net/mlx5e: Fix page reclaim for dead peer hairpin

When adding a hairpin flow, a firmware-side send queue is created for
the peer net device, which claims some host memory pages for its
internal ring buffer. If the peer net device is removed/unbound before
the hairpin flow is deleted, then the send queue is not destroyed which
leads to a stack trace on pci device remove:

[ 748.005230] mlx5_core 0000:08:00.2: wait_func:1094:(pid 12985): MANAGE_PAGES(0x108) timeout. Will cause a leak of a command resource
[ 748.005231] mlx5_core 0000:08:00.2: reclaim_pages:514:(pid 12985): failed reclaiming pages: err -110
[ 748.001835] mlx5_core 0000:08:00.2: mlx5_reclaim_root_pages:653:(pid 12985): failed reclaiming pages (-110) for func id 0x0
[ 748.002171] ------------[ cut here ]------------
[ 748.001177] FW pages counter is 4 after reclaiming all pages
[ 748.001186] WARNING: CPU: 1 PID: 12985 at drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c:685 mlx5_reclaim_startup_pages+0x34b/0x460 [mlx5_core]                      [  +0.002771] Modules linked in: cls_flower mlx5_ib mlx5_core ptp pps_core act_mirred sch_ingress openvswitch nsh xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi rdma_cm ib_umad ib_ipoib iw_cm ib_cm ib_uverbs ib_core overlay fuse [last unloaded: pps_core]
[ 748.007225] CPU: 1 PID: 12985 Comm: tee Not tainted 5.12.0+ #1
[ 748.001376] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 748.002315] RIP: 0010:mlx5_reclaim_startup_pages+0x34b/0x460 [mlx5_core]
[ 748.001679] Code: 28 00 00 00 0f 85 22 01 00 00 48 81 c4 b0 00 00 00 31 c0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 c7 c7 40 cc 19 a1 e8 9f 71 0e e2 <0f> 0b e9 30 ff ff ff 48 c7 c7 a0 cc 19 a1 e8 8c 71 0e e2 0f 0b e9
[ 748.003781] RSP: 0018:ffff88815220faf8 EFLAGS: 00010286
[ 748.001149] RAX: 0000000000000000 RBX: ffff8881b4900280 RCX: 0000000000000000
[ 748.001445] RDX: 0000000000000027 RSI: 0000000000000004 RDI: ffffed102a441f51
[ 748.001614] RBP: 00000000000032b9 R08: 0000000000000001 R09: ffffed1054a15ee8
[ 748.001446] R10: ffff8882a50af73b R11: ffffed1054a15ee7 R12: fffffbfff07c1e30
[ 748.001447] R13: dffffc0000000000 R14: ffff8881b492cba8 R15: 0000000000000000
[ 748.001429] FS:  00007f58bd08b580(0000) GS:ffff8882a5080000(0000) knlGS:0000000000000000
[ 748.001695] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 748.001309] CR2: 000055a026351740 CR3: 00000001d3b48006 CR4: 0000000000370ea0
[ 748.001506] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 748.001483] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 748.001654] Call Trace:
[ 748.000576]  ? mlx5_satisfy_startup_pages+0x290/0x290 [mlx5_core]
[ 748.001416]  ? mlx5_cmd_teardown_hca+0xa2/0xd0 [mlx5_core]
[ 748.001354]  ? mlx5_cmd_init_hca+0x280/0x280 [mlx5_core]
[ 748.001203]  mlx5_function_teardown+0x30/0x60 [mlx5_core]
[ 748.001275]  mlx5_uninit_one+0xa7/0xc0 [mlx5_core]
[ 748.001200]  remove_one+0x5f/0xc0 [mlx5_core]
[ 748.001075]  pci_device_remove+0x9f/0x1d0
[ 748.000833]  device_release_driver_internal+0x1e0/0x490
[ 748.001207]  unbind_store+0x19f/0x200
[ 748.000942]  ? sysfs_file_ops+0x170/0x170
[ 748.001000]  kernfs_fop_write_iter+0x2bc/0x450
[ 748.000970]  new_sync_write+0x373/0x610
[ 748.001124]  ? new_sync_read+0x600/0x600
[ 748.001057]  ? lock_acquire+0x4d6/0x700
[ 748.000908]  ? lockdep_hardirqs_on_prepare+0x400/0x400
[ 748.001126]  ? fd_install+0x1c9/0x4d0
[ 748.000951]  vfs_write+0x4d0/0x800
[ 748.000804]  ksys_write+0xf9/0x1d0
[ 748.000868]  ? __x64_sys_read+0xb0/0xb0
[ 748.000811]  ? filp_open+0x50/0x50
[ 748.000919]  ? syscall_enter_from_user_mode+0x1d/0x50
[ 748.001223]  do_syscall_64+0x3f/0x80
[ 748.000892]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 748.001026] RIP: 0033:0x7f58bcfb22f7
[ 748.000944] Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[ 748.003925] RSP: 002b:00007fffd7f2aaa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 748.001732] RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f58bcfb22f7
[ 748.001426] RDX: 000000000000000d RSI: 00007fffd7f2abc0 RDI: 0000000000000003
[ 748.001746] RBP: 00007fffd7f2abc0 R08: 0000000000000000 R09: 0000000000000001
[ 748.001631] R10: 00000000000001b6 R11: 0000000000000246 R12: 000000000000000d
[ 748.001537] R13: 00005597ac2c24a0 R14: 000000000000000d R15: 00007f58bd084700
[ 748.001564] irq event stamp: 0
[ 748.000787] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[ 748.001399] hardirqs last disabled at (0): [<ffffffff813132cf>] copy_process+0x146f/0x5eb0
[ 748.001854] softirqs last  enabled at (0): [<ffffffff8131330e>] copy_process+0x14ae/0x5eb0
[ 748.013431] softirqs last disabled at (0): [<0000000000000000>] 0x0
[ 748.001492] ---[ end trace a6fabd773d1c51ae ]---

