scsi: qedf: fc_rport_priv reference counting fixes

The fc_rport_priv structure is reference counted, so we need to ensure that
the reference is increased before accessing the structure.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 30 insertions, 9 deletions

diff --git a/drivers/scsi/qedf/qedf_els.c b/drivers/scsi/qedf/qedf_els.c
index f1f576375de4..1781e732d24a 100644
--- a/drivers/scsi/qedf/qedf_els.c
+++ b/drivers/scsi/qedf/qedf_els.c
@@ -378,12 +378,18 @@ void qedf_restart_rport(struct qedf_rport *fcport)
 	spin_unlock_irqrestore(&fcport->rport_lock, flags);
 
 	rdata = fcport->rdata;
-	if (rdata) {
+	if (rdata && !kref_get_unless_zero(&rdata->kref)) {
+		fcport->rdata = NULL;
+		rdata = NULL;
+	}
+
+	if (rdata && rdata->rp_state == RPORT_ST_READY) {
 		lport = fcport->qedf->lport;
 		port_id = rdata->ids.port_id;
 		QEDF_ERR(&(fcport->qedf->dbg_ctx),
 		    "LOGO port_id=%x.\n", port_id);
 		fc_rport_logoff(rdata);
+		kref_put(&rdata->kref, fc_rport_destroy);
 		mutex_lock(&lport->disc.disc_mutex);
 		/* Recreate the rport and log back in */
 		rdata = fc_rport_create(lport, port_id);
@@ -393,6 +399,7 @@ void qedf_restart_rport(struct qedf_rport *fcport)
 			fcport->rdata = rdata;
 		} else {
 			mutex_unlock(&lport->disc.disc_mutex);
+			fcport->rdata = NULL;
 		}
 	}
 	clear_bit(QEDF_RPORT_IN_RESET, &fcport->flags);
diff --git a/drivers/scsi/qedf/qedf_io.c b/drivers/scsi/qedf/qedf_io.c
index 57c3aa4fb708..56d211674a9a 100644
--- a/drivers/scsi/qedf/qedf_io.c
+++ b/drivers/scsi/qedf/qedf_io.c
@@ -1799,6 +1799,7 @@ int qedf_initiate_abts(struct qedf_ioreq *io_req, bool return_scsi_cmd_on_abts)
 		goto out;
 	}
 
+	qedf = fcport->qedf;
 	rdata = fcport->rdata;
 
 	if (!rdata || !kref_get_unless_zero(&rdata->kref)) {
@@ -1808,32 +1809,31 @@ int qedf_initiate_abts(struct qedf_ioreq *io_req, bool return_scsi_cmd_on_abts)
 	}
 
 	r_a_tov = rdata->r_a_tov;
-	qedf = fcport->qedf;
 	lport = qedf->lport;
 
 	if (lport->state != LPORT_ST_READY || !(lport->link_up)) {
 		QEDF_ERR(&(qedf->dbg_ctx), "link is not ready\n");
 		rc = 1;
-		goto out;
+		goto drop_rdata_kref;
 	}
 
 	if (atomic_read(&qedf->link_down_tmo_valid) > 0) {
 		QEDF_ERR(&(qedf->dbg_ctx), "link_down_tmo active.\n");
 		rc = 1;
-		goto out;
+		goto drop_rdata_kref;
 	}
 
 	/* Ensure room on SQ */
 	if (!atomic_read(&fcport->free_sqes)) {
 		QEDF_ERR(&(qedf->dbg_ctx), "No SQ entries available\n");
 		rc = 1;
-		goto out;
+		goto drop_rdata_kref;
 	}
 
 	if (test_bit(QEDF_RPORT_UPLOADING_CONNECTION, &fcport->flags)) {
 		QEDF_ERR(&qedf->dbg_ctx, "fcport is uploading.\n");
 		rc = 1;
-		goto out;
+		goto drop_rdata_kref;
 	}
 
 	if (!test_bit(QEDF_CMD_OUTSTANDING, &io_req->flags) ||
@@ -1843,7 +1843,7 @@ int qedf_initiate_abts(struct qedf_ioreq *io_req, bool return_scsi_cmd_on_abts)
 			  "cleanup or abort processing or already "
 			  "completed.\n", io_req->xid);
 		rc = 1;
-		goto out;
+		goto drop_rdata_kref;
 	}
 
 	kref_get(&io_req->refcount);
@@ -1876,6 +1876,8 @@ int qedf_initiate_abts(struct qedf_ioreq *io_req, bool return_scsi_cmd_on_abts)
 
 	spin_unlock_irqrestore(&fcport->rport_lock, flags);
 
+drop_rdata_kref:
+	kref_put(&rdata->kref, fc_rport_destroy);
 out:
 	return rc;
 }
@@ -2217,6 +2219,7 @@ static int qedf_execute_tmf(struct qedf_rport *fcport, struct scsi_cmnd *sc_cmd,
 	unsigned long flags;
 	struct fcoe_wqe *sqe;
 	u16 sqe_idx;
+	struct fc_rport_priv *rdata = fcport->rdata;
 
 	if (!sc_cmd) {
 		QEDF_ERR(&(qedf->dbg_ctx), "invalid arg\n");
@@ -2230,8 +2233,13 @@ static int qedf_execute_tmf(struct qedf_rport *fcport, struct scsi_cmnd *sc_cmd,
 		return FAILED;
 	}
 
-	QEDF_INFO(&(qedf->dbg_ctx), QEDF_LOG_SCSI_TM, "portid = 0x%x "
-		   "tm_flags = %d\n", fcport->rdata->ids.port_id, tm_flags);
+	if (!rdata || !kref_get_unless_zero(&rdata->kref)) {
+		QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_SCSI_TM, "stale rport\n");
+		return FAILED;
+	}
+	QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_SCSI_TM,
+		  "portid = 0x%x tm_flags = %d\n",
+		  rdata->ids.port_id, tm_flags);
 
 	io_req = qedf_alloc_cmd(fcport, QEDF_TASK_MGMT_CMD);
 	if (!io_req) {
@@ -2327,6 +2335,7 @@ no_flush:
 		rc = SUCCESS;
 	}
 reset_tmf_err:
+	kref_put(&rdata->kref, fc_rport_destroy);
 	return rc;
 }
 
diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
index ad72a1eb3bca..84834d4490ff 100644
--- a/drivers/scsi/qedf/qedf_main.c
+++ b/drivers/scsi/qedf/qedf_main.c
@@ -1334,6 +1334,8 @@ static void qedf_upload_connection(struct qedf_ctx *qedf,
 static void qedf_cleanup_fcport(struct qedf_ctx *qedf,
 	struct qedf_rport *fcport)
 {
+	struct fc_rport_priv *rdata = fcport->rdata;
+
 	QEDF_INFO(&(qedf->dbg_ctx), QEDF_LOG_CONN, "Cleaning up portid=%06x.\n",
 	    fcport->rdata->ids.port_id);
 
@@ -1345,6 +1347,7 @@ static void qedf_cleanup_fcport(struct qedf_ctx *qedf,
 	qedf_free_sq(qedf, fcport);
 	fcport->rdata = NULL;
 	fcport->qedf = NULL;
+	kref_put(&rdata->kref, fc_rport_destroy);
 }
 
 /**
@@ -1420,6 +1423,8 @@ static void qedf_rport_event_handler(struct fc_lport *lport,
 			break;
 		}
 
+		/* Initial reference held on entry, so this can't fail */
+		kref_get(&rdata->kref);
 		fcport->rdata = rdata;
 		fcport->rport = rport;