diff options
author | Tung Nguyen <tung.q.nguyen@dektech.com.au> | 2018-06-28 23:25:04 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2018-06-30 14:48:16 +0300 |
commit | ef9be755697f1b841c2a219a05df1a72ccd6f471 (patch) | |
tree | df97059feff846ba6f30769f9096a90b4c2b29b5 | |
parent | 9ca78674eb6a19acbb1d69e86273ebd1d3edf087 (diff) |
tipc: eliminate buffer cloning in function tipc_msg_extract()
The function tipc_msg_extract() is using skb_clone() to clone inner
messages from a message bundle buffer. Although this method is safe,
it has an undesired effect that each buffer clone inherits the
true-size of the bundling buffer. As a result, the buffer clone
almost always ends up with being copied anyway by the message
validation function. This makes the cloning into a sub-optimization.
In this commit we take the consequence of this realization, and copy
each inner message to a separately allocated buffer up front in the
extraction function.
As a bonus we can now eliminate the two cases where we had to copy
re-routed packets that may potentially go out on the wire again.
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | net/tipc/msg.c | 35 |
1 files changed, 15 insertions, 20 deletions
diff --git a/net/tipc/msg.c b/net/tipc/msg.c index b6c45dccba3d..b61891054709 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -416,26 +416,31 @@ bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu) */ bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos) { - struct tipc_msg *msg; - int imsz, offset; + struct tipc_msg *hdr, *ihdr; + int imsz; *iskb = NULL; if (unlikely(skb_linearize(skb))) goto none; - msg = buf_msg(skb); - offset = msg_hdr_sz(msg) + *pos; - if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE))) + hdr = buf_msg(skb); + if (unlikely(*pos > (msg_data_sz(hdr) - MIN_H_SIZE))) goto none; - *iskb = skb_clone(skb, GFP_ATOMIC); - if (unlikely(!*iskb)) + ihdr = (struct tipc_msg *)(msg_data(hdr) + *pos); + imsz = msg_size(ihdr); + + if ((*pos + imsz) > msg_data_sz(hdr)) goto none; - skb_pull(*iskb, offset); - imsz = msg_size(buf_msg(*iskb)); - skb_trim(*iskb, imsz); + + *iskb = tipc_buf_acquire(imsz, GFP_ATOMIC); + if (!*iskb) + goto none; + + skb_copy_to_linear_data(*iskb, ihdr, imsz); if (unlikely(!tipc_msg_validate(iskb))) goto none; + *pos += align(imsz); return true; none: @@ -531,12 +536,6 @@ bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err) msg_set_hdr_sz(hdr, BASIC_H_SIZE); } - if (skb_cloned(_skb) && - pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC)) - goto exit; - - /* reassign after skb header modifications */ - hdr = buf_msg(_skb); /* Now reverse the concerned fields */ msg_set_errcode(hdr, err); msg_set_non_seq(hdr, 0); @@ -595,10 +594,6 @@ bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err) if (!skb_cloned(skb)) return true; - /* Unclone buffer in case it was bundled */ - if (pskb_expand_head(skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC)) - return false; - return true; } |