netfilter: nf_tables: bogus ENOENT when destroying element which does not exist

JIRA: https://issues.redhat.com/browse/RHEL-21443
Upstream Status: commit a7d5a95

commit a7d5a95
Author: Pablo Neira Ayuso <pablo@netfilter.org>
Date:   Mon Nov 13 20:34:56 2023 +0100

    netfilter: nf_tables: bogus ENOENT when destroying element which does not exist

    destroy element command bogusly reports ENOENT in case a set element
    does not exist. ENOENT errors are skipped, however, err is still set
    and propagated to userspace.

     # nft destroy element ip raw BLACKLIST { 1.2.3.4 }
     Error: Could not process rule: No such file or directory
     destroy element ip raw BLACKLIST { 1.2.3.4 }
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    Fixes: f80a612 ("netfilter: nf_tables: add support to destroy operation")
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Signed-off-by: Florian Westphal <fwestpha@redhat.com>

Author: fw-strlen

net/netfilter/nf_tables_api.c

@@ -7012,10 +7012,11 @@ static int nf_tables_delsetelem(struct sk_buff *skb,
 
 		if (err < 0) {
 			NL_SET_BAD_ATTR(extack, attr);
-			break;
+			return err;
 		}
 	}
-	return err;
+
+	return 0;
 }
 
 /*