ipv6: sr: static percpu allocation for hmac_ring

Current allocations are not NUMA aware, and lack proper
cleanup in case of error.

It is perfectly fine to use static per cpu allocations for 256 bytes
per cpu.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: David Lebrun <david.lebrun@uclouvain.be>
Acked-by: NDavid Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/seg6_hmac.c

@@ -45,7 +45,7 @@
 #include <net/seg6_hmac.h>
 #include <linux/random.h>
 
-static char * __percpu *hmac_ring;
+static DEFINE_PER_CPU(char [SEG6_HMAC_RING_SIZE], hmac_ring);
 
 static int seg6_hmac_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
 {
@@ -192,7 +192,7 @@ int seg6_hmac_compute(struct seg6_hmac_info *hinfo, struct ipv6_sr_hdr *hdr,
 	 */
 
 	local_bh_disable();
-	ring = *this_cpu_ptr(hmac_ring);
+	ring = this_cpu_ptr(hmac_ring);
 	off = ring;
 
 	/* source address */
@@ -353,27 +353,6 @@ int seg6_push_hmac(struct net *net, struct in6_addr *saddr,
 }
 EXPORT_SYMBOL(seg6_push_hmac);
 
-static int seg6_hmac_init_ring(void)
-{
-	int i;
-
-	hmac_ring = alloc_percpu(char *);
-
-	if (!hmac_ring)
-		return -ENOMEM;
-
-	for_each_possible_cpu(i) {
-		char *ring = kzalloc(SEG6_HMAC_RING_SIZE, GFP_KERNEL);
-
-		if (!ring)
-			return -ENOMEM;
-
-		*per_cpu_ptr(hmac_ring, i) = ring;
-	}
-
-	return 0;
-}
-
 static int seg6_hmac_init_algo(void)
 {
 	struct seg6_hmac_algo *algo;
@@ -422,16 +401,7 @@ static int seg6_hmac_init_algo(void)
 
 int __init seg6_hmac_init(void)
 {
-	int ret;
-
-	ret = seg6_hmac_init_ring();
-	if (ret < 0)
-		goto out;
-
-	ret = seg6_hmac_init_algo();
-
-out:
-	return ret;
+	return seg6_hmac_init_algo();
 }
 EXPORT_SYMBOL(seg6_hmac_init);
 
@@ -450,13 +420,6 @@ void seg6_hmac_exit(void)
 	struct seg6_hmac_algo *algo = NULL;
 	int i, alg_count, cpu;
 
-	for_each_possible_cpu(i) {
-		char *ring = *per_cpu_ptr(hmac_ring, i);
-
-		kfree(ring);
-	}
-	free_percpu(hmac_ring);
-
 	alg_count = sizeof(hmac_algos) / sizeof(struct seg6_hmac_algo);
 	for (i = 0; i < alg_count; i++) {
 		algo = &hmac_algos[i];