tg3: Give MSI-X vec 1 rx backlog space

RSS ring 1 is responsible for submitting new rx buffers to the
hardware on behalf of all the other RSS rx return rings.  Up until now
this ring submitted its new rx buffers to the producer ring directly.
The following patch will require that this ring have a place to put
backlogged rx packets.  As a consequence, it can no longer submit new
buffers to the producer ring.

This patch adds code to allocate an extra shadow producer ring for this
RSS ring and adds RSS ring 1 to the list of rings needing buffer
transfers.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -4733,7 +4733,7 @@ static int tg3_rx(struct tg3_napi *tnapi, int budget)
 	tw32_rx_mbox(tnapi->consmbox, sw_idx);
 
 	/* Refill RX ring(s). */
-	if (!(tp->tg3_flags3 & TG3_FLG3_ENABLE_RSS) || tnapi == &tp->napi[1]) {
+	if (!(tp->tg3_flags3 & TG3_FLG3_ENABLE_RSS)) {
 		if (work_mask & RXD_OPAQUE_RING_STD) {
 			tpr->rx_std_prod_idx = std_prod_idx % TG3_RX_RING_SIZE;
 			tw32_rx_mbox(TG3_RX_STD_PROD_IDX_REG,
@@ -4755,7 +4755,8 @@ static int tg3_rx(struct tg3_napi *tnapi, int budget)
 		tpr->rx_std_prod_idx = std_prod_idx % TG3_RX_RING_SIZE;
 		tpr->rx_jmb_prod_idx = jmb_prod_idx % TG3_RX_JUMBO_RING_SIZE;
 
-		napi_schedule(&tp->napi[1].napi);
+		if (tnapi != &tp->napi[1])
+			napi_schedule(&tp->napi[1].napi);
 	}
 
 	return received;
@@ -4893,25 +4894,23 @@ static int tg3_poll_work(struct tg3_napi *tnapi, int work_done, int budget)
 		work_done += tg3_rx(tnapi, budget - work_done);
 
 	if ((tp->tg3_flags3 & TG3_FLG3_ENABLE_RSS) && tnapi == &tp->napi[1]) {
+		struct tg3_rx_prodring_set *dpr = &tp->prodring[0];
 		int i;
-		u32 std_prod_idx = tp->prodring[0].rx_std_prod_idx;
-		u32 jmb_prod_idx = tp->prodring[0].rx_jmb_prod_idx;
+		u32 std_prod_idx = dpr->rx_std_prod_idx;
+		u32 jmb_prod_idx = dpr->rx_jmb_prod_idx;
 
-		for (i = 2; i < tp->irq_cnt; i++)
-			tg3_rx_prodring_xfer(tp, tnapi->prodring,
-					     tp->napi[i].prodring);
+		for (i = 1; i < tp->irq_cnt; i++)
+			tg3_rx_prodring_xfer(tp, dpr, tp->napi[i].prodring);
 
 		wmb();
 
-		if (std_prod_idx != tp->prodring[0].rx_std_prod_idx) {
-			u32 mbox = TG3_RX_STD_PROD_IDX_REG;
-			tw32_rx_mbox(mbox, tp->prodring[0].rx_std_prod_idx);
-		}
+		if (std_prod_idx != dpr->rx_std_prod_idx)
+			tw32_rx_mbox(TG3_RX_STD_PROD_IDX_REG,
+				     dpr->rx_std_prod_idx);
 
-		if (jmb_prod_idx != tp->prodring[0].rx_jmb_prod_idx) {
-			u32 mbox = TG3_RX_JMB_PROD_IDX_REG;
-			tw32_rx_mbox(mbox, tp->prodring[0].rx_jmb_prod_idx);
-		}
+		if (jmb_prod_idx != dpr->rx_jmb_prod_idx)
+			tw32_rx_mbox(TG3_RX_JMB_PROD_IDX_REG,
+				     dpr->rx_jmb_prod_idx);
 
 		mmiowb();
 	}
@@ -6173,8 +6172,7 @@ static void tg3_free_rings(struct tg3 *tp)
 			dev_kfree_skb_any(skb);
 		}
 
-		if (tp->irq_cnt == 1 || j != tp->irq_cnt - 1)
-			tg3_rx_prodring_free(tp, &tp->prodring[j]);
+		tg3_rx_prodring_free(tp, &tp->prodring[j]);
 	}
 }
 
@@ -6210,9 +6208,10 @@ static int tg3_init_rings(struct tg3 *tp)
 		if (tnapi->rx_rcb)
 			memset(tnapi->rx_rcb, 0, TG3_RX_RCB_RING_BYTES(tp));
 
-		if ((tp->irq_cnt == 1 || i != tp->irq_cnt - 1) &&
-			tg3_rx_prodring_alloc(tp, &tp->prodring[i]))
+		if (tg3_rx_prodring_alloc(tp, &tp->prodring[i])) {
+			tg3_free_rings(tp);
 			return -ENOMEM;
+		}
 	}
 
 	return 0;
@@ -6259,7 +6258,7 @@ static void tg3_free_consistent(struct tg3 *tp)
 		tp->hw_stats = NULL;
 	}
 
-	for (i = 0; i < (tp->irq_cnt == 1 ? 1 : tp->irq_cnt - 1); i++)
+	for (i = 0; i < tp->irq_cnt; i++)
 		tg3_rx_prodring_fini(tp, &tp->prodring[i]);
 }
 
@@ -6271,7 +6270,7 @@ static int tg3_alloc_consistent(struct tg3 *tp)
 {
 	int i;
 
-	for (i = 0; i < (tp->irq_cnt == 1 ? 1 : tp->irq_cnt - 1); i++) {
+	for (i = 0; i < tp->irq_cnt; i++) {
 		if (tg3_rx_prodring_init(tp, &tp->prodring[i]))
 			goto err_out;
 	}
@@ -6336,10 +6335,7 @@ static int tg3_alloc_consistent(struct tg3 *tp)
 			break;
 		}
 
-		if (tp->irq_cnt == 1)
-			tnapi->prodring = &tp->prodring[0];
-		else if (i)
-			tnapi->prodring = &tp->prodring[i - 1];
+		tnapi->prodring = &tp->prodring[i];
 
 		/*
 		 * If multivector RSS is enabled, vector 0 does not handle

drivers/net/tg3.h

@@ -2717,7 +2717,7 @@ struct tg3 {
 	struct vlan_group		*vlgrp;
 #endif
 
-	struct tg3_rx_prodring_set	prodring[TG3_IRQ_MAX_VECS - 1];
+	struct tg3_rx_prodring_set	prodring[TG3_IRQ_MAX_VECS];
 
 
 	/* begin "everything else" cacheline(s) section */