584,6 +584,7 @@ struct bnxt_rx_ring_info {
        u16                     rx_prod;
        u16                     rx_agg_prod;
        u16                     rx_sw_agg_prod;
+       u16                     rx_next_cons;
        void __iomem            *rx_doorbell;
        void __iomem            *rx_agg_doorbell;