net/mlx5: CT: Change idr to xarray to protect parallel tuple id allocation

After allowing parallel tuple insertion, we get the following trace:

[ 5505.142249] ------------[ cut here ]------------
[ 5505.148155] WARNING: CPU: 21 PID: 13313 at lib/radix-tree.c:581 delete_node+0x16c/0x180
[ 5505.295553] CPU: 21 PID: 13313 Comm: kworker/u50:22 Tainted: G           OE     5.6.0+ #78
[ 5505.304824] Hardware name: Supermicro Super Server/X10DRT-P, BIOS 2.0b 03/30/2017
[ 5505.313740] Workqueue: nf_flow_table_offload flow_offload_work_handler [nf_flow_table]
[ 5505.323257] RIP: 0010:delete_node+0x16c/0x180
[ 5505.349862] RSP: 0018:ffffb19184eb7b30 EFLAGS: 00010282
[ 5505.356785] RAX: 0000000000000000 RBX: ffff904ac95b86d8 RCX: ffff904b6f938838
[ 5505.365190] RDX: 0000000000000000 RSI: ffff904ac954b908 RDI: ffff904ac954b920
[ 5505.373628] RBP: ffff904b4ac13060 R08: 0000000000000001 R09: 0000000000000000
[ 5505.382155] R10: 0000000000000000 R11: 0000000000000040 R12: 0000000000000000
[ 5505.390527] R13: ffffb19184eb7bfc R14: ffff904b6bef5800 R15: ffff90482c1203c0
[ 5505.399246] FS:  0000000000000000(0000) GS:ffff904c2fc80000(0000) knlGS:0000000000000000
[ 5505.408621] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5505.415739] CR2: 00007f5d27006010 CR3: 0000000058c10006 CR4: 00000000001626e0
[ 5505.424547] Call Trace:
[ 5505.428429]  idr_alloc_u32+0x7b/0xc0
[ 5505.433803]  mlx5_tc_ct_entry_add_rule+0xbf/0x950 [mlx5_core]
[ 5505.441354]  ? mlx5_fc_create+0x23c/0x370 [mlx5_core]
[ 5505.448225]  mlx5_tc_ct_block_flow_offload+0x874/0x10b0 [mlx5_core]
[ 5505.456278]  ? mlx5_tc_ct_block_flow_offload+0x63d/0x10b0 [mlx5_core]
[ 5505.464532]  nf_flow_offload_tuple.isra.21+0xc5/0x140 [nf_flow_table]
[ 5505.472286]  ? __kmalloc+0x217/0x2f0
[ 5505.477093]  ? flow_rule_alloc+0x1c/0x30
[ 5505.482117]  flow_offload_work_handler+0x1d0/0x290 [nf_flow_table]
[ 5505.489674]  ? process_one_work+0x17c/0x580
[ 5505.494922]  process_one_work+0x202/0x580
[ 5505.500082]  ? process_one_work+0x17c/0x580
[ 5505.505696]  worker_thread+0x4c/0x3f0
[ 5505.510458]  kthread+0x103/0x140
[ 5505.514989]  ? process_one_work+0x580/0x580
[ 5505.520616]  ? kthread_bind+0x10/0x10
[ 5505.525837]  ret_from_fork+0x3a/0x50
[ 5505.570841] ---[ end trace 07995de9c56d6831 ]---

This happens from parallel deletes/adds to idr, as idr isn't protected.
Fix that by using xarray as the tuple_ids allocator instead of idr.

Fixes: 7da182a ("netfilter: flowtable: Use work entry per offload command")
Reviewed-by: Roi Dayan <[email protected]>
Signed-off-by: Paul Blakey <[email protected]>
Reviewed-by: Oz Shlomo <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>

Author: Paul Blakey

drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c

@@ -12,6 +12,7 @@
 #include <net/flow_offload.h>
 #include <net/netfilter/nf_flow_table.h>
 #include <linux/workqueue.h>
+#include <linux/xarray.h>
 
