On tests adding and removing a remote port, calls to nvme_info would
eventually show fewer target ports discovered than were present in
the san. Additionally, the following error messages were seen:
  6031 RemotePort Registration failed err: -116, DID x471301

There is a race condition that exists between the driver and the nvme
transport on remote port unregister vs the confirmed deletion. It's
possible that the driver may rediscover the remote port and reregister
the remote port before a prior unregister delete callback was made
(as it rebinded to the prior remoteport structure). However, the
driver was coded to expect the callback before seeing the remote
port again thus a new registration. The logic results in the driver
having an invalid remoteport pointer set.

Correct by tracking when waiting for the delete callback. In cases
where the ndlp remoteport pointer is updated, it is only cleared
when the wait has not been superceded by a prior registration.

Signed-off-by: Dick Kennedy <dick.kenn...@broadcom.com>
Signed-off-by: James Smart <james.sm...@broadcom.com>
Reviewed-by: Hannes Reinecke <h...@suse.com>
 drivers/scsi/lpfc/lpfc_nvme.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_nvme.c b/drivers/scsi/lpfc/lpfc_nvme.c
index 22962b08c275..a0257478b63c 100644
--- a/drivers/scsi/lpfc/lpfc_nvme.c
+++ b/drivers/scsi/lpfc/lpfc_nvme.c
@@ -334,8 +334,14 @@ lpfc_nvme_remoteport_delete(struct nvme_fc_remote_port 
                        "6146 remoteport delete of remoteport %p\n",
-       ndlp->nrport = NULL;
-       ndlp->upcall_flags &= ~NLP_WAIT_FOR_UNREG;
+       /* The register rebind might have occurred before the delete
+        * downcall.  Guard against this race.
+        */
+       if (ndlp->upcall_flags & NLP_WAIT_FOR_UNREG) {
+               ndlp->nrport = NULL;
+               ndlp->upcall_flags &= ~NLP_WAIT_FOR_UNREG;
+       }
        /* Remove original register reference. The host transport
@@ -2691,6 +2697,12 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct 
lpfc_nodelist *ndlp)
                 * a resume of the existing rport.  Else this is a
                 * new rport.
+               /* Guard against an unregister/reregister
+                * race that leaves the WAIT flag set.
+                */
+               spin_lock_irq(&vport->phba->hbalock);
+               ndlp->upcall_flags &= ~NLP_WAIT_FOR_UNREG;
+               spin_unlock_irq(&vport->phba->hbalock);
                rport = remote_port->private;
                if (oldrport) {
                        if (oldrport == remote_port->private) {

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