[net-next-2.6 PATCH 18/18] igb: update tx DMA mapping error handling

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

From: Nick Nunley <nicholasx.d.nunley@intel.com>

This updates the tx DMA mapping error handling code to
resemble e1000e/ixgbe.

Signed-off-by: Nicholas Nunley <nicholasx.d.nunley@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

 drivers/net/igb/igb_main.c |    8 +++-----
 1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index ab7c5e9..f588e49 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -3647,14 +3647,12 @@ dma_error:
 	buffer_info->length = 0;
 	buffer_info->next_to_watch = 0;
 	buffer_info->mapped_as_page = false;
-	count--;
 
 	/* clear timestamp and dma mappings for remaining portion of packet */
-	while (count >= 0) {
-		count--;
+	while (count--) {
+		if (i == 0)
+			i = tx_ring->count;
 		i--;
-		if (i < 0)
-			i += tx_ring->count;
 		buffer_info = &tx_ring->buffer_info[i];
 		igb_unmap_and_free_tx_resource(tx_ring, buffer_info);
 	}