Commit b1cd687e authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

ipv6: optimize fl6_update_dst() 



fl6_update_dst() is called for every TCP (and others) transmit,
and is a nop for common cases.

Split it in two parts :

1) fl6_update_dst() inline helper, small and fast.

2) __fl6_update_dst() for the exception, out of line.

Small size increase to get better TX performance.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 2/2 grow/shrink: 8/0 up/down: 296/-125 (171)
Function                                     old     new   delta
__fl6_update_dst                               -     104    +104
rawv6_sendmsg                               2244    2284     +40
udpv6_sendmsg                               3013    3043     +30
tcp_v6_connect                              1514    1534     +20
cookie_v6_check                             1501    1519     +18
ip6_datagram_dst_update                      673     690     +17
inet6_sk_rebuild_header                      499     516     +17
inet6_csk_route_socket                       507     524     +17
inet6_csk_route_req                          343     360     +17
__pfx___fl6_update_dst                         -      16     +16
__pfx_fl6_update_dst                          16       -     -16
fl6_update_dst                               109       -    -109
Total: Before=22570304, After=22570475, chg +0.00%

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260128185548.3738781-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 70e9a576

include/net/ipv6.h

+13 −3
Original line number Diff line number Diff line
@@ -1174,10 +1174,20 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, int target, 


int ipv6_find_tlv(const struct sk_buff *skb, int offset, int type);



struct in6_addr *fl6_update_dst(struct flowi6 *fl6,

struct in6_addr *__fl6_update_dst(struct flowi6 *fl6,

				  const struct ipv6_txoptions *opt,

				  struct in6_addr *orig);



static inline struct in6_addr *

fl6_update_dst(struct flowi6 *fl6, const struct ipv6_txoptions *opt,

	       struct in6_addr *orig)

{

	if (likely(!opt))

		return NULL;



	return __fl6_update_dst(fl6, opt, orig);

}



/*

 *	socket options (ipv6_sockglue.c)

 */

net/ipv6/exthdrs.c

+7 −7
Original line number Diff line number Diff line
@@ -1336,21 +1336,21 @@ struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, 
EXPORT_SYMBOL_GPL(__ipv6_fixup_options);



/**

 * fl6_update_dst - update flowi destination address with info given

 * __fl6_update_dst - update flowi destination address with info given

 *                  by srcrt option, if any.

 *

 * @fl6: flowi6 for which daddr is to be updated

 * @opt: struct ipv6_txoptions in which to look for srcrt opt

 * @orig: copy of original daddr address if modified

 *

 * Returns NULL if no txoptions or no srcrt, otherwise returns orig

 * Return: NULL if no srcrt or invalid srcrt type, otherwise returns orig

 * and initial value of fl6->daddr set in orig

 */

struct in6_addr *fl6_update_dst(struct flowi6 *fl6,

struct in6_addr *__fl6_update_dst(struct flowi6 *fl6,

				  const struct ipv6_txoptions *opt,

				  struct in6_addr *orig)

{

	if (!opt || !opt->srcrt)

	if (!opt->srcrt)

		return NULL;



	*orig = fl6->daddr;
@@ -1374,4 +1374,4 @@ struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 


	return orig;

}

EXPORT_SYMBOL_GPL(fl6_update_dst);
 
EXPORT_SYMBOL_GPL(__fl6_update_dst);