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Date: Tue, 20 Aug 2019 15:32:50 -0700
From: Matthew Wilcox <willy@...radead.org>
To: netdev@...r.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Subject: [PATCH 29/38] cls_flower: Convert handle_idr to XArray
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Inline __fl_get() into fl_get(). Use the RCU lock explicitly for
lookups and walks instead of relying on RTNL. The xa_lock protects us,
but remains nested under the RTNL for now.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
net/sched/cls_flower.c | 54 ++++++++++++++++++++----------------------
1 file changed, 26 insertions(+), 28 deletions(-)
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 054123742e32..54026c9e9b05 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -91,7 +91,7 @@ struct cls_fl_head {
struct list_head masks;
struct list_head hw_filters;
struct rcu_work rwork;
- struct idr handle_idr;
+ struct xarray filters;
};
struct cls_fl_filter {
@@ -334,7 +334,7 @@ static int fl_init(struct tcf_proto *tp)
INIT_LIST_HEAD_RCU(&head->masks);
INIT_LIST_HEAD(&head->hw_filters);
rcu_assign_pointer(tp->root, head);
- idr_init(&head->handle_idr);
+ xa_init_flags(&head->filters, XA_FLAGS_ALLOC1);
return rhashtable_init(&head->ht, &mask_ht_params);
}
@@ -530,19 +530,6 @@ static void __fl_put(struct cls_fl_filter *f)
__fl_destroy_filter(f);
}
-static struct cls_fl_filter *__fl_get(struct cls_fl_head *head, u32 handle)
-{
- struct cls_fl_filter *f;
-
- rcu_read_lock();
- f = idr_find(&head->handle_idr, handle);
- if (f && !refcount_inc_not_zero(&f->refcnt))
- f = NULL;
- rcu_read_unlock();
-
- return f;
-}
-
static int __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f,
bool *last, bool rtnl_held,
struct netlink_ext_ack *extack)
@@ -560,7 +547,7 @@ static int __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f,
f->deleted = true;
rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
f->mask->filter_ht_params);
- idr_remove(&head->handle_idr, f->handle);
+ xa_erase(&head->filters, f->handle);
list_del_rcu(&f->list);
spin_unlock(&tp->lock);
@@ -599,7 +586,7 @@ static void fl_destroy(struct tcf_proto *tp, bool rtnl_held,
break;
}
}
- idr_destroy(&head->handle_idr);
+ xa_destroy(&head->filters);
__module_get(THIS_MODULE);
tcf_queue_work(&head->rwork, fl_destroy_sleepable);
@@ -615,8 +602,15 @@ static void fl_put(struct tcf_proto *tp, void *arg)
static void *fl_get(struct tcf_proto *tp, u32 handle)
{
struct cls_fl_head *head = fl_head_dereference(tp);
+ struct cls_fl_filter *f;
+
+ rcu_read_lock();
+ f = xa_load(&head->filters, handle);
+ if (f && !refcount_inc_not_zero(&f->refcnt))
+ f = NULL;
+ rcu_read_unlock();
- return __fl_get(head, handle);
+ return f;
}
static const struct nla_policy fl_policy[TCA_FLOWER_MAX + 1] = {
@@ -1663,7 +1657,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
rhashtable_remove_fast(&fold->mask->ht,
&fold->ht_node,
fold->mask->filter_ht_params);
- idr_replace(&head->handle_idr, fnew, fnew->handle);
+ xa_store(&head->filters, fnew->handle, fnew, 0);
list_replace_rcu(&fold->list, &fnew->list);
fold->deleted = true;
@@ -1681,8 +1675,9 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
} else {
if (handle) {
/* user specifies a handle and it doesn't exist */
- err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
- handle, GFP_ATOMIC);
+ fnew->handle = handle;
+ err = xa_insert(&head->filters, handle, fnew,
+ GFP_ATOMIC);
/* Filter with specified handle was concurrently
* inserted after initial check in cls_api. This is not
@@ -1690,18 +1685,16 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
* message flags. Returning EAGAIN will cause cls_api to
* try to update concurrently inserted rule.
*/
- if (err == -ENOSPC)
+ if (err == -EBUSY)
err = -EAGAIN;
} else {
- handle = 1;
- err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
- INT_MAX, GFP_ATOMIC);
+ err = xa_alloc(&head->filters, &fnew->handle, fnew,
+ xa_limit_31b, GFP_ATOMIC);
}
if (err)
goto errout_hw;
refcount_inc(&fnew->refcnt);
- fnew->handle = handle;
list_add_tail_rcu(&fnew->list, &fnew->mask->filters);
spin_unlock(&tp->lock);
}
@@ -1755,23 +1748,28 @@ static void fl_walk(struct tcf_proto *tp, struct tcf_walker *arg,
bool rtnl_held)
{
struct cls_fl_head *head = fl_head_dereference(tp);
- unsigned long id = arg->cookie, tmp;
+ unsigned long id;
struct cls_fl_filter *f;
arg->count = arg->skip;
- idr_for_each_entry_continue_ul(&head->handle_idr, f, tmp, id) {
+ rcu_read_lock();
+ xa_for_each_start(&head->filters, id, f, arg->cookie) {
/* don't return filters that are being deleted */
if (!refcount_inc_not_zero(&f->refcnt))
continue;
+ rcu_read_unlock();
if (arg->fn(tp, f, arg) < 0) {
__fl_put(f);
arg->stop = 1;
+ rcu_read_lock();
break;
}
__fl_put(f);
arg->count++;
+ rcu_read_lock();
}
+ rcu_read_unlock();
arg->cookie = id;
}
--
2.23.0.rc1
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