3.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Amir Vadai <am...@mellanox.com>

[ Upstream commit 021f1107ffdae7a82af6c53f4c52654062e365c6 ]

This patch fixes a bug introduced by commit 51151a16 (mlx4: allow
order-0 memory allocations in RX path).

dma_unmap_page never reached because condition to detect last fragment
in page is wrong. offset+frag_stride can't be greater than size, need to
make sure no additional frag will fit in page => compare offset +
frag_stride + next_frag_size instead.
next_frag_size is the same as the current one, since page is shared only
with frags of the same size.

CC: Eric Dumazet <eduma...@google.com>
Signed-off-by: Amir Vadai <am...@mellanox.com>
Acked-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx4/en_rx.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -135,9 +135,10 @@ static void mlx4_en_free_frag(struct mlx
                              int i)
 {
        const struct mlx4_en_frag_info *frag_info = &priv->frag_info[i];
+       u32 next_frag_end = frags[i].page_offset + 2 * frag_info->frag_stride;
 
-       if (frags[i].page_offset + frag_info->frag_stride >
-           frags[i].page_size)
+
+       if (next_frag_end > frags[i].page_size)
                dma_unmap_page(priv->ddev, frags[i].dma, frags[i].page_size,
                               PCI_DMA_FROMDEVICE);
 


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