K 10
svn:author
V 9
vmaffione
K 8
svn:date
V 27
2020-08-10T17:53:09.942100Z
K 7
svn:log
V 653
MFC r363378

iflib: initialize netmap with the correct number of descriptors

In case the network device has a RX or TX control queue, the correct
number of TX/RX descriptors is contained in the second entry of the
isc_ntxd (or isc_nrxd) array, rather than in the first entry.
This case is correctly handled by iflib_device_register() and
iflib_pseudo_register(), but not by iflib_netmap_attach().
If the first entry is larger than the second, this can result in a
panic. This change fixes the bug by introducing two helper functions
that also lead to some code simplification.

PR:     247647
Differential Revision:  https://reviews.freebsd.org/D25541

END