 #include "esw/chains.h"
 #include "en/tc_ct.h"
@@ -35,7 +36,7 @@ struct mlx5_tc_ct_priv {
 	struct mlx5_eswitch *esw;
 	const struct net_device *netdev;
 	struct idr fte_ids;
-	struct idr tuple_ids;
+	struct xarray tuple_ids;
 	struct rhashtable zone_ht;
 	struct mlx5_flow_table *ct;
 	struct mlx5_flow_table *ct_nat;
@@ -238,7 +239,7 @@ mlx5_tc_ct_entry_del_rule(struct mlx5_tc_ct_priv *ct_priv,
 
 	mlx5_eswitch_del_offloaded_rule(esw, zone_rule->rule, attr);
 	mlx5_modify_header_dealloc(esw->dev, attr->modify_hdr);
-	idr_remove(&ct_priv->tuple_ids, zone_rule->tupleid);
+	xa_erase(&ct_priv->tuple_ids, zone_rule->tupleid);
 }
 
 static void
@@ -483,7 +484,7 @@ mlx5_tc_ct_entry_add_rule(struct mlx5_tc_ct_priv *ct_priv,
 	struct mlx5_esw_flow_attr *attr = &zone_rule->attr;
 	struct mlx5_eswitch *esw = ct_priv->esw;
 	struct mlx5_flow_spec *spec = NULL;
-	u32 tupleid = 1;
+	u32 tupleid;
 	int err;
 
 	zone_rule->nat = nat;
@@ -493,12 +494,12 @@ mlx5_tc_ct_entry_add_rule(struct mlx5_tc_ct_priv *ct_priv,
 		return -ENOMEM;
 
 	/* Get tuple unique id */
-	err = idr_alloc_u32(&ct_priv->tuple_ids, zone_rule, &tupleid,
-			    TUPLE_ID_MAX, GFP_KERNEL);
+	err = xa_alloc(&ct_priv->tuple_ids, &tupleid, zone_rule,
+		       XA_LIMIT(1, TUPLE_ID_MAX), GFP_KERNEL);
 	if (err) {
 		netdev_warn(ct_priv->netdev,
 			    "Failed to allocate tuple id, err: %d\n", err);
-		goto err_idr_alloc;
+		goto err_xa_alloc;
 	}
 	zone_rule->tupleid = tupleid;
 
@@ -539,8 +540,8 @@ mlx5_tc_ct_entry_add_rule(struct mlx5_tc_ct_priv *ct_priv,
 err_rule:
 	mlx5_modify_header_dealloc(esw->dev, attr->modify_hdr);
 err_mod_hdr:
-	idr_remove(&ct_priv->tuple_ids, zone_rule->tupleid);
-err_idr_alloc:
+	xa_erase(&ct_priv->tuple_ids, zone_rule->tupleid);
+err_xa_alloc:
 	kfree(spec);
 	return err;
 }
@@ -1299,7 +1300,7 @@ mlx5_tc_ct_init(struct mlx5_rep_uplink_priv *uplink_priv)
 	}
 
 	idr_init(&ct_priv->fte_ids);
-	idr_init(&ct_priv->tuple_ids);
+	xa_init_flags(&ct_priv->tuple_ids, XA_FLAGS_ALLOC1);
 	mutex_init(&ct_priv->control_lock);
 	rhashtable_init(&ct_priv->zone_ht, &zone_params);
 
@@ -1334,7 +1335,7 @@ mlx5_tc_ct_clean(struct mlx5_rep_uplink_priv *uplink_priv)
 
 	rhashtable_destroy(&ct_priv->zone_ht);
 	mutex_destroy(&ct_priv->control_lock);
-	idr_destroy(&ct_priv->tuple_ids);
+	xa_destroy(&ct_priv->tuple_ids);
 	idr_destroy(&ct_priv->fte_ids);
 	kfree(ct_priv);
 
@@ -1352,7 +1353,7 @@ mlx5e_tc_ct_restore_flow(struct mlx5_rep_uplink_priv *uplink_priv,
 	if (!ct_priv || !tupleid)
 		return true;
 
-	zone_rule = idr_find(&ct_priv->tuple_ids, tupleid);
+	zone_rule = xa_load(&ct_priv->tuple_ids, tupleid);
 	if (!zone_rule)
 		return false;