[PATCH 24/38] cls_u32: Convert tc_u_common->handle_idr to XArray

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <wi...@infradead.org>

There are two structures called 'handle_idr' in this module, which is
most confusing.  Rename this one to ht_xa.  Leave the existing locking
alone, which means that we're covered by both the rtnl lock and the
XArray spinlock when accessing this XArray.

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 net/sched/cls_u32.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 8614088edd1b..18ef5f375976 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -86,7 +86,8 @@ struct tc_u_common {
        struct tc_u_hnode __rcu *hlist;
        void                    *ptr;
        int                     refcnt;
-       struct idr              handle_idr;
+       u32                     ht_next;
+       struct xarray           ht_xa;
        struct hlist_node       hnode;
        long                    knodes;
 };
@@ -305,8 +306,12 @@ static void *u32_get(struct tcf_proto *tp, u32 handle)
 /* Protected by rtnl lock */
 static u32 gen_new_htid(struct tc_u_common *tp_c, struct tc_u_hnode *ptr)
 {
-       int id = idr_alloc_cyclic(&tp_c->handle_idr, ptr, 1, 0x7FF, GFP_KERNEL);
-       if (id < 0)
+       int err;
+       u32 id;
+
+       err = xa_alloc_cyclic(&tp_c->ht_xa, &id, ptr, XA_LIMIT(0, 0x7ff),
+                       &tp_c->ht_next, GFP_KERNEL);
+       if (err < 0)
                return 0;
        return (id | 0x800U) << 20;
 }
@@ -371,8 +376,7 @@ static int u32_init(struct tcf_proto *tp)
                }
                tp_c->ptr = key;
                INIT_HLIST_NODE(&tp_c->hnode);
-               idr_init(&tp_c->handle_idr);
-
+               xa_init_flags(&tp_c->ht_xa, XA_FLAGS_ALLOC1);
                hlist_add_head(&tp_c->hnode, tc_u_hash(key));
        }
 
@@ -608,7 +612,7 @@ static int u32_destroy_hnode(struct tcf_proto *tp, struct 
tc_u_hnode *ht,
                if (phn == ht) {
                        u32_clear_hw_hnode(tp, ht, extack);
                        idr_destroy(&ht->handle_idr);
-                       idr_remove(&tp_c->handle_idr, ht->handle);
+                       xa_erase(&tp_c->ht_xa, ht->handle);
                        RCU_INIT_POINTER(*hn, ht->next);
                        kfree_rcu(ht, rcu);
                        return 0;
@@ -645,7 +649,6 @@ static void u32_destroy(struct tcf_proto *tp, bool 
rtnl_held,
                                kfree_rcu(ht, rcu);
                }
 
-               idr_destroy(&tp_c->handle_idr);
                kfree(tp_c);
        }
 
@@ -950,8 +953,7 @@ static int u32_change(struct net *net, struct sk_buff 
*in_skb,
                                return -ENOMEM;
                        }
                } else {
-                       err = idr_alloc_u32(&tp_c->handle_idr, ht, &handle,
-                                           handle, GFP_KERNEL);
+                       err = xa_insert(&tp_c->ht_xa, handle, ht, GFP_KERNEL);
                        if (err) {
                                kfree(ht);
                                return err;
@@ -966,7 +968,7 @@ static int u32_change(struct net *net, struct sk_buff 
*in_skb,
 
                err = u32_replace_hw_hnode(tp, ht, flags, extack);
                if (err) {
-                       idr_remove(&tp_c->handle_idr, handle);
+                       xa_erase(&tp_c->ht_xa, handle);
                        kfree(ht);
                        return err;
                }
-- 
2.23.0.rc1