scsi: lpfc: Fix refcounting around SCSI and NVMe transport APIs

Due to bug history and code review, the node reference counting approach in
the driver isn't implemented consistently with how the scsi and nvme
transport perform registrations and unregistrations and their callbacks.
This resulted in many bad/stale node pointers.

Reword the driver so that reference handling is performed as follows:

 - The initial node reference is taken on structure allocation

 - Take a reference on any add/register call to the transport

 - Remove a reference on any delete/unregister call to the transport

 - After the node has fully removed from both the SCSI and NVMEe transports
   (dev_loss_callbacks have called back) call the discovery engine
   DEVICE_RM event which will remove the final reference and release the
   node structure.

 - Alter dev_loss handling when a vport or base port is unloading.

 - Remove the put_node handling - no longer needed.

 - Rewrite the vport_delete handling on reference counts.  Part of this
   effort was driven from the FDISC not registering with the transport and
   disrupting the model for node reference counting.

 - Deleted lpfc_nlp_remove.  Pushed it's remaining ops into
   lpfc_nlp_release.

 - Several other small code cleanups.

Link: https://lore.kernel.org/r/20201115192646.12977-5-james.smart@broadcom.com
Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/scsi/lpfc/lpfc_disc.h b/drivers/scsi/lpfc/lpfc_disc.h
index 09d4ec2a20db..b831f10a686c 100644
--- a/drivers/scsi/lpfc/lpfc_disc.h
+++ b/drivers/scsi/lpfc/lpfc_disc.h
@@ -131,13 +131,17 @@ struct lpfc_nodelist {
 	unsigned long *active_rrqs_xri_bitmap;
 	struct lpfc_scsicmd_bkt *lat_data;	/* Latency data */
 	uint32_t fc4_prli_sent;
-	uint32_t upcall_flags;
+	uint32_t fc4_xpt_flags;
 #define NLP_WAIT_FOR_UNREG    0x1
+#define SCSI_XPT_REGD         0x2
+#define NVME_XPT_REGD         0x4
+
 
 	uint32_t nvme_fb_size; /* NVME target's supported byte cnt */
 #define NVME_FB_BIT_SHIFT 9    /* PRLI Rsp first burst in 512B units. */
 	uint32_t nlp_defer_did;
 };
+
 struct lpfc_node_rrq {
 	struct list_head list;
 	uint16_t xritag;