[PATCH] net/sched: taprio: Drop unnecessary NULL check after container_of

From: Guenter Roeck
Date: Tue May 11 2021 - 16:54:57 EST


The rcu_head pointer passed to taprio_free_sched_cb is never NULL.
That means that the result of container_of() operations on it is also
never NULL, even though rcu_head is the first element of the structure
embedding it. On top of that, it is misleading to perform a NULL check
on the result of container_of() because the position of the contained
element could change, which would make the check invalid. Remove the
unnecessary NULL check.

This change was made automatically with the following Coccinelle script.

@@
type t;
identifier v;
statement s;
@@

<+...
(
t v = container_of(...);
|
v = container_of(...);
)
...
when != v
- if (\( !v \| v == NULL \) ) s
...+>

Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
net/sched/sch_taprio.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 5c91df52b8c2..71e8a7a84841 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -114,9 +114,6 @@ static void taprio_free_sched_cb(struct rcu_head *head)
struct sched_gate_list *sched = container_of(head, struct sched_gate_list, rcu);
struct sched_entry *entry, *n;

- if (!sched)
- return;
-
list_for_each_entry_safe(entry, n, &sched->entries, list) {
list_del(&entry->list);
kfree(entry);
--
2.25.1