[PATCH 23/38] cls_api: Convert tcf_net to XArray

[Matthew Wilcox]

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

This module doesn't use the allocating functionality; convert it to a
plain XArray instead of an allocating one.  I've left struct tcf_net
in place in case more objects are added to it in future, although
it now only contains an XArray.  We don't need to call xa_destroy()
if the array is empty, so I've removed the contents of tcf_net_exit()
-- if it can be called with entries still in place, then it shoud call
xa_destroy() instead.

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 net/sched/cls_api.c | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index e0d8b456e9f5..8392a7ef0ed4 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -19,7 +19,7 @@
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
-#include <linux/idr.h>
+#include <linux/xarray.h>
 #include <linux/rhashtable.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
@@ -777,8 +777,7 @@ tcf_chain0_head_change_cb_del(struct tcf_block *block,
 }
 
 struct tcf_net {
-       spinlock_t idr_lock; /* Protects idr */
-       struct idr idr;
+       struct xarray blocks;
 };
 
 static unsigned int tcf_net_id;
@@ -787,25 +786,15 @@ static int tcf_block_insert(struct tcf_block *block, 
struct net *net,
                            struct netlink_ext_ack *extack)
 {
        struct tcf_net *tn = net_generic(net, tcf_net_id);
-       int err;
-
-       idr_preload(GFP_KERNEL);
-       spin_lock(&tn->idr_lock);
-       err = idr_alloc_u32(&tn->idr, block, &block->index, block->index,
-                           GFP_NOWAIT);
-       spin_unlock(&tn->idr_lock);
-       idr_preload_end();
 
-       return err;
+       return xa_insert(&tn->blocks, block->index, block, GFP_KERNEL);
 }
 
 static void tcf_block_remove(struct tcf_block *block, struct net *net)
 {
        struct tcf_net *tn = net_generic(net, tcf_net_id);
 
-       spin_lock(&tn->idr_lock);
-       idr_remove(&tn->idr, block->index);
-       spin_unlock(&tn->idr_lock);
+       xa_erase(&tn->blocks, block->index);
 }
 
 static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
@@ -839,7 +828,7 @@ static struct tcf_block *tcf_block_lookup(struct net *net, 
u32 block_index)
 {
        struct tcf_net *tn = net_generic(net, tcf_net_id);
 
-       return idr_find(&tn->idr, block_index);
+       return xa_load(&tn->blocks, block_index);
 }
 
 static struct tcf_block *tcf_block_refcnt_get(struct net *net, u32 block_index)
@@ -3164,16 +3153,12 @@ static __net_init int tcf_net_init(struct net *net)
 {
        struct tcf_net *tn = net_generic(net, tcf_net_id);
 
-       spin_lock_init(&tn->idr_lock);
-       idr_init(&tn->idr);
+       xa_init(&tn->blocks);
        return 0;
 }
 
 static void __net_exit tcf_net_exit(struct net *net)
 {
-       struct tcf_net *tn = net_generic(net, tcf_net_id);
-
-       idr_destroy(&tn->idr);
 }
 
 static struct pernet_operations tcf_net_ops = {
-- 
2.23.0.rc1