Re: RE: RE: [Intel-wired-lan] [PATCH iwl-next v3] igb: Retrieve Tx timestamp directly from interrupt for i210

[Sebastian Andrzej Siewior]

On 2026-02-05 10:37:05 [+0000], Loktionov, Aleksandr wrote:
> > 
> > How or where can it sleep?
> > 
> > Sebastian
> 
> igb_ptp_tx_hwtstamp() -> https://elixir.bootlin.com/linux/v6.19-rc5/C/ident/skb_tstamp_tx -> https://elixir.bootlin.com/linux/v6.19-rc5/C/ident/__skb_complete_tx_timestamp -> https://elixir.bootlin.com/linux/v6.19-rc5/C/ident/sock_queue_err_skb -> https://elixir.bootlin.com/linux/v6.19-rc5/C/ident/skb_queue_tail -> https://elixir.bootlin.com/linux/v6.19-rc5/source/net/core/skbuff.c#L4075 

Would you please quote an actual call chain that can be looked up and
not this where a line crosses 300 characters?

> spin_lock_irqsave(&wq_head->lock, flags);  <- RT mutex can sleep

Okay. So you are concerned about this spinlock_t, I see.
igb_tsync_interrupt() also invokes ptp_clock_event() which acquires
pps_event_time::tsevqs_lock. Why is this not a problem?

Sebastian