net: Clear mono_delivery_time bit in __skb_tstamp_tx()

In __skb_tstamp_tx(), it may clone the egress skb and queues the clone to
the sk_error_queue.  The outgoing skb may have the mono delivery_time
while the (rcv) timestamp is expected for the clone, so the
skb->mono_delivery_time bit needs to be cleared from the clone.

This patch adds the skb->mono_delivery_time clearing to the existing
__net_timestamp() and use it in __skb_tstamp_tx().
The __net_timestamp() fast path usage in dev.c is changed to directly
call ktime_get_real() since the mono_delivery_time bit is not set at
that point.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7e2d796..8e8a4af 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3981,6 +3981,7 @@ static inline void skb_get_new_timestampns(const struct sk_buff *skb,
 static inline void __net_timestamp(struct sk_buff *skb)
 {
        skb->tstamp = ktime_get_real();
+       skb->mono_delivery_time = 0;
 }
 
 static inline ktime_t net_timedelta(ktime_t t)

diff --git a/net/core/dev.c b/net/core/dev.c
index e128f26..5db2443 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2111,13 +2111,13 @@ static inline void net_timestamp_set(struct sk_buff *skb)
        skb->tstamp = 0;
        skb->mono_delivery_time = 0;
        if (static_branch_unlikely(&netstamp_needed_key))
-               __net_timestamp(skb);
+               skb->tstamp = ktime_get_real();
 }
 
 #define net_timestamp_check(COND, SKB)                         \
        if (static_branch_unlikely(&netstamp_needed_key)) {     \
                if ((COND) && !(SKB)->tstamp)                   \
-                       __net_timestamp(SKB);                   \
+                       (SKB)->tstamp = ktime_get_real();       \
        }                                                       \
 
 bool is_skb_forwardable(const struct net_device *dev, const struct sk_buff *skb)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9abb002..e508283 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4851,7 +4851,7 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
        if (hwtstamps)
                *skb_hwtstamps(skb) = *hwtstamps;
        else
-               skb->tstamp = ktime_get_real();
+               __net_timestamp(skb);
 
        __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
 }