diff mbox series

[net-next,26/27] ipv6: improve opt-less __ip6_make_skb()

Message ID dd7d8a73db3ba0276a164ef5a4d9f898bff52b0f.1648981571.git.asml.silence@gmail.com (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series net and/or udp optimisations | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 3 maintainers not CCed: yoshfuji@linux-ipv6.org dsahern@kernel.org pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 25 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Pavel Begunkov April 3, 2022, 1:06 p.m. UTC 
We do a bit of a network header pointer shuffling in __ip6_make_skb()
expecting that ipv6_push_*frag_opts() might change the layout. Avoid it
with associated overhead when there are no opts.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 net/ipv6/ip6_output.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 3c37b07cbfae..f7c092af64f5 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1882,22 +1882,20 @@  struct sk_buff *__ip6_make_skb(struct sock *sk,
 
 	/* Allow local fragmentation. */
 	skb->ignore_df = ip6_sk_ignore_df(sk);
-	__skb_pull(skb, skb_network_header_len(skb));
-
 	final_dst = &fl6->daddr;
 	if (v6_cork->opt) {
 		struct ipv6_txoptions *opt = v6_cork->opt;
 
+		__skb_pull(skb, skb_network_header_len(skb));
 		if (opt->opt_flen)
 			ipv6_push_frag_opts(skb, opt, &proto);
 		if (opt->opt_nflen)
 			ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
+		skb_push(skb, sizeof(struct ipv6hdr));
+		skb_reset_network_header(skb);
 	}
 
-	skb_push(skb, sizeof(struct ipv6hdr));
-	skb_reset_network_header(skb);
 	hdr = ipv6_hdr(skb);
-
 	ip6_flow_hdr(hdr, v6_cork->tclass,
 		     ip6_make_flowlabel(net, skb, fl6->flowlabel,
 					ip6_autoflowlabel(net, np), fl6));