scsi: lpfc: Fix crash in blk_mq layer when executing modprobe -r lpfc

modprobe -r lpfc produces the following:

Call Trace:
 __blk_mq_run_hw_queue+0xa2/0xb0
 __blk_mq_delay_run_hw_queue+0x9d/0xb0
 ? blk_mq_hctx_has_pending+0x32/0x80
 blk_mq_run_hw_queue+0x50/0xd0
 blk_mq_sched_insert_request+0x110/0x1b0
 blk_execute_rq_nowait+0x76/0x180
 nvme_keep_alive_work+0x8a/0xd0 [nvme_core]
 process_one_work+0x17f/0x440
 worker_thread+0x126/0x3c0
 ? manage_workers.isra.24+0x2a0/0x2a0
 kthread+0xd1/0xe0
 ? insert_kthread_work+0x40/0x40
 ret_from_fork_nospec_begin+0x21/0x21
 ? insert_kthread_work+0x40/0x40

However, rmmod lpfc would run correctly.

When an nvme remoteport is unregistered with the host nvme transport, it
needs to set the remoteport->dev_loss_tmo value 0 to indicate an immediate
termination of device loss and prevent any further keep alives to that
rport.  The driver was never setting dev_loss_tmo causing the nvme
transport to continue to send the keep alive.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_nvme.c

@@ -2862,6 +2862,15 @@ lpfc_nvme_unregister_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 		 * The transport will update it.
 		 */
 		ndlp->upcall_flags |= NLP_WAIT_FOR_UNREG;
+
+		/* Don't let the host nvme transport keep sending keep-alives
+		 * on this remoteport. Vport is unloading, no recovery. The
+		 * return values is ignored.  The upcall is a courtesy to the
+		 * transport.
+		 */
+		if (vport->load_flag & FC_UNLOADING)
+			(void)nvme_fc_set_remoteport_devloss(remoteport, 0);
+
 		ret = nvme_fc_unregister_remoteport(remoteport);
 		if (ret != 0) {
 			lpfc_nlp_put(ndlp);