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[3.8.y.z,extended,stable] Patch "atl1e: unmap partially mapped skb on dma error and free skb" has been added to staging queue

Message ID 1374798251-6949-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa July 26, 2013, 12:24 a.m. UTC
This is a note to let you know that I have just added a patch titled

    atl1e: unmap partially mapped skb on dma error and free skb

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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From c1dab674041921ad73bdb3d36f4cbacf330bfb0a 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

[ 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: Kamal Mostafa <kamal@canonical.com>
---
 drivers/net/ethernet/atheros/atl1e/atl1e_main.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

--
1.8.1.2
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Patch

diff --git a/drivers/net/ethernet/atheros/atl1e/atl1e_main.c b/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
index a756cd4..62cb33c 100644
--- a/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
+++ b/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
@@ -1682,6 +1682,7 @@  static int atl1e_tx_map(struct atl1e_adapter *adapter,
 	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;
@@ -1725,6 +1726,15 @@  static int atl1e_tx_map(struct atl1e_adapter *adapter,
 					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;
@@ -1767,6 +1777,16 @@  static int atl1e_tx_map(struct atl1e_adapter *adapter,
 							  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;
@@ -1857,8 +1877,10 @@  static netdev_tx_t atl1e_xmit_frame(struct sk_buff *skb,
 		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);