linux-kernel - [PATCH 4.18 32/53] scsi: lpfc: Synchronize access to remoteport via rport

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Date:   Thu, 18 Oct 2018 19:54:25 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dick Kennedy <dick.kennedy@...adcom.com>,
        James Smart <jsmart2021@...il.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.18 32/53] scsi: lpfc: Synchronize access to remoteport via rport

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Smart <jsmart2021@...il.com>

[ Upstream commit 9e210178267b80c4eeb832fade7e146a18c84915 ]

The driver currently uses the ndlp to get the local rport which is then used
to get the nvme transport remoteport pointer. There can be cases where a stale
remoteport pointer is obtained as synchronization isn't done through the
different dereferences.

Correct by using locks to synchronize the dereferences.

Signed-off-by: Dick Kennedy <dick.kennedy@...adcom.com>
Signed-off-by: James Smart <jsmart2021@...il.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/scsi/lpfc/lpfc_attr.c    |   15 ++++++++++-----
 drivers/scsi/lpfc/lpfc_debugfs.c |   10 +++++-----
 drivers/scsi/lpfc/lpfc_nvme.c    |   11 ++++++++---
 3 files changed, 23 insertions(+), 13 deletions(-)

--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -320,12 +320,12 @@ lpfc_nvme_info_show(struct device *dev,
 			localport->port_id, statep);
 
 	list_for_each_entry(ndlp, &vport->fc_nodes, nlp_listp) {
+		nrport = NULL;
+		spin_lock(&vport->phba->hbalock);
 		rport = lpfc_ndlp_get_nrport(ndlp);
-		if (!rport)
-			continue;
-
-		/* local short-hand pointer. */
-		nrport = rport->remoteport;
+		if (rport)
+			nrport = rport->remoteport;
+		spin_unlock(&vport->phba->hbalock);
 		if (!nrport)
 			continue;
 
@@ -3304,6 +3304,7 @@ lpfc_update_rport_devloss_tmo(struct lpf
 	struct lpfc_nodelist  *ndlp;
 #if (IS_ENABLED(CONFIG_NVME_FC))
 	struct lpfc_nvme_rport *rport;
+	struct nvme_fc_remote_port *remoteport = NULL;
 #endif
 
 	shost = lpfc_shost_from_vport(vport);
@@ -3314,8 +3315,12 @@ lpfc_update_rport_devloss_tmo(struct lpf
 		if (ndlp->rport)
 			ndlp->rport->dev_loss_tmo = vport->cfg_devloss_tmo;
 #if (IS_ENABLED(CONFIG_NVME_FC))
+		spin_lock(&vport->phba->hbalock);
 		rport = lpfc_ndlp_get_nrport(ndlp);
 		if (rport)
+			remoteport = rport->remoteport;
+		spin_unlock(&vport->phba->hbalock);
+		if (remoteport)
 			nvme_fc_set_remoteport_devloss(rport->remoteport,
 						       vport->cfg_devloss_tmo);
 #endif
--- a/drivers/scsi/lpfc/lpfc_debugfs.c
+++ b/drivers/scsi/lpfc/lpfc_debugfs.c
@@ -551,7 +551,7 @@ lpfc_debugfs_nodelist_data(struct lpfc_v
 	unsigned char *statep;
 	struct nvme_fc_local_port *localport;
 	struct lpfc_nvmet_tgtport *tgtp;
-	struct nvme_fc_remote_port *nrport;
+	struct nvme_fc_remote_port *nrport = NULL;
 	struct lpfc_nvme_rport *rport;
 
 	cnt = (LPFC_NODELIST_SIZE / LPFC_NODELIST_ENTRY_SIZE);
@@ -696,11 +696,11 @@ lpfc_debugfs_nodelist_data(struct lpfc_v
 	len += snprintf(buf + len, size - len, "\tRport List:\n");
 	list_for_each_entry(ndlp, &vport->fc_nodes, nlp_listp) {
 		/* local short-hand pointer. */
+		spin_lock(&phba->hbalock);
 		rport = lpfc_ndlp_get_nrport(ndlp);
-		if (!rport)
-			continue;
-
-		nrport = rport->remoteport;
+		if (rport)
+			nrport = rport->remoteport;
+		spin_unlock(&phba->hbalock);
 		if (!nrport)
 			continue;
 
--- a/drivers/scsi/lpfc/lpfc_nvme.c
+++ b/drivers/scsi/lpfc/lpfc_nvme.c
@@ -2718,7 +2718,9 @@ lpfc_nvme_register_port(struct lpfc_vpor
 	rpinfo.port_name = wwn_to_u64(ndlp->nlp_portname.u.wwn);
 	rpinfo.node_name = wwn_to_u64(ndlp->nlp_nodename.u.wwn);
 
+	spin_lock_irq(&vport->phba->hbalock);
 	oldrport = lpfc_ndlp_get_nrport(ndlp);
+	spin_unlock_irq(&vport->phba->hbalock);
 	if (!oldrport)
 		lpfc_nlp_get(ndlp);
 
@@ -2833,7 +2835,7 @@ lpfc_nvme_unregister_port(struct lpfc_vp
 	struct nvme_fc_local_port *localport;
 	struct lpfc_nvme_lport *lport;
 	struct lpfc_nvme_rport *rport;
-	struct nvme_fc_remote_port *remoteport;
+	struct nvme_fc_remote_port *remoteport = NULL;
 
 	localport = vport->localport;
 
@@ -2847,11 +2849,14 @@ lpfc_nvme_unregister_port(struct lpfc_vp
 	if (!lport)
 		goto input_err;
 
+	spin_lock_irq(&vport->phba->hbalock);
 	rport = lpfc_ndlp_get_nrport(ndlp);
-	if (!rport)
+	if (rport)
+		remoteport = rport->remoteport;
+	spin_unlock_irq(&vport->phba->hbalock);
+	if (!remoteport)
 		goto input_err;
 
-	remoteport = rport->remoteport;
 	lpfc_printf_vlog(vport, KERN_INFO, LOG_NVME_DISC,
 			 "6033 Unreg nvme remoteport %p, portname x%llx, "
 			 "port_id x%06x, portstate x%x port type x%x\n",