nvme_fc: add aen abort to teardown

Add abort support for aens. Commonized the op abort to apply to aen or
real ios (caused some reorg/routine movement). Abort path sets termination
flag in prep for next patch that will be watching i/o abort completion
before proceeding with controller teardown.

Now that we're aborting aens, the "exit" code that simply cleared out
their context no longer applies.

Also clarified how we detect an AEN vs a normal io - by a flag, not
by whether a rq exists or the a rqno is out of range.

Note: saw some interesting cases where if the queues are stopped and
we're waiting for the aborts, the core layer can call the complete_rq
callback for the io. So the io completion synchronizes link side completion
with possible blk layer completion under error.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/fc.c

@@ -65,6 +65,7 @@ enum nvme_fcop_flags {
 	FCOP_FLAGS_TERMIO	= (1 << 0),
 	FCOP_FLAGS_RELEASED	= (1 << 1),
 	FCOP_FLAGS_COMPLETE	= (1 << 2),
+	FCOP_FLAGS_AEN		= (1 << 3),
 };
 
 struct nvmefc_ls_req_op {
@@ -86,6 +87,7 @@ enum nvme_fcpop_state {
 	FCPOP_STATE_IDLE	= 1,
 	FCPOP_STATE_ACTIVE	= 2,
 	FCPOP_STATE_ABORTED	= 3,
+	FCPOP_STATE_COMPLETE	= 4,
 };
 
 struct nvme_fc_fcp_op {
@@ -104,6 +106,7 @@ struct nvme_fc_fcp_op {
 	struct request		*rq;
 
 	atomic_t		state;
+	u32			flags;
 	u32			rqno;
 	u32			nents;
 
@@ -1132,6 +1135,7 @@ nvme_fc_xmt_disconnect_assoc(struct nvme_fc_ctrl *ctrl)
 
 /* *********************** NVME Ctrl Routines **************************** */
 
+static void __nvme_fc_final_op_cleanup(struct request *rq);
 
 static int
 nvme_fc_reinit_request(void *data, struct request *rq)
@@ -1169,20 +1173,74 @@ nvme_fc_exit_request(void *data, struct request *rq,
 	return __nvme_fc_exit_request(data, op);
 }
 
+static int
+__nvme_fc_abort_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_fcp_op *op)
+{
+	int state;
+
+	state = atomic_xchg(&op->state, FCPOP_STATE_ABORTED);
+	if (state != FCPOP_STATE_ACTIVE) {
+		atomic_set(&op->state, state);
+		return -ECANCELED;
+	}
+
+	ctrl->lport->ops->fcp_abort(&ctrl->lport->localport,
+					&ctrl->rport->remoteport,
+					op->queue->lldd_handle,
+					&op->fcp_req);
+
+	return 0;
+}
+
 static void
-nvme_fc_exit_aen_ops(struct nvme_fc_ctrl *ctrl)
+nvme_fc_abort_aen_ops(struct nvme_fc_ctrl *ctrl)
 {
 	struct nvme_fc_fcp_op *aen_op = ctrl->aen_ops;
-	int i;
+	unsigned long flags;
+	int i, ret;
 
 	for (i = 0; i < NVME_FC_NR_AEN_COMMANDS; i++, aen_op++) {
-		if (atomic_read(&aen_op->state) == FCPOP_STATE_UNINIT)
+		if (atomic_read(&aen_op->state) != FCPOP_STATE_ACTIVE)
 			continue;
-		__nvme_fc_exit_request(ctrl, aen_op);
-		nvme_fc_ctrl_put(ctrl);
+
+		spin_lock_irqsave(&ctrl->lock, flags);
+		aen_op->flags |= FCOP_FLAGS_TERMIO;
+		spin_unlock_irqrestore(&ctrl->lock, flags);
+
+		ret = __nvme_fc_abort_op(ctrl, aen_op);
+		if (ret) {
+			/*
+			 * if __nvme_fc_abort_op failed the io wasn't
+			 * active. Thus this call path is running in
+			 * parallel to the io complete. Treat as non-error.
+			 */
+
+			/* back out the flags/counters */
+			spin_lock_irqsave(&ctrl->lock, flags);
+			aen_op->flags &= ~FCOP_FLAGS_TERMIO;
+			spin_unlock_irqrestore(&ctrl->lock, flags);
+			return;
+		}
 	}
 }
 
