netfilter: nf_tables: Fix percpu address space issues in nf_tables_api.c

Compiling nf_tables_api.c results in several sparse warnings:

nf_tables_api.c:2077:31: warning: incorrect type in return expression (different address spaces)
nf_tables_api.c:2080:31: warning: incorrect type in return expression (different address spaces)
nf_tables_api.c:2084:31: warning: incorrect type in return expression (different address spaces)

nf_tables_api.c:2740:23: warning: incorrect type in assignment (different address spaces)
nf_tables_api.c:2752:38: warning: incorrect type in assignment (different address spaces)
nf_tables_api.c:2798:21: warning: incorrect type in argument 1 (different address spaces)

Use {ERR_PTR,IS_ERR,PTR_ERR}_PCPU() macros when crossing between generic
and percpu address spaces and add __percpu annotation to *stats pointer
to fix these warnings.

Found by GCC's named address space checks.

There were no changes in the resulting object files.

Signed-off-by: Uros Bizjak <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: Pablo Neira Ayuso <[e-mail]>

net/netfilter/nf_tables_api.c

···
 	err = nla_parse_nested_deprecated(tb, NFTA_COUNTER_MAX, attr,
 					  nft_counter_policy, NULL);
 	if (err < 0)
-		return ERR_PTR(err);
+		return ERR_PTR_PCPU(err);
 
 	if (!tb[NFTA_COUNTER_BYTES] || !tb[NFTA_COUNTER_PACKETS])
-		return ERR_PTR(-EINVAL);
+		return ERR_PTR_PCPU(-EINVAL);
 
 	newstats = netdev_alloc_pcpu_stats(struct nft_stats);
 	if (newstats == NULL)
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR_PCPU(-ENOMEM);
 
 	/* Restore old counters on this cpu, no problem. Per-cpu statistics
 	 * are not exposed to userspace.
···
 
 		if (nla[NFTA_CHAIN_COUNTERS]) {
 			stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);
-			if (IS_ERR(stats)) {
+			if (IS_ERR_PCPU(stats)) {
 				nft_chain_release_hook(&hook);
 				kfree(basechain);
-				return PTR_ERR(stats);
+				return PTR_ERR_PCPU(stats);
 			}
 			rcu_assign_pointer(basechain->stats, stats);
 		}
···
 	struct nft_table *table = ctx->table;
 	struct nft_chain *chain = ctx->chain;
 	struct nft_chain_hook hook = {};
-	struct nft_stats *stats = NULL;
+	struct nft_stats __percpu *stats = NULL;
 	struct nft_hook *h, *next;
 	struct nf_hook_ops *ops;
 	struct nft_trans *trans;
···
 		}
 
 		stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);
-		if (IS_ERR(stats)) {
-			err = PTR_ERR(stats);
+		if (IS_ERR_PCPU(stats)) {
+			err = PTR_ERR_PCPU(stats);
 			goto err_hooks;
 		}
 	}