[PATCH v3 01/20] lpfc: Fix plogi collision that causes illegal state transition

[James Smart <jsmart2021@gmail.com>]

From: Dick Kennedy <dick.kennedy@broadcom.com>

Message "0271 Illegal State Transition: node" seen in logs, all
luns are unuseable for that target.

A window exists in the rcv_plogi path where if the state is plogi
issue but the driver has not issued a plogi, then two reglogins will
be sent for the same RPI. The first one to complete will advance
the state to prli issue the second one will be detected as an
illegal state, and leave the node in an unusable state.

Correct the completion routine for the PLOGI ACC that detects the
state change when the driver starts discovery on the node again
and drop the REGLOGIN mailbox command.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

---
v3:
  revise if test for better indentation per review
  removed unnecessary typecast
---
 drivers/scsi/lpfc/lpfc_els.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 6d1d6f691df4..2dae501dc323 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -3930,7 +3930,25 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 	if (mbox) {
 		if ((rspiocb->iocb.ulpStatus == 0)
 		    && (ndlp->nlp_flag & NLP_ACC_REGLOGIN)) {
-			lpfc_unreg_rpi(vport, ndlp);
+			if (!lpfc_unreg_rpi(vport, ndlp) &&
+			    (ndlp->nlp_state ==  NLP_STE_PLOGI_ISSUE ||
+			     ndlp->nlp_state == NLP_STE_REG_LOGIN_ISSUE)) {
+				lpfc_printf_vlog(vport, KERN_INFO,
+					LOG_DISCOVERY,
+					"0314 PLOGI recov DID x%x "
+					"Data: x%x x%x x%x\n",
+					ndlp->nlp_DID, ndlp->nlp_state,
+					ndlp->nlp_rpi, ndlp->nlp_flag);
+				mp = mbox->context1;
+				if (mp) {
+					lpfc_mbuf_free(phba, mp->virt,
+						       mp->phys);
+					kfree(mp);
+				}
+				mempool_free(mbox, phba->mbox_mem_pool);
+				goto out;
+			}
+
 			/* Increment reference count to ndlp to hold the
 			 * reference to ndlp for the callback function.
 			 */
-- 
2.13.1