From: Jiri Pirko <j...@mellanox.com>

When tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK, parent is still passed
down but the value is never used. Compiler does not recognize it and
issues a warning. Silence it down initializing parent to 0.

Fixes: 7960d1daf278 ("net: sched: use block index as a handle instead of qdisc 
when block is shared")
Reported-by: David Miller <da...@davemloft.net>
Reported-by: Stephen Rothwell <s...@canb.auug.org.au>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
v1->v2:
- add comment about why the initialization to 0 is ok
- move the initialization into the if block to be near the comment
---
 net/sched/cls_api.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index e500d11da9cd..86d6e9d2cf00 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1317,6 +1317,13 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct 
netlink_callback *cb)
                block = tcf_block_lookup(net, tcm->tcm_block_index);
                if (!block)
                        goto out;
+               /* If we work with block index, q is NULL and parent value
+                * will never be used in the following code. The check
+                * in tcf_fill_node prevents it. However, compiler does not
+                * see that far, so set parent to zero to silence the warning
+                * about parent being uninitialized.
+                */
+               parent = 0;
        } else {
                const struct Qdisc_class_ops *cops;
                struct net_device *dev;
-- 
2.14.3

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