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 /net/ipv4/sysctl_net_ipv4.c | |
| 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 'net/ipv4/sysctl_net_ipv4.c')
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index f63a545a7374..7e4f16a7dcc1 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -50,26 +50,22 @@ static int tcp_plb_max_cong_thresh = 256; static int sysctl_tcp_low_latency __read_mostly; /* Update system visible IP port range */ -static void set_local_port_range(struct net *net, int range[2]) +static void set_local_port_range(struct net *net, unsigned int low, unsigned int high) { - bool same_parity = !((range[0] ^ range[1]) & 1); + bool same_parity = !((low ^ high) & 1); - write_seqlock_bh(&net->ipv4.ip_local_ports.lock); if (same_parity && !net->ipv4.ip_local_ports.warned) { net->ipv4.ip_local_ports.warned = true; pr_err_ratelimited("ip_local_port_range: prefer different parity for start/end values.\n"); } - net->ipv4.ip_local_ports.range[0] = range[0]; - net->ipv4.ip_local_ports.range[1] = range[1]; - write_sequnlock_bh(&net->ipv4.ip_local_ports.lock); + WRITE_ONCE(net->ipv4.ip_local_ports.range, high << 16 | low); } /* Validate changes from /proc interface. */ static int ipv4_local_port_range(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { - struct net *net = - container_of(table->data, struct net, ipv4.ip_local_ports.range); + struct net *net = table->data; int ret; int range[2]; struct ctl_table tmp = { @@ -93,7 +89,7 @@ static int ipv4_local_port_range(struct ctl_table *table, int write, (range[0] < READ_ONCE(net->ipv4.sysctl_ip_prot_sock))) ret = -EINVAL; else - set_local_port_range(net, range); + set_local_port_range(net, range[0], range[1]); } return ret; @@ -733,8 +729,8 @@ static struct ctl_table ipv4_net_table[] = { }, { .procname = "ip_local_port_range", - .maxlen = sizeof(init_net.ipv4.ip_local_ports.range), - .data = &init_net.ipv4.ip_local_ports.range, + .maxlen = 0, + .data = &init_net, .mode = 0644, .proc_handler = ipv4_local_port_range, }, |