[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 <dada1@cosmosbay.com>
CC: Stephen Hemminger <shemminger@linux-foundation.org>
CC: John find <linux.kernel@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index a3366c3..9583639 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -244,7 +244,7 @@
struct sk_filter *sk_filter;
void *sk_protinfo;
struct timer_list sk_timer;
- struct timeval sk_stamp;
+ ktime_t sk_stamp;
struct socket *sk_socket;
void *sk_user_data;
struct page *sk_sndmsg_page;
@@ -1307,19 +1307,19 @@
static __inline__ void
sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
{
- struct timeval stamp;
+ ktime_t kt = skb->tstamp;
- skb_get_timestamp(skb, &stamp);
if (sock_flag(sk, SOCK_RCVTSTAMP)) {
+ struct timeval tv;
/* Race occurred between timestamp enabling and packet
receiving. Fill in the current time for now. */
- if (stamp.tv_sec == 0)
- do_gettimeofday(&stamp);
- skb_set_timestamp(skb, &stamp);
- put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP, sizeof(struct timeval),
- &stamp);
+ if (kt.tv64 == 0)
+ kt = ktime_get_real();
+ skb->tstamp = kt;
+ tv = ktime_to_timeval(kt);
+ put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP, sizeof(tv), &tv);
} else
- sk->sk_stamp = stamp;
+ sk->sk_stamp = kt;
}
/**