[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/linux/skbuff.h b/include/linux/skbuff.h
index 5992f65..f9441b5 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -27,6 +27,7 @@
#include <net/checksum.h>
#include <linux/rcupdate.h>
#include <linux/dmaengine.h>
+#include <linux/hrtimer.h>
#define HAVE_ALLOC_SKB /* For the drivers to know */
#define HAVE_ALIGNABLE_SKB /* Ditto 8) */
@@ -156,11 +157,6 @@
#define SKB_DATAREF_SHIFT 16
#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
-struct skb_timeval {
- u32 off_sec;
- u32 off_usec;
-};
-
enum {
SKB_FCLONE_UNAVAILABLE,
@@ -233,7 +229,7 @@
struct sk_buff *prev;
struct sock *sk;
- struct skb_timeval tstamp;
+ ktime_t tstamp;
struct net_device *dev;
int iif;
/* 4 byte hole on 64 bit*/
@@ -1365,26 +1361,14 @@
*/
static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *stamp)
{
- stamp->tv_sec = skb->tstamp.off_sec;
- stamp->tv_usec = skb->tstamp.off_usec;
+ *stamp = ktime_to_timeval(skb->tstamp);
}
-/**
- * skb_set_timestamp - set timestamp of a skb
- * @skb: skb to set stamp of
- * @stamp: pointer to struct timeval to get stamp from
- *
- * Timestamps are stored in the skb as offsets to a base timestamp.
- * This function converts a struct timeval to an offset and stores
- * it in the skb.
- */
-static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp)
+static inline void __net_timestamp(struct sk_buff *skb)
{
- skb->tstamp.off_sec = stamp->tv_sec;
- skb->tstamp.off_usec = stamp->tv_usec;
+ skb->tstamp = ktime_get_real();
}
-extern void __net_timestamp(struct sk_buff *skb);
extern __sum16 __skb_checksum_complete(struct sk_buff *skb);