github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-12 16:18:45 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

tcp: return a drop_reason from tcp_add_backlog()

Browse Source 
Part of a stack canary removal from tcp_v{4,6}_rcv().

Return a drop_reason instead of a boolean, so that we no longer
have to pass the address of a local variable.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-37 (-37)
Function                                     old     new   delta
tcp_v6_rcv                                  3133    3129      -4
tcp_v4_rcv                                  3206    3202      -4
tcp_add_backlog                             1281    1252     -29
Total: Before=25567186, After=25567149, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260409101147.1642967-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-04-09 10:11:47 +00:00 committed by Jakub Kicinski
parent 4431c239a3
commit f5148298b0
3 changed files with 12 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/tcp.h
View File

@ -1680,8 +1680,7 @@ static inline bool tcp_checksum_complete(struct sk_buff *skb)
__skb_checksum_complete(skb);
}
bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
enum skb_drop_reason *reason);
enum skb_drop_reason tcp_add_backlog(struct sock *sk, struct sk_buff *skb);
static inline int tcp_filter(struct sock *sk, struct sk_buff *skb,
enum skb_drop_reason *reason)

21
net/ipv4/tcp_ipv4.c
View File

@ -1900,8 +1900,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(tcp_v4_do_rcv);
bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
enum skb_drop_reason *reason)
enum skb_drop_reason tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
{
u32 tail_gso_size, tail_gso_segs;
struct skb_shared_info *shinfo;
@ -1929,10 +1928,9 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
if (unlikely(tcp_checksum_complete(skb))) {
bh_unlock_sock(sk);
trace_tcp_bad_csum(skb);
*reason = SKB_DROP_REASON_TCP_CSUM;
__TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
__TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
return true;
return SKB_DROP_REASON_TCP_CSUM;
}
/* Attempt coalescing to last skb in backlog, even if we are
@ -2006,7 +2004,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
__NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPBACKLOGCOALESCE);
kfree_skb_partial(skb, fragstolen);
return false;
return SKB_NOT_DROPPED_YET;
}
__skb_push(skb, hdrlen);
@ -2031,15 +2029,13 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
if (unlikely(err)) {
bh_unlock_sock(sk);
if (err == -ENOMEM) {
*reason = SKB_DROP_REASON_PFMEMALLOC;
__NET_INC_STATS(sock_net(sk), LINUX_MIB_PFMEMALLOCDROP);
} else {
*reason = SKB_DROP_REASON_SOCKET_BACKLOG;
__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
return SKB_DROP_REASON_PFMEMALLOC;
}
return true;
__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
return SKB_DROP_REASON_SOCKET_BACKLOG;
}
return false;
return SKB_NOT_DROPPED_YET;
}
static void tcp_v4_restore_cb(struct sk_buff *skb)
@ -2247,7 +2243,8 @@ int tcp_v4_rcv(struct sk_buff *skb)
if (!sock_owned_by_user(sk)) {
ret = tcp_v4_do_rcv(sk, skb);
} else {
if (tcp_add_backlog(sk, skb, &drop_reason))
drop_reason = tcp_add_backlog(sk, skb);
if (drop_reason)
goto discard_and_relse;
}
bh_unlock_sock(sk);

3
net/ipv6/tcp_ipv6.c
View File

@ -1877,7 +1877,8 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
if (!sock_owned_by_user(sk)) {
ret = tcp_v6_do_rcv(sk, skb);
} else {
if (tcp_add_backlog(sk, skb, &drop_reason))
drop_reason = tcp_add_backlog(sk, skb);
if (drop_reason)
goto discard_and_relse;
}
bh_unlock_sock(sk);