diff options
author | David Laight <David.Laight@ACULAB.COM> | 2023-12-06 13:44:20 +0000 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2023-12-08 10:44:42 -0800 |
commit | d9f28735af8781d9c8c6c406c2a102090644133d (patch) | |
tree | aff37910520f90b4c192c41a00fbde053c2d01e8 /include/net/ip.h | |
parent | 36b0bdb6d330fe0546fc7f97d93e8cfa57421ad9 (diff) |
Use READ/WRITE_ONCE() for IP local_port_range.
Commit 227b60f5102cd added a seqlock to ensure that the low and high
port numbers were always updated together.
This is overkill because the two 16bit port numbers can be held in
a u32 and read/written in a single instruction.
More recently 91d0b78c5177f added support for finer per-socket limits.
The user-supplied value is 'high << 16 | low' but they are held
separately and the socket options protected by the socket lock.
Use a u32 containing 'high << 16 | low' for both the 'net' and 'sk'
fields and use READ_ONCE()/WRITE_ONCE() to ensure both values are
always updated together.
Change (the now trival) inet_get_local_port_range() to a static inline
to optimise the calling code.
(In particular avoiding returning integers by reference.)
Signed-off-by: David Laight <david.laight@aculab.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Acked-by: Mat Martineau <martineau@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/4e505d4198e946a8be03fb1b4c3072b0@AcuMS.aculab.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net/ip.h')
-rw-r--r-- | include/net/ip.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/net/ip.h b/include/net/ip.h index 1fc4c8d69e33..b31be912489a 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -349,7 +349,13 @@ static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_o } \ } -void inet_get_local_port_range(const struct net *net, int *low, int *high); +static inline void inet_get_local_port_range(const struct net *net, int *low, int *high) +{ + u32 range = READ_ONCE(net->ipv4.ip_local_ports.range); + + *low = range & 0xffff; + *high = range >> 16; +} void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high); #ifdef CONFIG_SYSCTL |