From b7aa0bf70c4afb9e38be25f5c0922498d0f8684c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 19 Apr 2007 16:16:32 -0700 Subject: [NET]: convert network timestamps to ktime_t We currently use a special structure (struct skb_timeval) and plain 'struct timeval' to store packet timestamps in sk_buffs and struct sock. This has some drawbacks : - Fixed resolution of micro second. - Waste of space on 64bit platforms where sizeof(struct timeval)=16 I suggest using ktime_t that is a nice abstraction of high resolution time services, currently capable of nanosecond resolution. As sizeof(ktime_t) is 8 bytes, using ktime_t in 'struct sock' permits a 8 byte shrink of this structure on 64bit architectures. Some other structures also benefit from this size reduction (struct ipq in ipv4/ip_fragment.c, struct frag_queue in ipv6/reassembly.c, ...) Once this ktime infrastructure adopted, we can more easily provide nanosecond resolution on top of it. (ioctl SIOCGSTAMPNS and/or SO_TIMESTAMPNS/SCM_TIMESTAMPNS) Note : this patch includes a bug correction in compat_sock_get_timestamp() where a "err = 0;" was missing (so this syscall returned -ENOENT instead of 0) Signed-off-by: Eric Dumazet CC: Stephen Hemminger CC: John find Signed-off-by: David S. Miller --- net/core/sock.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 6d35d5775ba8..6ddb3664b993 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1512,8 +1512,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT; sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; - sk->sk_stamp.tv_sec = -1L; - sk->sk_stamp.tv_usec = -1L; + sk->sk_stamp = ktime_set(-1L, -1L); atomic_set(&sk->sk_refcnt, 1); } @@ -1554,14 +1553,17 @@ EXPORT_SYMBOL(release_sock); int sock_get_timestamp(struct sock *sk, struct timeval __user *userstamp) { + struct timeval tv; if (!sock_flag(sk, SOCK_TIMESTAMP)) sock_enable_timestamp(sk); - if (sk->sk_stamp.tv_sec == -1) + tv = ktime_to_timeval(sk->sk_stamp); + if (tv.tv_sec == -1) return -ENOENT; - if (sk->sk_stamp.tv_sec == 0) - do_gettimeofday(&sk->sk_stamp); - return copy_to_user(userstamp, &sk->sk_stamp, sizeof(struct timeval)) ? - -EFAULT : 0; + if (tv.tv_sec == 0) { + sk->sk_stamp = ktime_get_real(); + tv = ktime_to_timeval(sk->sk_stamp); + } + return copy_to_user(userstamp, &tv, sizeof(tv)) ? -EFAULT : 0; } EXPORT_SYMBOL(sock_get_timestamp); -- cgit v1.2.2