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hv_netvsc: Restore needed_headroom request 

Commit c0eb454034 ("hv_netvsc: Don't ask for additional head room in the
skb") got rid of needed_headroom setting for the driver. With the change I
hit the following issue trying to use ptkgen module:

[   57.522021] kernel BUG at net/core/skbuff.c:1128!
[   57.522021] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
...
[   58.721068] Call Trace:
[   58.721068]  [<ffffffffa0144e86>] netvsc_start_xmit+0x4c6/0x8e0 [hv_netvsc]
...
[   58.721068]  [<ffffffffa02f87fc>] ? pktgen_finalize_skb+0x25c/0x2a0 [pktgen]
[   58.721068]  [<ffffffff814f5760>] ? __netdev_alloc_skb+0xc0/0x100
[   58.721068]  [<ffffffffa02f9907>] pktgen_thread_worker+0x257/0x1920 [pktgen]

Basically, we're calling skb_cow_head(skb, RNDIS_AND_PPI_SIZE) and crash on
    if (skb_shared(skb))
        BUG();

We probably need to restore needed_headroom setting (but shrunk to
RNDIS_AND_PPI_SIZE as we don't need more) to request the required headroom
space. In theory, it should not give us performance penalty.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vitaly Kuznetsov 2016-02-05 17:29:08 +01:00 committed by David S. Miller
parent 603607de0c
commit 14a03cf80e
1 changed files with 3 additions and 0 deletions
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3
drivers/net/hyperv/netvsc_drv.c
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@ -1089,6 +1089,9 @@ static int netvsc_probe(struct hv_device *dev,
net->ethtool_ops = &ethtool_ops; net->ethtool_ops = &ethtool_ops;
SET_NETDEV_DEV(net, &dev->device); SET_NETDEV_DEV(net, &dev->device);
/* We always need headroom for rndis header */
net->needed_headroom = RNDIS_AND_PPI_SIZE;
/* Notify the netvsc driver of the new device */ /* Notify the netvsc driver of the new device */
memset(&device_info, 0, sizeof(device_info)); memset(&device_info, 0, sizeof(device_info));
device_info.ring_size = ring_size; device_info.ring_size = ring_size;