releases/3.10.4/atl1e-unmap-partially-mapped-skb-on-dma-error-and-free-skb.patch

From 326eb306b8445bccf894e99ccde478eb4731b726 Mon Sep 17 00:00:00 2001
From: Neil Horman <nhorman@tuxdriver.com>
Date: Tue, 16 Jul 2013 10:49:41 -0400
Subject: atl1e: unmap partially mapped skb on dma error and free skb

From: Neil Horman <nhorman@tuxdriver.com>

[ Upstream commit 584ec4355355ffac43571b02a314d43eb2f7fcbf ]

Ben Hutchings pointed out that my recent update to atl1e
in commit 352900b583b2852152a1e05ea0e8b579292e731e
("atl1e: fix dma mapping warnings") was missing a bit of code.

Specifically it reset the hardware tx ring to its origional state when
we hit a dma error, but didn't unmap any exiting mappings from the
operation.  This patch fixes that up.  It also remembers to free the
skb in the event that an error occurs, so we don't leak.  Untested, as
I don't have hardware.  I think its pretty straightforward, but please
review closely.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Jay Cliburn <jcliburn@gmail.com>
CC: Chris Snook <chris.snook@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/atheros/atl1e/atl1e_main.c |   24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
+++ b/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
@@ -1678,6 +1678,7 @@ static int atl1e_tx_map(struct atl1e_ada
 	u16 f;
 	int segment;
 	int ring_start = adapter->tx_ring.next_to_use;
+	int ring_end;
 
 	nr_frags = skb_shinfo(skb)->nr_frags;
 	segment = (tpd->word3 >> TPD_SEGMENT_EN_SHIFT) & TPD_SEGMENT_EN_MASK;
@@ -1721,6 +1722,15 @@ static int atl1e_tx_map(struct atl1e_ada
 					map_len, PCI_DMA_TODEVICE);
 
 		if (dma_mapping_error(&adapter->pdev->dev, tx_buffer->dma)) {
+			/* We need to unwind the mappings we've done */
+			ring_end = adapter->tx_ring.next_to_use;
+			adapter->tx_ring.next_to_use = ring_start;
+			while (adapter->tx_ring.next_to_use != ring_end) {
+				tpd = atl1e_get_tpd(adapter);
+				tx_buffer = atl1e_get_tx_buffer(adapter, tpd);
+				pci_unmap_single(adapter->pdev, tx_buffer->dma,
+						 tx_buffer->length, PCI_DMA_TODEVICE);
+			}
 			/* Reset the tx rings next pointer */
 			adapter->tx_ring.next_to_use = ring_start;
 			return -ENOSPC;
@@ -1763,6 +1773,16 @@ static int atl1e_tx_map(struct atl1e_ada
 							  DMA_TO_DEVICE);
 
 			if (dma_mapping_error(&adapter->pdev->dev, tx_buffer->dma)) {
+				/* We need to unwind the mappings we've done */
+				ring_end = adapter->tx_ring.next_to_use;
+				adapter->tx_ring.next_to_use = ring_start;
+				while (adapter->tx_ring.next_to_use != ring_end) {
+					tpd = atl1e_get_tpd(adapter);
+					tx_buffer = atl1e_get_tx_buffer(adapter, tpd);
+					dma_unmap_page(&adapter->pdev->dev, tx_buffer->dma,
+						       tx_buffer->length, DMA_TO_DEVICE);
+				}
+
 				/* Reset the ring next to use pointer */
 				adapter->tx_ring.next_to_use = ring_start;
 				return -ENOSPC;
@@ -1853,8 +1873,10 @@ static netdev_tx_t atl1e_xmit_frame(stru
 		return NETDEV_TX_OK;
 	}
 
-	if (atl1e_tx_map(adapter, skb, tpd))
+	if (atl1e_tx_map(adapter, skb, tpd)) {
+		dev_kfree_skb_any(skb);
 		goto out;
+	}
 
 	atl1e_tx_queue(adapter, tpd_req, tpd);