Commit ed830385 ("scsi: ibmvfc: Avoid loss of all paths during SVC node
reboot") introduced a regression where when the client resets or re-enables
its CRQ with the hypervisor there is a chance that if the server side
doesn't issue its INIT handshake quick enough the client can issue an
Implicit Logout prior to doing an NPIV Login. The server treats this
scenario as a protocol violation and closes the CRQ on its end forcing the
client through a reset that gets the client host state and next host action
out of agreement leading to a BUG assert.

ibmvfc 30000003: Partner initialization complete
ibmvfc 30000002: Partner initialization complete
ibmvfc 30000002: Host partner adapter deregistered or failed (rc=2)
ibmvfc 30000002: Partner initialized
------------[ cut here ]------------
kernel BUG at ../drivers/scsi/ibmvscsi/ibmvfc.c:4489!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Supported: No, Unreleased kernel
CPU: 16 PID: 1290 Comm: ibmvfc_0 Tainted: G           OE  X   5.3.18-12-default
NIP:  c00800000d84a2b4 LR: c00800000d84a040 CTR: c00800000d84a2a0
REGS: c00000000cb57a00 TRAP: 0700   Tainted: G           OE  X    (5.3.18-12-default)
MSR:  800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 24000848  XER: 00000001
CFAR: c00800000d84a070 IRQMASK: 1
GPR00: c00800000d84a040 c00000000cb57c90 c00800000d858e00 0000000000000000
GPR04: 0000000000000000 0000000000000000 0000000000000000 00000000000000a0
GPR08: c00800000d84a074 0000000000000001 0000000000000014 c00800000d84d7d0
GPR12: 0000000000000000 c00000001ea28200 c00000000016cd98 0000000000000000
GPR16: c00800000d84b7b8 0000000000000000 0000000000000000 c00000542c706d68
GPR20: 0000000000000005 c00000542c706d88 5deadbeef0000100 5deadbeef0000122
GPR24: 000000000000000c 000000000000000b c00800000d852180 0000000000000001
GPR28: 0000000000000000 c00000542c706da0 c00000542c706860 c00000542c706828
NIP [c00800000d84a2b4] ibmvfc_work+0x3ac/0xc90 [ibmvfc]
LR [c00800000d84a040] ibmvfc_work+0x138/0xc90 [ibmvfc]

This scenario can be prevented by rejecting any attempt to send an Implicit
Logout if the client adapter is not logged in yet.

Link: https://lore.kernel.org/r/20200427214824.6890-1-tyreld@linux.ibm.com
Fixes: ed830385 ("scsi: ibmvfc: Avoid loss of all paths during SVC node reboot")
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>