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6fa01ccd88
A pattern of skb usage seen in modules such as RDS-TCP is to extract `to_copy' bytes from the received TCP segment, starting at some offset `off' into a new skb `clone'. This is done in the ->data_ready callback, where the clone skb is queued up for rx on the PF_RDS socket, while the parent TCP segment is returned unchanged back to the TCP engine. The existing code uses the sequence clone = skb_clone(..); pskb_pull(clone, off, ..); pskb_trim(clone, to_copy, ..); with the intention of discarding the first `off' bytes. However, skb_clone() + pskb_pull() implies pksb_expand_head(), which ends up doing a redundant memcpy of bytes that will then get discarded in __pskb_pull_tail(). To avoid this inefficiency, this commit adds pskb_extract() that creates the clone, and memcpy's only the relevant header/frag/frag_list to the start of `clone'. pskb_trim() is then invoked to trim clone down to the requested to_copy bytes. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| datagram.c | ||
| dev.c | ||
| dev_addr_lists.c | ||
| dev_ioctl.c | ||
| devlink.c | ||
| drop_monitor.c | ||
| dst.c | ||
| dst_cache.c | ||
| ethtool.c | ||
| fib_rules.c | ||
| filter.c | ||
| flow.c | ||
| flow_dissector.c | ||
| gen_estimator.c | ||
| gen_stats.c | ||
| hwbm.c | ||
| link_watch.c | ||
| lwtunnel.c | ||
| Makefile | ||
| neighbour.c | ||
| net-procfs.c | ||
| net-sysfs.c | ||
| net-sysfs.h | ||
| net-traces.c | ||
| net_namespace.c | ||
| netclassid_cgroup.c | ||
| netevent.c | ||
| netpoll.c | ||
| netprio_cgroup.c | ||
| pktgen.c | ||
| ptp_classifier.c | ||
| request_sock.c | ||
| rtnetlink.c | ||
| scm.c | ||
| secure_seq.c | ||
| skbuff.c | ||
| sock.c | ||
| sock_diag.c | ||
| sock_reuseport.c | ||
| stream.c | ||
| sysctl_net_core.c | ||
| timestamping.c | ||
| tso.c | ||
| utils.c | ||