Revert "bpf, sockmap: Prevent lock inversion deadlock in map delete elem"

This reverts commit ff91059932.

This check is no longer needed. BPF programs attached to tracepoints are
now rejected by the verifier when they attempt to delete from a
sockmap/sockhash maps.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240527-sockmap-verify-deletes-v1-2-944b372f2101@cloudflare.com

net/core/sock_map.c

@@ -423,9 +423,6 @@ static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test,
 	struct sock *sk;
 	int err = 0;
 
-	if (irqs_disabled())
-		return -EOPNOTSUPP; /* locks here are hardirq-unsafe */
-
 	spin_lock_bh(&stab->lock);
 	sk = *psk;
 	if (!sk_test || sk_test == sk)
@@ -948,9 +945,6 @@ static long sock_hash_delete_elem(struct bpf_map *map, void *key)
 	struct bpf_shtab_elem *elem;
 	int ret = -ENOENT;
 
-	if (irqs_disabled())
-		return -EOPNOTSUPP; /* locks here are hardirq-unsafe */
-
 	hash = sock_hash_bucket_hash(key, key_size);
 	bucket = sock_hash_select_bucket(htab, hash);