path: root/net/compat.c
diff options
authorEric Dumazet <dada1@cosmosbay.com>2007-04-19 16:16:32 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:23:34 -0700
commitb7aa0bf70c4afb9e38be25f5c0922498d0f8684c (patch)
tree4bc9d61031f4eb40d73887d6bde09e7d6bf2b259 /net/compat.c
parent3927f2e8f9afa3424bb51ca81f7abac01ffd0005 (diff)
[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>
Diffstat (limited to 'net/compat.c')
1 files changed, 10 insertions, 5 deletions
diff --git a/net/compat.c b/net/compat.c
index 1f32866d09b7..17c2710b2b93 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -545,15 +545,20 @@ int compat_sock_get_timestamp(struct sock *sk, struct timeval __user *userstamp)
struct compat_timeval __user *ctv =
(struct compat_timeval __user*) userstamp;
int err = -ENOENT;
+ struct timeval tv;
if (!sock_flag(sk, SOCK_TIMESTAMP))
- if (sk->sk_stamp.tv_sec == -1)
+ tv = ktime_to_timeval(sk->sk_stamp);
+ if (tv.tv_sec == -1)
return err;
- if (sk->sk_stamp.tv_sec == 0)
- do_gettimeofday(&sk->sk_stamp);
- if (put_user(sk->sk_stamp.tv_sec, &ctv->tv_sec) ||
- put_user(sk->sk_stamp.tv_usec, &ctv->tv_usec))
+ if (tv.tv_sec == 0) {
+ sk->sk_stamp = ktime_get_real();
+ tv = ktime_to_timeval(sk->sk_stamp);
+ }
+ err = 0;
+ if (put_user(tv.tv_sec, &ctv->tv_sec) ||
+ put_user(tv.tv_usec, &ctv->tv_usec))
err = -EFAULT;
return err;

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