netdev - [PATCH net 2/2] bnxt_en: Fix netpoll handling.

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Date:   Fri, 23 Jun 2017 14:01:01 -0400
From:   Michael Chan <michael.chan@...adcom.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: [PATCH net 2/2] bnxt_en: Fix netpoll handling.

To handle netpoll properly, the driver must only handle TX packets
during NAPI.  Handling RX events cause warnings and errors in
netpoll mode. The ndo_poll_controller() method should call
napi_schedule() directly so that a NAPI weight of zero will be used
during netpoll mode.

The bnxt_en driver supports 2 ring modes: combined, and separate rx/tx.
In separate rx/tx mode, the ndo_poll_controller() method will only
process the tx rings.  In combined mode, the rx and tx completion
entries are mixed in the completion ring and we need to drop the rx
entries and recycle the rx buffers.

Add a function bnxt_force_rx_discard() to handle this in netpoll mode
when we see rx entries in combined ring mode.

Reported-by: Calvin Owens <calvinowens@...com>
Signed-off-by: Michael Chan <michael.chan@...adcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 54 +++++++++++++++++++++++++++----
 1 file changed, 48 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index f5ba8ec..74e8e21 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -1563,6 +1563,45 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_napi *bnapi, u32 *raw_cons,
 	return rc;
 }
 
+/* In netpoll mode, if we are using a combined completion ring, we need to
+ * discard the rx packets and recycle the buffers.
+ */
+static int bnxt_force_rx_discard(struct bnxt *bp, struct bnxt_napi *bnapi,
+				 u32 *raw_cons, u8 *event)
+{
+	struct bnxt_cp_ring_info *cpr = &bnapi->cp_ring;
+	u32 tmp_raw_cons = *raw_cons;
+	struct rx_cmp_ext *rxcmp1;
+	struct rx_cmp *rxcmp;
+	u16 cp_cons;
+	u8 cmp_type;
+
+	cp_cons = RING_CMP(tmp_raw_cons);
+	rxcmp = (struct rx_cmp *)
+			&cpr->cp_desc_ring[CP_RING(cp_cons)][CP_IDX(cp_cons)];
+
+	tmp_raw_cons = NEXT_RAW_CMP(tmp_raw_cons);
+	cp_cons = RING_CMP(tmp_raw_cons);
+	rxcmp1 = (struct rx_cmp_ext *)
+			&cpr->cp_desc_ring[CP_RING(cp_cons)][CP_IDX(cp_cons)];
+
+	if (!RX_CMP_VALID(rxcmp1, tmp_raw_cons))
+		return -EBUSY;
+
+	cmp_type = RX_CMP_TYPE(rxcmp);
+	if (cmp_type == CMP_TYPE_RX_L2_CMP) {
+		rxcmp1->rx_cmp_cfa_code_errors_v2 |=
+			cpu_to_le32(RX_CMPL_ERRORS_CRC_ERROR);
+	} else if (cmp_type == CMP_TYPE_RX_L2_TPA_END_CMP) {
+		struct rx_tpa_end_cmp_ext *tpa_end1;
+
+		tpa_end1 = (struct rx_tpa_end_cmp_ext *)rxcmp1;
+		tpa_end1->rx_tpa_end_cmp_errors_v2 |=
+			cpu_to_le32(RX_TPA_END_CMP_ERRORS);
+	}
+	return bnxt_rx_pkt(bp, bnapi, raw_cons, event);
+}
+
 #define BNXT_GET_EVENT_PORT(data)	\
 	((data) &			\
 	 ASYNC_EVENT_CMPL_PORT_CONN_NOT_ALLOWED_EVENT_DATA1_PORT_ID_MASK)
@@ -1745,7 +1784,11 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_napi *bnapi, int budget)
 			if (unlikely(tx_pkts > bp->tx_wake_thresh))
 				rx_pkts = budget;
 		} else if ((TX_CMP_TYPE(txcmp) & 0x30) == 0x10) {
-			rc = bnxt_rx_pkt(bp, bnapi, &raw_cons, &event);
+			if (likely(budget))
+				rc = bnxt_rx_pkt(bp, bnapi, &raw_cons, &event);
+			else
+				rc = bnxt_force_rx_discard(bp, bnapi, &raw_cons,
+							   &event);
 			if (likely(rc >= 0))
 				rx_pkts += rc;
 			else if (rc == -EBUSY)	/* partial completion */
@@ -6664,12 +6707,11 @@ static void bnxt_poll_controller(struct net_device *dev)
 	struct bnxt *bp = netdev_priv(dev);
 	int i;
 
-	for (i = 0; i < bp->cp_nr_rings; i++) {
-		struct bnxt_irq *irq = &bp->irq_tbl[i];
+	/* Only process tx rings/combined rings in netpoll mode. */
+	for (i = 0; i < bp->tx_nr_rings; i++) {
+		struct bnxt_tx_ring_info *txr = &bp->tx_ring[i];
 
-		disable_irq(irq->vector);
-		irq->handler(irq->vector, bp->bnapi[i]);
-		enable_irq(irq->vector);
+		napi_schedule(&txr->bnapi->napi);
 	}
 }
 #endif
-- 
1.8.3.1