+static inline int
+__nvme_fc_fcpop_chk_teardowns(struct nvme_fc_ctrl *ctrl,
+		struct nvme_fc_fcp_op *op)
+{
+	unsigned long flags;
+	bool complete_rq = false;
+
+	spin_lock_irqsave(&ctrl->lock, flags);
+	if (op->flags & FCOP_FLAGS_RELEASED)
+		complete_rq = true;
+	else
+		op->flags |= FCOP_FLAGS_COMPLETE;
+	spin_unlock_irqrestore(&ctrl->lock, flags);
+
+	return complete_rq;
+}
+
 void
 nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
 {
@@ -1195,6 +1253,7 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
 	struct nvme_command *sqe = &op->cmd_iu.sqe;
 	__le16 status = cpu_to_le16(NVME_SC_SUCCESS << 1);
 	union nvme_result result;
+	bool complete_rq;
 
 	/*
 	 * WARNING:
@@ -1289,13 +1348,25 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
 	}
 
 done:
-	if (!queue->qnum && op->rqno >= AEN_CMDID_BASE) {
+	if (op->flags & FCOP_FLAGS_AEN) {
 		nvme_complete_async_event(&queue->ctrl->ctrl, status, &result);
+		complete_rq = __nvme_fc_fcpop_chk_teardowns(ctrl, op);
+		atomic_set(&op->state, FCPOP_STATE_IDLE);
+		op->flags = FCOP_FLAGS_AEN;	/* clear other flags */
 		nvme_fc_ctrl_put(ctrl);
 		return;
 	}
 
-	nvme_end_request(rq, status, result);
+	complete_rq = __nvme_fc_fcpop_chk_teardowns(ctrl, op);
+	if (!complete_rq) {
+		if (unlikely(op->flags & FCOP_FLAGS_TERMIO)) {
+			status = cpu_to_le16(NVME_SC_ABORT_REQ);
+			if (blk_queue_dying(rq->q))
+				status |= cpu_to_le16(NVME_SC_DNR);
+		}
+		nvme_end_request(rq, status, result);
+	} else
+		__nvme_fc_final_op_cleanup(rq);
 }
 
 static int
@@ -1388,8 +1459,11 @@ nvme_fc_init_aen_ops(struct nvme_fc_ctrl *ctrl)
 		if (ret)
 			return ret;
 
+		aen_op->flags = FCOP_FLAGS_AEN;
+
 		memset(sqe, 0, sizeof(*sqe));
 		sqe->common.opcode = nvme_admin_async_event;
+		/* Note: core layer may overwrite the sqe.command_id value */
 		sqe->common.command_id = AEN_CMDID_BASE + i;
 	}
 	return 0;
@@ -1644,34 +1718,12 @@ nvme_fc_free_nvme_ctrl(struct nvme_ctrl *nctrl)
 			nvme_fc_free_io_queues(ctrl);
 		}
 
-		nvme_fc_exit_aen_ops(ctrl);
-
 		nvme_fc_destroy_admin_queue(ctrl);
 	}
 
 	nvme_fc_ctrl_put(ctrl);
 }
 
-
-static int
-__nvme_fc_abort_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_fcp_op *op)
-{
-	int state;
-
-	state = atomic_xchg(&op->state, FCPOP_STATE_ABORTED);
-	if (state != FCPOP_STATE_ACTIVE) {
-		atomic_set(&op->state, state);
-		return -ECANCELED; /* fail */
-	}
-
-	ctrl->lport->ops->fcp_abort(&ctrl->lport->localport,
-					&ctrl->rport->remoteport,
-					op->queue->lldd_handle,
-					&op->fcp_req);
-
-	return 0;
-}
-
 enum blk_eh_timer_return
 nvme_fc_timeout(struct request *rq, bool reserved)
 {
@@ -1830,10 +1882,7 @@ nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 	sqe->rw.dptr.sgl.length = cpu_to_le32(data_len);
 	sqe->rw.dptr.sgl.addr = 0;
 
-	/* odd that we set the command_id - should come from nvme-fabrics */
-	WARN_ON_ONCE(sqe->common.command_id != cpu_to_le16(op->rqno));
-
-	if (op->rq) {				/* skipped on aens */
+	if (!(op->flags & FCOP_FLAGS_AEN)) {
 		ret = nvme_fc_map_data(ctrl, op->rq, op);
 		if (ret < 0) {
 			dev_err(queue->ctrl->ctrl.device,
@@ -1850,7 +1899,7 @@ nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 
 	atomic_set(&op->state, FCPOP_STATE_ACTIVE);
 
