The new watchdog code triggers spurious watchdog resets on
NICs doing KTLS offload. Fix this by using the actual segments
consumed by the NIC driver's isc_txd_encap.
The issue is that rs_pending is updated using an estimate of
the descriptors that will be used for the current packet,
based on what bus_dma produced. However, NICs which support
ktls offload may do extra DMAs (and consume extra
descriptors) to derive crypto state when re-transmitting
TLS segments. This is the reason for allowing drivers to control
ift_pad. When this happens, the estimated rs_pending may undercount.
This may also happen if NIC drivers consume extra descriptors for
other reasons. (eg, hw errata handling on e1000)
Reviewed by: kbowling
Differential Revision: https://reviews.freebsd.org/D59321
Sponsored-by: Netflix
Andrew Gallatin
a5bb0fde67