Merge branch 'sch_sfq-derived-limit'

Octavian Purdila says:

====================
net_sched: sch_sfq: reject a derived limit of 1

Because sfq parameters can influence each other there can be
situations where although the user sets a limit of 2 it can be lowered
to 1:

$ tc qdisc add dev dummy0 handle 1: root sfq limit 2 flows 1 depth 1
$ tc qdisc show dev dummy0
qdisc sfq 1: dev dummy0 root refcnt 2 limit 1p quantum 1514b depth 1 divisor 1024

$ tc qdisc add dev dummy0 handle 1: root sfq limit 2 flows 10 depth 1 divisor 1
$ tc qdisc show dev dummy0
qdisc sfq 2: root refcnt 2 limit 1p quantum 1514b depth 1 divisor 1

As a limit of 1 is invalid, this patch series moves the limit
validation to after all configuration changes have been done. To do
so, the configuration is done in a temporary work area then applied to
the internal state.

The patch series also adds new test cases.

v3:
 - remove a couple of unnecessary comments
 - rearrange local variables to use reverse Christmas tree style
   declaration order

v2: https://lore.kernel.org/all/20250402162750.1671155-1-tavip@google.com/
 - remove tmp struct and directly use local variables

v1: https://lore.kernel.org/all/20250328201634.3876474-1-tavip@google.com/
===================

Signed-off-by: David S. Miller <davem@davemloft.net>