netdev - [net-2.6 PATCH 2/2] e1000: fix transmit routine exit bug

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Message-ID: <20090417025946.19671.21412.stgit@localhost.localdomain>
Date:	Thu, 16 Apr 2009 19:59:47 -0700
From:	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, gospo@...hat.com,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-2.6 PATCH 2/2] e1000: fix transmit routine exit bug

From: Jesse Brandeburg <jesse.brandeburg@...el.com>

If the e1000 transmit cleanup inner loop exited early, then
cleaned might not be true.  This could cause tx hangs or other
badness.  Use count to track the total number of descriptors
cleaned instead of basing a tx queue restart off of a temporary
working state variable.

This code now makes the flow the same for e1000/e1000e/igb/ixgbe

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---

 drivers/net/e1000/e1000_main.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index ef12931..6a46cee 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3834,7 +3834,6 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter,
 	struct e1000_buffer *buffer_info;
 	unsigned int i, eop;
 	unsigned int count = 0;
-	bool cleaned = false;
 	unsigned int total_tx_bytes=0, total_tx_packets=0;
 
 	i = tx_ring->next_to_clean;
@@ -3843,7 +3842,8 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter,
 
 	while ((eop_desc->upper.data & cpu_to_le32(E1000_TXD_STAT_DD)) &&
 	       (count < tx_ring->count)) {
-		for (cleaned = false; !cleaned; count++) {
+		bool cleaned = false;
+		for ( ; !cleaned; count++) {
 			tx_desc = E1000_TX_DESC(*tx_ring, i);
 			buffer_info = &tx_ring->buffer_info[i];
 			cleaned = (i == eop);
@@ -3871,7 +3871,7 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter,
 	tx_ring->next_to_clean = i;
 
 #define TX_WAKE_THRESHOLD 32
-	if (unlikely(cleaned && netif_carrier_ok(netdev) &&
+	if (unlikely(count && netif_carrier_ok(netdev) &&
 		     E1000_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD)) {
 		/* Make sure that anybody stopping the queue after this
 		 * sees the new next_to_clean.

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