idpf: return 0 size for RSS key if not supported

Returning -EOPNOTSUPP from function returning u32 is leading to
cast and invalid size value as a result.

-EOPNOTSUPP as a size probably will lead to allocation fail.

Command: ethtool -x eth0
It is visible on all devices that don't have RSS caps set.

[  136.615917] Call Trace:
[  136.615921]  <TASK>
[  136.615927]  ? __warn+0x89/0x130
[  136.615942]  ? __alloc_frozen_pages_noprof+0x322/0x330
[  136.615953]  ? report_bug+0x164/0x190
[  136.615968]  ? handle_bug+0x58/0x90
[  136.615979]  ? exc_invalid_op+0x17/0x70
[  136.615987]  ? asm_exc_invalid_op+0x1a/0x20
[  136.616001]  ? rss_prepare_get.constprop.0+0xb9/0x170
[  136.616016]  ? __alloc_frozen_pages_noprof+0x322/0x330
[  136.616028]  __alloc_pages_noprof+0xe/0x20
[  136.616038]  ___kmalloc_large_node+0x80/0x110
[  136.616072]  __kmalloc_large_node_noprof+0x1d/0xa0
[  136.616081]  __kmalloc_noprof+0x32c/0x4c0
[  136.616098]  ? rss_prepare_get.constprop.0+0xb9/0x170
[  136.616105]  rss_prepare_get.constprop.0+0xb9/0x170
[  136.616114]  ethnl_default_doit+0x107/0x3d0
[  136.616131]  genl_family_rcv_msg_doit+0x100/0x160
[  136.616147]  genl_rcv_msg+0x1b8/0x2c0
[  136.616156]  ? __pfx_ethnl_default_doit+0x10/0x10
[  136.616168]  ? __pfx_genl_rcv_msg+0x10/0x10
[  136.616176]  netlink_rcv_skb+0x58/0x110
[  136.616186]  genl_rcv+0x28/0x40
[  136.616195]  netlink_unicast+0x19b/0x290
[  136.616206]  netlink_sendmsg+0x222/0x490
[  136.616215]  __sys_sendto+0x1fd/0x210
[  136.616233]  __x64_sys_sendto+0x24/0x30
[  136.616242]  do_syscall_64+0x82/0x160
[  136.616252]  ? __sys_recvmsg+0x83/0xe0
[  136.616265]  ? syscall_exit_to_user_mode+0x10/0x210
[  136.616275]  ? do_syscall_64+0x8e/0x160
[  136.616282]  ? __count_memcg_events+0xa1/0x130
[  136.616295]  ? count_memcg_events.constprop.0+0x1a/0x30
[  136.616306]  ? handle_mm_fault+0xae/0x2d0
[  136.616319]  ? do_user_addr_fault+0x379/0x670
[  136.616328]  ? clear_bhb_loop+0x45/0xa0
[  136.616340]  ? clear_bhb_loop+0x45/0xa0
[  136.616349]  ? clear_bhb_loop+0x45/0xa0
[  136.616359]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  136.616369] RIP: 0033:0x7fd30ba7b047
[  136.616376] Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 80 3d bd d5 0c 00 00 41 89 ca 74 10 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 71 c3 55 48 83 ec 30 44 89 4c 24 2c 4c 89 44
[  136.616381] RSP: 002b:00007ffde1796d68 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
[  136.616388] RAX: ffffffffffffffda RBX: 000055d7bd89f2a0 RCX: 00007fd30ba7b047
[  136.616392] RDX: 0000000000000028 RSI: 000055d7bd89f3b0 RDI: 0000000000000003
[  136.616396] RBP: 00007ffde1796e10 R08: 00007fd30bb4e200 R09: 000000000000000c
[  136.616399] R10: 0000000000000000 R11: 0000000000000202 R12: 000055d7bd89f340
[  136.616403] R13: 000055d7bd89f3b0 R14: 000055d78943f200 R15: 0000000000000000

Fixes: 02cbfba ("idpf: add ethtool callbacks")
Reviewed-by: Ahmed Zaki <[email protected]>
Signed-off-by: Michal Swiatkowski <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Tested-by: Samuel Salin <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: Michal Swiatkowski

drivers/net/ethernet/intel/idpf/idpf_ethtool.c

@@ -47,7 +47,7 @@ static u32 idpf_get_rxfh_key_size(struct net_device *netdev)
 	struct idpf_vport_user_config_data *user_config;
 
 	if (!idpf_is_cap_ena_all(np->adapter, IDPF_RSS_CAPS, IDPF_CAP_RSS))
-		return -EOPNOTSUPP;
+		return 0;
 
 	user_config = &np->adapter->vport_config[np->vport_idx]->user_config;
 
@@ -66,7 +66,7 @@ static u32 idpf_get_rxfh_indir_size(struct net_device *netdev)
 	struct idpf_vport_user_config_data *user_config;
 
 	if (!idpf_is_cap_ena_all(np->adapter, IDPF_RSS_CAPS, IDPF_CAP_RSS))
-		return -EOPNOTSUPP;
+		return 0;
 
 	user_config = &np->adapter->vport_config[np->vport_idx]->user_config;