net: sched: don't set q pointer for shared blocks

net: sched: don't set q pointer for shared blocks

It is pointless to set block->q for block which are shared among
multiple qdiscs. So remove the assignment in that case. Do a bit of code
reshuffle to make block->index initialized at that point so we can use
tcf_block_shared() helper.

Reported-by: Cong Wang <[email protected]>
Fixes: 4861738775d7 ("net: sched: introduce shared filter blocks infrastructure")
Signed-off-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>