Fix by destroying the send queue of a hairpin peer net device that is
being removed/unbound, which returns the allocated ring buffer pages to
the host.

Fixes: 4d8fcf21 ("net/mlx5e: Avoid unbounded peer devices when unpairing TC hairpin rules")
Signed-off-by: Dima Chumak <dchumak@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -4765,7 +4765,7 @@ static void mlx5e_tc_hairpin_update_dead_peer(struct mlx5e_priv *priv,
 	list_for_each_entry_safe(hpe, tmp, &init_wait_list, dead_peer_wait_list) {
 		wait_for_completion(&hpe->res_ready);
 		if (!IS_ERR_OR_NULL(hpe->hp) && hpe->peer_vhca_id == peer_vhca_id)
-			hpe->hp->pair->peer_gone = true;
+			mlx5_core_hairpin_clear_dead_peer(hpe->hp->pair);
 
 		mlx5e_hairpin_put(priv, hpe);
 	}

drivers/net/ethernet/mellanox/mlx5/core/transobj.c

@@ -424,6 +424,15 @@ static int mlx5_hairpin_pair_queues(struct mlx5_hairpin *hp)
 	return err;
 }
 
+static void mlx5_hairpin_unpair_peer_sq(struct mlx5_hairpin *hp)
+{
+	int i;
+
+	for (i = 0; i < hp->num_channels; i++)
+		mlx5_hairpin_modify_sq(hp->peer_mdev, hp->sqn[i], MLX5_SQC_STATE_RDY,
+				       MLX5_SQC_STATE_RST, 0, 0);
+}
+
 static void mlx5_hairpin_unpair_queues(struct mlx5_hairpin *hp)
 {
 	int i;
@@ -432,13 +441,9 @@ static void mlx5_hairpin_unpair_queues(struct mlx5_hairpin *hp)
 	for (i = 0; i < hp->num_channels; i++)
 		mlx5_hairpin_modify_rq(hp->func_mdev, hp->rqn[i], MLX5_RQC_STATE_RDY,
 				       MLX5_RQC_STATE_RST, 0, 0);
-
 	/* unset peer SQs */
-	if (hp->peer_gone)
-		return;
-	for (i = 0; i < hp->num_channels; i++)
-		mlx5_hairpin_modify_sq(hp->peer_mdev, hp->sqn[i], MLX5_SQC_STATE_RDY,
-				       MLX5_SQC_STATE_RST, 0, 0);
+	if (!hp->peer_gone)
+		mlx5_hairpin_unpair_peer_sq(hp);
 }
 
 struct mlx5_hairpin *
@@ -485,3 +490,16 @@ void mlx5_core_hairpin_destroy(struct mlx5_hairpin *hp)
 	mlx5_hairpin_destroy_queues(hp);
 	kfree(hp);
 }
+
+void mlx5_core_hairpin_clear_dead_peer(struct mlx5_hairpin *hp)
+{
+	int i;
+
+	mlx5_hairpin_unpair_peer_sq(hp);
+
+	/* destroy peer SQ */
+	for (i = 0; i < hp->num_channels; i++)
+		mlx5_core_destroy_sq(hp->peer_mdev, hp->sqn[i]);
+
+	hp->peer_gone = true;
+}

include/linux/mlx5/transobj.h

@@ -85,4 +85,5 @@ mlx5_core_hairpin_create(struct mlx5_core_dev *func_mdev,
 			 struct mlx5_hairpin_params *params);
 
 void mlx5_core_hairpin_destroy(struct mlx5_hairpin *pair);
+void mlx5_core_hairpin_clear_dead_peer(struct mlx5_hairpin *hp);
 #endif /* __TRANSOBJ_H__ */