[PATCH v2] skge: fix broken driver

Mikulas Patocka
2013-09-19T18:13:26Z

The patch 136d8f377e1575463b47840bc5f1b22d94bf8f63 broke the skge driver.
Note this part of the patch:
+ if (skge_rx_setup(skge, e, nskb, skge->rx_buf_size) < 0) {
+ dev_kfree_skb(nskb);
+ goto resubmit;
+ }
+
pci_unmap_single(skge->hw->pdev,
dma_unmap_addr(e, mapaddr),
dma_unmap_len(e, maplen),
PCI_DMA_FROMDEVICE);
skb = e->skb;
prefetch(skb->data);
- skge_rx_setup(skge, e, nskb, skge->rx_buf_size);

The function skge_rx_setup modifies e->skb to point to the new skb. Thus,
after this change, the new buffer, not the old, is returned to the
networking stack.

This bug is present in kernels 3.11, 3.11.1 and 3.12-rc1. The patch should
be queued for 3.11-stable.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Vasiliy Glazov <vascom2@gmail.com>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>

---
drivers/net/ethernet/marvell/skge.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-3.11.1-fast/drivers/net/ethernet/marvell/skge.c
===================================================================
--- linux-3.11.1-fast.orig/drivers/net/ethernet/marvell/skge.c 2013-09-10 19:46:58.000000000 +0200
+++ linux-3.11.1-fast/drivers/net/ethernet/marvell/skge.c 2013-09-19 18:20:43.000000000 +0200
@@ -3092,6 +3092,9 @@ static struct sk_buff *skge_rx_get(struc
if (!nskb)
goto resubmit;

+ skb = e->skb;
+ prefetch(skb->data);
+
if (skge_rx_setup(skge, e, nskb, skge->rx_buf_size) < 0) {
dev_kfree_skb(nskb);
goto resubmit;
@@ -3101,8 +3104,6 @@ static struct sk_buff *skge_rx_get(struc
dma_unmap_addr(e, mapaddr),
dma_unmap_len(e, maplen),
PCI_DMA_FROMDEVICE);
- skb = e->skb;
- prefetch(skb->data);
}

skb_put(skb, len);