flowcache: restore a single flow_cache kmem_cache

It is not legal to create multiple kmem_cache having the same name.

flowcache can use a single kmem_cache, no need for a per netns
one.

Fixes: ca925cf1534e ("flowcache: Make flow cache name space aware")
Reported-by: Jakub Kicinski <moorray3@wp.pl>
Tested-by: Jakub Kicinski <moorray3@wp.pl>
Tested-by: Fan Du <fan.du@windriver.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 6 deletions

diff --git a/net/core/flow.c b/net/core/flow.c
index 344a184011fd..102f8ea2eb6e 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -45,6 +45,8 @@ struct flow_flush_info {
         struct completion               completion;
 };
 
+static struct kmem_cache *flow_cachep __read_mostly;
+
 #define flow_cache_hash_size(cache)     (1 << (cache)->hash_shift)
 #define FLOW_HASH_RND_PERIOD            (10 * 60 * HZ)
 
@@ -75,7 +77,7 @@ static void flow_entry_kill(struct flow_cache_entry *fle,
 {
         if (fle->object)
                 fle->object->ops->delete(fle->object);
-        kmem_cache_free(xfrm->flow_cachep, fle);
+        kmem_cache_free(flow_cachep, fle);
 }
 
 static void flow_cache_gc_task(struct work_struct *work)
@@ -230,7 +232,7 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
                 if (fcp->hash_count > fc->high_watermark)
                         flow_cache_shrink(fc, fcp);
 
-                fle = kmem_cache_alloc(net->xfrm.flow_cachep, GFP_ATOMIC);
+                fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
                 if (fle) {
                         fle->net = net;
                         fle->family = family;
@@ -435,10 +437,10 @@ int flow_cache_init(struct net *net)
         int i;
         struct flow_cache *fc = &net->xfrm.flow_cache_global;
 
-        /* Initialize per-net flow cache global variables here */
-        net->xfrm.flow_cachep = kmem_cache_create("flow_cache",
-                                        sizeof(struct flow_cache_entry),
-                                        0, SLAB_PANIC, NULL);
+        if (!flow_cachep)
+                flow_cachep = kmem_cache_create("flow_cache",
+                                                sizeof(struct flow_cache_entry),
+                                                0, SLAB_PANIC, NULL);
         spin_lock_init(&net->xfrm.flow_cache_gc_lock);
         INIT_LIST_HEAD(&net->xfrm.flow_cache_gc_list);
         INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task);