cxgb4: Fix error path in cxgb4_init_module

BUG: unable to handle kernel paging request at ffffffffa016a270
PGD 3270067 P4D 3270067 PUD 3271063 PMD 230bbd067 PTE 0
Oops: 0000 [#1
CPU: 0 PID: 6134 Comm: modprobe Not tainted 5.1.0+ #33
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:atomic_notifier_chain_register+0x24/0x60
Code: 1f 80 00 00 00 00 55 48 89 e5 41 54 49 89 f4 53 48 89 fb e8 ae b4 38 01 48 8b 53 38 48 8d 4b 38 48 85 d2 74 20 45 8b 44 24 10 <44> 3b 42 10 7e 08 eb 13 44 39 42 10 7c 0d 48 8d 4a 08 48 8b 52 08
RSP: 0018:ffffc90000e2bc60 EFLAGS: 00010086
RAX: 0000000000000292 RBX: ffffffff83467240 RCX: ffffffff83467278
RDX: ffffffffa016a260 RSI: ffffffff83752140 RDI: ffffffff83467240
RBP: ffffc90000e2bc70 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 00000000014fa61f R12: ffffffffa01c8260
R13: ffff888231091e00 R14: 0000000000000000 R15: ffffc90000e2be78
FS:  00007fbd8d7cd540(0000) GS:ffff888237a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa016a270 CR3: 000000022c7e3000 CR4: 00000000000006f0
Call Trace:
 register_inet6addr_notifier+0x13/0x20
 cxgb4_init_module+0x6c/0x1000 [cxgb4
 ? 0xffffffffa01d7000
 do_one_initcall+0x6c/0x3cc
 ? do_init_module+0x22/0x1f1
 ? rcu_read_lock_sched_held+0x97/0xb0
 ? kmem_cache_alloc_trace+0x325/0x3b0
 do_init_module+0x5b/0x1f1
 load_module+0x1db1/0x2690
 ? m_show+0x1d0/0x1d0
 __do_sys_finit_module+0xc5/0xd0
 __x64_sys_finit_module+0x15/0x20
 do_syscall_64+0x6b/0x1d0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

If pci_register_driver fails, register inet6addr_notifier is
pointless. This patch fix the error path in cxgb4_init_module.

Fixes: b5a02f50 ("cxgb4 : Update ipv6 address handling api")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -6161,15 +6161,24 @@ static int __init cxgb4_init_module(void)
 
 	ret = pci_register_driver(&cxgb4_driver);
 	if (ret < 0)
-		debugfs_remove(cxgb4_debugfs_root);
+		goto err_pci;
 
 #if IS_ENABLED(CONFIG_IPV6)
 	if (!inet6addr_registered) {
-		register_inet6addr_notifier(&cxgb4_inet6addr_notifier);
-		inet6addr_registered = true;
+		ret = register_inet6addr_notifier(&cxgb4_inet6addr_notifier);
+		if (ret)
+			pci_unregister_driver(&cxgb4_driver);
+		else
+			inet6addr_registered = true;
 	}
 #endif
 
+	if (ret == 0)
+		return ret;
+
+err_pci:
+	debugfs_remove(cxgb4_debugfs_root);
+
 	return ret;
 }