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| author |   Willem de Bruijn <willemb@google.com> | 2017-08-03 16:29:41 -0400 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-08-03 21:37:30 -0700 |
| commit | 1f8b977ab32dc5d148f103326e80d9097f1cefb5 (patch) | |
| tree | 1c2c09ca72dba5bd43f8b3ead791d271f075c24b /net/core/dev.c | |
| parent | sock: add SOCK_ZEROCOPY sockopt (diff) | |
| download | linux-dev-1f8b977ab32dc5d148f103326e80d9097f1cefb5.tar.xz linux-dev-1f8b977ab32dc5d148f103326e80d9097f1cefb5.zip | |
sock: enable MSG_ZEROCOPY
Prepare the datapath for refcounted ubuf_info. Clone ubuf_info with
skb_zerocopy_clone() wherever needed due to skb split, merge, resize
or clone.
Split skb_orphan_frags into two variants. The split, merge, .. paths
support reference counted zerocopy buffers, so do not do a deep copy.
Add skb_orphan_frags_rx for paths that may loop packets to receive
sockets. That is not allowed, as it may cause unbounded latency.
Deep copy all zerocopy copy buffers, ref-counted or not, in this path.
The exact locations to modify were chosen by exhaustively searching
through all code that might modify skb_frag references and/or the
the SKBTX_DEV_ZEROCOPY tx_flags bit.
The changes err on the safe side, in two ways.
(1) legacy ubuf_info paths virtio and tap are not modified. They keep
a 1:1 ubuf_info to sk_buff relationship. Calls to skb_orphan_frags
still call skb_copy_ubufs and thus copy frags in this case.
(2) not all copies deep in the stack are addressed yet. skb_shift,
skb_split and skb_try_coalesce can be refined to avoid copying.
These are not in the hot path and this patch is hairy enough as
is, so that is left for future refinement.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 8ea6b4b42611..1d75499add72 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1853,7 +1853,7 @@ static inline int deliver_skb(struct sk_buff *skb, struct packet_type *pt_prev, struct net_device *orig_dev) { - if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) + if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) return -ENOMEM; refcount_inc(&skb->users); return pt_prev->func(skb, skb->dev, pt_prev, orig_dev); @@ -4412,7 +4412,7 @@ skip_classify: } if (pt_prev) { - if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) + if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) goto drop; else ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev); |