I/OAT: tcp_dma_copybreak default value dependent on I/OAT version

I/OAT DMA performance tuning showed different optimal values of
tcp_dma_copybreak for different I/OAT versions (4096 for 1.2 and 2048
for 2.0).  This patch lets ioatdma driver set tcp_dma_copybreak value
according to these results.

[dan.j.williams@intel.com: remove some ifdefs]
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/core/user_dma.c b/net/core/user_dma.c
index 0ad1cd57bc39..de760504f6fe 100644
--- a/net/core/user_dma.c
+++ b/net/core/user_dma.c
@@ -34,6 +34,7 @@
 #define NET_DMA_DEFAULT_COPYBREAK 4096
 
 int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK;
+EXPORT_SYMBOL(sysctl_tcp_dma_copybreak);
 
 /**
  *      dma_skb_copy_datagram_iovec - Copy a datagram to an iovec.