On 4/18/2024 1:11 PM, Willem de Bruijn wrote: > Abhishek Chauhan (ABC) wrote: >> >> >> On 4/18/2024 11:47 AM, Willem de Bruijn wrote: >>> Abhishek Chauhan wrote: >>>> mono_delivery_time was added to check if skb->tstamp has delivery >>>> time in mono clock base (i.e. EDT) otherwise skb->tstamp has >>>> timestamp in ingress and delivery_time at egress. >>>> >>>> Renaming the bitfield from mono_delivery_time to tstamp_type is for >>>> extensibilty for other timestamps such as userspace timestamp >>>> (i.e. SO_TXTIME) set via sock opts. >>>> >>>> As we are renaming the mono_delivery_time to tstamp_type, it makes >>>> sense to start assigning tstamp_type based on enum defined >>>> in this commit. >>>> >>>> Earlier we used bool arg flag to check if the tstamp is mono in >>>> function skb_set_delivery_time, Now the signature of the functions >>>> accepts tstamp_type to distinguish between mono and real time. >>>> >>>> In future tstamp_type:1 can be extended to support userspace timestamp >>>> by increasing the bitfield. >>>> >>>> Link: https://lore.kernel.org/netdev/bc037db4-58bb-4861-ac31-a361a93841d3@xxxxxxxxx/ >>>> Signed-off-by: Abhishek Chauhan <quic_abchauha@xxxxxxxxxxx> >>> >>>> +/** >>>> + * tstamp_type:1 can take 2 values each >>>> + * represented by time base in skb >>>> + * 0x0 => real timestamp_type >>>> + * 0x1 => mono timestamp_type >>>> + */ >>>> +enum skb_tstamp_type { >>>> + SKB_CLOCK_REAL, /* Time base is skb is REALTIME */ >>>> + SKB_CLOCK_MONO, /* Time base is skb is MONOTONIC */ >>>> +}; >>>> + >>> >>> Can drop the comments. These names are self documenting. >> >> Noted! . I will take care of this >>> >>>> /** >>>> * DOC: Basic sk_buff geometry >>>> * >>>> @@ -819,7 +830,7 @@ typedef unsigned char *sk_buff_data_t; >>>> * @dst_pending_confirm: need to confirm neighbour >>>> * @decrypted: Decrypted SKB >>>> * @slow_gro: state present at GRO time, slower prepare step required >>>> - * @mono_delivery_time: When set, skb->tstamp has the >>>> + * @tstamp_type: When set, skb->tstamp has the >>>> * delivery_time in mono clock base (i.e. EDT). Otherwise, the >>>> * skb->tstamp has the (rcv) timestamp at ingress and >>>> * delivery_time at egress. >>> >>> Is this still correct? I think all egress does now annotate correctly >>> as SKB_CLOCK_MONO. So when not set it always is SKB_CLOCK_REAL. >>> >> That is correct. >> >>>> diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c >>>> index 61119d42b0fd..a062f88c47c3 100644 >>>> --- a/net/ipv4/tcp_output.c >>>> +++ b/net/ipv4/tcp_output.c >>>> @@ -1300,7 +1300,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, >>>> tp = tcp_sk(sk); >>>> prior_wstamp = tp->tcp_wstamp_ns; >>>> tp->tcp_wstamp_ns = max(tp->tcp_wstamp_ns, tp->tcp_clock_cache); >>>> - skb_set_delivery_time(skb, tp->tcp_wstamp_ns, true); >>>> + skb_set_delivery_time(skb, tp->tcp_wstamp_ns, CLOCK_MONOTONIC); >>> >>> Multiple references to CLOCK_MONOTONIC left >>> >> I think i took care of all the references. Apologies if i didn't understand your comment here. > > On closer read, there is a type issue here. > > skb_set_delivery_time takes a u8 tstamp_type. But it is often passed > a clockid_t, and that is also what the switch expects. > > But it does also get called with a tstamp_type in code like the > following: > > + u8 tstamp_type = skb->tstamp_type; > unsigned int hlen, ll_rs, mtu; > ktime_t tstamp = skb->tstamp; > struct ip_frag_state state; > @@ -82,7 +82,7 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk, > if (iter.frag) > ip_fraglist_prepare(skb, &iter); > > - skb_set_delivery_time(skb, tstamp, mono_delivery_time); > + skb_set_delivery_time(skb, tstamp, tstamp_type); > > So maybe we need two variants, one that takes a tstamp_type and one > that tames a clockid_t? > > The first can be simple, not switch needed. Just apply the two stores. I agree to what you are saying but clockid_t => points to int itself. For example :- void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc, clockid_t clockid) qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC); => sch_api.c qdisc_watchdog_init_clockid(&q->watchdog, sch, q->clockid); =>sch_etf.c (q->clockid is int) But i can change it to two new APIs one which accepts only clock_id (with switch) and other accepts u8 to directly store whatever is given.
