[PATCH 22/36] scsi: libiscsi: Prepare for enabling lock context analysis

[Bart Van Assche <bvanassche@acm.org>]

Document locking requirements with __must_hold().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/libiscsi.c | 19 ++++++++++++++++++-
 include/scsi/libiscsi.h |  5 +++--
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 25857d6ed6e8..b89c048b4034 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1088,6 +1088,7 @@ static int iscsi_nop_out_rsp(struct iscsi_task *task,
 
 static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 			       char *data, int datalen)
+	__must_hold(&conn->session->back_lock)
 {
 	struct iscsi_reject *reject = (struct iscsi_reject *)hdr;
 	struct iscsi_hdr rejected_pdu;
@@ -1500,6 +1501,7 @@ static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn)
 
 static int iscsi_xmit_task(struct iscsi_conn *conn, struct iscsi_task *task,
 			   bool was_requeue)
+	__must_hold(&conn->session->frwd_lock)
 {
 	int rc;
 
@@ -1915,7 +1917,8 @@ static void iscsi_tmf_timedout(struct timer_list *t)
 static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
 				   struct iscsi_tm *hdr, int age,
 				   int timeout)
-	__must_hold(&session->frwd_lock)
+	__must_hold(&conn->session->frwd_lock)
+	__must_hold(&conn->session->eh_mutex)
 {
 	struct iscsi_session *session = conn->session;
 
@@ -1962,6 +1965,7 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
  * Fail commands. session frwd lock held and xmit thread flushed.
  */
 static void fail_scsi_tasks(struct iscsi_conn *conn, u64 lun, int error)
+	__must_hold(&conn->session->frwd_lock)
 {
 	struct iscsi_session *session = conn->session;
 	struct iscsi_task *task;
@@ -2408,6 +2412,9 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
 
 	ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n", sc, task->itt);
 	conn = session->leadconn;
+	/* Tell the compiler that conn->session == session. */
+	__assume_ctx_lock(&conn->session->eh_mutex);
+	__assume_ctx_lock(&conn->session->frwd_lock);
 	iscsi_get_conn(conn->cls_conn);
 	conn->eh_abort_cnt++;
 	age = session->age;
@@ -2531,6 +2538,9 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
 	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN)
 		goto unlock;
 	conn = session->leadconn;
+	/* Tell the compiler that conn->session == session. */
+	__assume_ctx_lock(&conn->session->frwd_lock);
+	__assume_ctx_lock(&conn->session->eh_mutex);
 
 	/* only have one tmf outstanding at a time */
 	if (session->tmf_state != TMF_INITIAL)
@@ -2564,6 +2574,8 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
 	iscsi_suspend_tx(conn);
 
 	spin_lock_bh(&session->frwd_lock);
+	/* Tell the compiler that conn->session == session. */
+	__assume_ctx_lock(&conn->session->frwd_lock);
 	memset(hdr, 0, sizeof(*hdr));
 	fail_scsi_tasks(conn, sc->device->lun, DID_ERROR);
 	session->tmf_state = TMF_INITIAL;
@@ -2693,6 +2705,9 @@ static int iscsi_eh_target_reset(struct scsi_cmnd *sc)
 	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN)
 		goto unlock;
 	conn = session->leadconn;
+	/* Tell the compiler that conn->session == session. */
+	__assume_ctx_lock(&conn->session->eh_mutex);
+	__assume_ctx_lock(&conn->session->frwd_lock);
 
 	/* only have one tmf outstanding at a time */
 	if (session->tmf_state != TMF_INITIAL)
@@ -2726,6 +2741,8 @@ static int iscsi_eh_target_reset(struct scsi_cmnd *sc)
 	iscsi_suspend_tx(conn);
 
 	spin_lock_bh(&session->frwd_lock);
+	/* Tell the compiler that conn->session == session. */
+	__assume_ctx_lock(&conn->session->frwd_lock);
 	memset(hdr, 0, sizeof(*hdr));
 	fail_scsi_tasks(conn, -1, DID_ERROR);
 	session->tmf_state = TMF_INITIAL;
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 3d765c77bcd9..d39b5b268e6f 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -474,8 +474,9 @@ extern int iscsi_conn_send_pdu(struct iscsi_cls_conn *, struct iscsi_hdr *,
 				char *, uint32_t);
 extern int iscsi_complete_pdu(struct iscsi_conn *, struct iscsi_hdr *,
 			      char *, int);
-extern int __iscsi_complete_pdu(struct iscsi_conn *, struct iscsi_hdr *,
-				char *, int);
+extern int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *,
+				char *, int)
+		__must_hold(&conn->session->back_lock);
 extern int iscsi_verify_itt(struct iscsi_conn *, itt_t);
 extern struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *, itt_t);
 extern struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *, itt_t);