From: Michal Schmidt <mschmidt@redhat.com>
Date: Fri, 3 Sep 2010 16:41:25 -0400
Subject: [net] bnx2x: make NAPI poll routine closer to upstream
Message-id: <20100903164125.25415.73713.stgit@brian.englab.brq.redhat.com>
Patchwork-id: 28079
O-Subject: [RHEL5.6 BZ572012 PATCH 04/46] bnx2x: make the NAPI poll routine
	closer to upstream
Bugzilla: 572012
RH-Acked-by: David S. Miller <davem@redhat.com>
RH-Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>

from upstream 54b9ddaa68414fad72ab2e1042be067c902441a6:
    bnx2x: Handle Rx and Tx together in NAPI

    Put Tx and Rx DPC to be handled in the NAPI:
      - Saves status blocks.
      - Moves the Tx work from hardIRQ to NAPI.

A bigger part of the commit was already in RHEL. Only the bnx2x_poll()
piece was missing.

diff --git a/drivers/net/bnx2x_main.c b/drivers/net/bnx2x_main.c
index 788f031..4bc1e08 100644
--- a/drivers/net/bnx2x_main.c
+++ b/drivers/net/bnx2x_main.c
@@ -10956,58 +10956,67 @@ static inline int bnx2x_has_rx_work(struct bnx2x_fastpath *fp)
 
 static int bnx2x_poll(struct net_device *dev, int *budget)
 {
+	int work_done = 0;
 	struct bnx2x_fastpath *fp = dev->priv;
 	struct bnx2x *bp = fp->bp;
 	int work_to_do = min(*budget, dev->quota);
-	int work_done = 0;
+	int more_poll = 1;
 
+	while (1) {
 #ifdef BNX2X_STOP_ON_ERROR
-	if (unlikely(bp->panic))
-		goto poll_panic;
+		if (unlikely(bp->panic)) {
+			napi_gro_flush(&fp->napi);
+			netif_rx_complete(dev);
+			more_poll = 0;
+			break;
+		}
 #endif
 
-	prefetch(fp->tx_buf_ring[TX_BD(fp->tx_pkt_cons)].skb);
-	prefetch(fp->rx_buf_ring[RX_BD(fp->rx_bd_cons)].skb);
-	prefetch((char *)(fp->rx_buf_ring[RX_BD(fp->rx_bd_cons)].skb) + 256);
-
-	bnx2x_update_fpsb_idx(fp);
-
-	if (bnx2x_has_tx_work(fp))
-		bnx2x_tx_int(fp);
-
-	if (bnx2x_has_rx_work(fp)) {
-		work_done = bnx2x_rx_int(fp, work_to_do);
+		if (bnx2x_has_tx_work(fp))
+			bnx2x_tx_int(fp);
 
-		*budget -= work_done;
-		dev->quota -= work_done;
-	}
+		if (bnx2x_has_rx_work(fp)) {
+			work_done += bnx2x_rx_int(fp, work_to_do - work_done);
 
-	/* bnx2x_has_rx_work() reads the status block, thus we need to
-	 * ensure that status block indices have been actually read
-	 * (bnx2x_update_fpsb_idx) prior to this check (bnx2x_has_rx_work)
-	 * so that we won't write the "newer" value of the status block to IGU
-	 * (if there was a DMA right after bnx2x_has_rx_work and
-	 * if there is no rmb, the memory reading (bnx2x_update_fpsb_idx)
-	 * may be postponed to right before bnx2x_ack_sb). In this case
-	 * there will never be another interrupt until there is another update
-	 * of the status block, while there is still unhandled work.
-	 */
-	rmb();
+			/* must not complete if we consumed full budget */
+			if (work_done >= work_to_do)
+				break;
+		}
 
-	if (!bnx2x_has_rx_work(fp)) {
-#ifdef BNX2X_STOP_ON_ERROR
-poll_panic:
-#endif
-		napi_gro_flush(&fp->napi);
-		netif_rx_complete(dev);
+		/* Fall out from the NAPI loop if needed */
+		if (!(bnx2x_has_rx_work(fp) || bnx2x_has_tx_work(fp))) {
+			bnx2x_update_fpsb_idx(fp);
+		/* bnx2x_has_rx_work() reads the status block, thus we need
+		 * to ensure that status block indices have been actually read
+		 * (bnx2x_update_fpsb_idx) prior to this check
+		 * (bnx2x_has_rx_work) so that we won't write the "newer"
+		 * value of the status block to IGU (if there was a DMA right
+		 * after bnx2x_has_rx_work and if there is no rmb, the memory
+		 * reading (bnx2x_update_fpsb_idx) may be postponed to right
+		 * before bnx2x_ack_sb). In this case there will never be
+		 * another interrupt until there is another update of the
+		 * status block, while there is still unhandled work.
+		 */
+			rmb();
 
-		bnx2x_ack_sb(bp, fp->sb_id, USTORM_ID,
-			     le16_to_cpu(fp->fp_u_idx), IGU_INT_NOP, 1);
-		bnx2x_ack_sb(bp, fp->sb_id, CSTORM_ID,
-			     le16_to_cpu(fp->fp_c_idx), IGU_INT_ENABLE, 1);
-		return 0;
+			if (!(bnx2x_has_rx_work(fp) || bnx2x_has_tx_work(fp))) {
+				napi_gro_flush(&fp->napi);
+				netif_rx_complete(dev);
+				/* Re-enable interrupts */
+				bnx2x_ack_sb(bp, fp->sb_id, CSTORM_ID,
+					     le16_to_cpu(fp->fp_c_idx),
+					     IGU_INT_NOP, 1);
+				bnx2x_ack_sb(bp, fp->sb_id, USTORM_ID,
+					     le16_to_cpu(fp->fp_u_idx),
+					     IGU_INT_ENABLE, 1);
+				more_poll = 0;
+				break;
+			}
+		}
 	}
-	return 1;
+	*budget -= work_done;
+	dev->quota -= work_done;
+	return more_poll;
 }