[02/13] scsi: iscsi: fix lun/target reset cmd cleanup handling

Message ID 20210413230648.5593-3-michael.christie@oracle.com
State New
Headers show
Series
  • scsi: libicsi and qedi tmf fixes
Related show

Commit Message

Mike Christie April 13, 2021, 11:06 p.m.
If we are handling a sg io reset there is a small window where cmds can
sneak into iscsi_queuecommand even though tmf_in_progress is set. This
seems to not be a problem for normal drivers because they know exactly
what was sent to the fw. For libiscsi this is a problem because it knows
what it sent to the driver but not what the driver sent to the fw.
When we go to cleanup then libiscsi might cleanup the sneaky cmd but
the driver/fw may not have seen the sneaky cmd and it's left running
in fw.

This has libiscsi just stop queueing cmds when it sends the tmf down
to the driver. Both then know they see the same set of cmds.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/scsi/libiscsi.c | 104 +++++++++++++++++++++++++++-------------
 1 file changed, 72 insertions(+), 32 deletions(-)

Patch

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 04633e5157e9..3ff440d37a36 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1669,29 +1669,11 @@  enum {
 	FAILURE_SESSION_NOT_READY,
 };
 
-int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
+static bool iscsi_eh_running(struct iscsi_conn *conn, struct scsi_cmnd *sc,
+			     int *reason)
 {
-	struct iscsi_cls_session *cls_session;
-	struct iscsi_host *ihost;
-	int reason = 0;
-	struct iscsi_session *session;
-	struct iscsi_conn *conn;
-	struct iscsi_task *task = NULL;
-
-	sc->result = 0;
-	sc->SCp.ptr = NULL;
-
-	ihost = shost_priv(host);
-
-	cls_session = starget_to_session(scsi_target(sc->device));
-	session = cls_session->dd_data;
-	spin_lock_bh(&session->frwd_lock);
-
-	reason = iscsi_session_chkready(cls_session);
-	if (reason) {
-		sc->result = reason;
-		goto fault;
-	}
+	struct iscsi_session *session = conn->session;
+	struct iscsi_tm *tmf;
 
 	if (session->state != ISCSI_STATE_LOGGED_IN) {
 		/*
@@ -1707,31 +1689,92 @@  int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
 			 * state is bad, allowing completion to happen
 			 */
 			if (unlikely(system_state != SYSTEM_RUNNING)) {
-				reason = FAILURE_SESSION_FAILED;
+				*reason = FAILURE_SESSION_FAILED;
 				sc->result = DID_NO_CONNECT << 16;
 				break;
 			}
 			fallthrough;
 		case ISCSI_STATE_IN_RECOVERY:
-			reason = FAILURE_SESSION_IN_RECOVERY;
+			*reason = FAILURE_SESSION_IN_RECOVERY;
 			sc->result = DID_IMM_RETRY << 16;
 			break;
 		case ISCSI_STATE_LOGGING_OUT:
-			reason = FAILURE_SESSION_LOGGING_OUT;
+			*reason = FAILURE_SESSION_LOGGING_OUT;
 			sc->result = DID_IMM_RETRY << 16;
 			break;
 		case ISCSI_STATE_RECOVERY_FAILED:
-			reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
+			*reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
 			sc->result = DID_TRANSPORT_FAILFAST << 16;
 			break;
 		case ISCSI_STATE_TERMINATE:
-			reason = FAILURE_SESSION_TERMINATE;
+			*reason = FAILURE_SESSION_TERMINATE;
 			sc->result = DID_NO_CONNECT << 16;
 			break;
 		default:
-			reason = FAILURE_SESSION_FREED;
+			*reason = FAILURE_SESSION_FREED;
 			sc->result = DID_NO_CONNECT << 16;
 		}
+		goto eh_running;
+	}
+
+	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
+		*reason = FAILURE_SESSION_IN_RECOVERY;
+		sc->result = DID_REQUEUE << 16;
+		goto eh_running;
+	}
+
+	/*
+	 * For sg resets make sure libiscsi, the drivers and their fw see the
+	 * same cmds. Once we get a TMF that can affect multiple drivers stop
+	 * queueing.
+	 */
+	if (conn->tmf_state != TMF_INITIAL) {
+		tmf = &conn->tmhdr;
+
+		switch (ISCSI_TM_FUNC_VALUE(tmf)) {
+		case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
+			if (sc->device->lun != scsilun_to_int(&tmf->lun))
+				return 0;
+
+			ISCSI_DBG_EH(conn->session,
+				     "Requeue cmd sent during LU RESET processing.\n");
+			sc->result = DID_REQUEUE << 16;
+			goto eh_running;
+		case ISCSI_TM_FUNC_TARGET_WARM_RESET:
+			ISCSI_DBG_EH(conn->session,
+				     "Requeue cmd sent during TARGET RESET processing.\n");
+			sc->result = DID_REQUEUE << 16;
+			goto eh_running;
+		}
+	}
+
+	return false;
+
+eh_running:
+	return true;
+}
+
+int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
+{
+	struct iscsi_cls_session *cls_session;
+	struct iscsi_host *ihost;
+	int reason = 0;
+	struct iscsi_session *session;
+	struct iscsi_conn *conn;
+	struct iscsi_task *task = NULL;
+
+	sc->result = 0;
+	sc->SCp.ptr = NULL;
+
+	ihost = shost_priv(host);
+
+	cls_session = starget_to_session(scsi_target(sc->device));
+	session = cls_session->dd_data;
+	spin_lock_bh(&session->frwd_lock);
+
+	reason = iscsi_session_chkready(cls_session);
+	if (reason) {
+		sc->result = reason;
 		goto fault;
 	}
 
@@ -1742,11 +1785,8 @@  int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
 		goto fault;
 	}
 
-	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
-		reason = FAILURE_SESSION_IN_RECOVERY;
-		sc->result = DID_REQUEUE << 16;
+	if (iscsi_eh_running(conn, sc, &reason))
 		goto fault;
-	}
 
 	if (iscsi_check_cmdsn_window_closed(conn)) {
 		reason = FAILURE_WINDOW_CLOSED;