-	if (op->rq)
+	if (!(op->flags & FCOP_FLAGS_AEN))
 		blk_mq_start_request(op->rq);
 
 	ret = ctrl->lport->ops->fcp_io(&ctrl->lport->localport,
@@ -1967,13 +2016,14 @@ nvme_fc_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
 }
 
 static void
-nvme_fc_complete_rq(struct request *rq)
+__nvme_fc_final_op_cleanup(struct request *rq)
 {
 	struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
 	struct nvme_fc_ctrl *ctrl = op->ctrl;
-	int state;
 
-	state = atomic_xchg(&op->state, FCPOP_STATE_IDLE);
+	atomic_set(&op->state, FCPOP_STATE_IDLE);
+	op->flags &= ~(FCOP_FLAGS_TERMIO | FCOP_FLAGS_RELEASED |
+			FCOP_FLAGS_COMPLETE);
 
 	nvme_cleanup_cmd(rq);
 	nvme_fc_unmap_data(ctrl, rq, op);
@@ -1982,6 +2032,33 @@ nvme_fc_complete_rq(struct request *rq)
 
 }
 
+static void
+nvme_fc_complete_rq(struct request *rq)
+{
+	struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
+	struct nvme_fc_ctrl *ctrl = op->ctrl;
+	unsigned long flags;
+	bool completed = false;
+
+	/*
+	 * the core layer, on controller resets after calling
+	 * nvme_shutdown_ctrl(), calls complete_rq without our
+	 * calling blk_mq_complete_request(), thus there may still
+	 * be live i/o outstanding with the LLDD. Means transport has
+	 * to track complete calls vs fcpio_done calls to know what
+	 * path to take on completes and dones.
+	 */
+	spin_lock_irqsave(&ctrl->lock, flags);
+	if (op->flags & FCOP_FLAGS_COMPLETE)
+		completed = true;
+	else
+		op->flags |= FCOP_FLAGS_RELEASED;
+	spin_unlock_irqrestore(&ctrl->lock, flags);
+
+	if (completed)
+		__nvme_fc_final_op_cleanup(rq);
+}
+
 static const struct blk_mq_ops nvme_fc_mq_ops = {
 	.queue_rq	= nvme_fc_queue_rq,
 	.complete	= nvme_fc_complete_rq,
@@ -2105,25 +2182,32 @@ nvme_fc_terminate_exchange(struct request *req, void *data, bool reserved)
 	struct nvme_ctrl *nctrl = data;
 	struct nvme_fc_ctrl *ctrl = to_fc_ctrl(nctrl);
 	struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(req);
-int status;
+	unsigned long flags;
+	int status;
 
 	if (!blk_mq_request_started(req))
 		return;
 
-	/* this performs an ABTS-LS on the FC exchange for the io */
+	spin_lock_irqsave(&ctrl->lock, flags);
+	op->flags |= FCOP_FLAGS_TERMIO;
+	spin_unlock_irqrestore(&ctrl->lock, flags);
+
 	status = __nvme_fc_abort_op(ctrl, op);
-	/*
-	 * if __nvme_fc_abort_op failed: io wasn't active to abort
-	 * consider it done. Assume completion path already completing
-	 * in parallel
-	 */
-	if (status)
-		/* io wasn't active to abort consider it done */
-		/* assume completion path already completing in parallel */
+	if (status) {
+		/*
+		 * if __nvme_fc_abort_op failed the io wasn't
+		 * active. Thus this call path is running in
+		 * parallel to the io complete. Treat as non-error.
+		 */
+
+		/* back out the flags/counters */
+		spin_lock_irqsave(&ctrl->lock, flags);
+		op->flags &= ~FCOP_FLAGS_TERMIO;
+		spin_unlock_irqrestore(&ctrl->lock, flags);
 		return;
+	}
 }
 
-
 /*
  * This routine stops operation of the controller. Admin and IO queues
  * are stopped, outstanding ios on them terminated, and the nvme ctrl
@@ -2161,6 +2245,9 @@ nvme_fc_shutdown_ctrl(struct nvme_fc_ctrl *ctrl)
 	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
 	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
 				nvme_fc_terminate_exchange, &ctrl->ctrl);
+
+	/* kill the aens as they are a separate path */
+	nvme_fc_abort_aen_ops(ctrl);
 }
 
 /*
@@ -2406,12 +2493,12 @@ __nvme_fc_create_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
 
 	ret = nvme_fc_init_aen_ops(ctrl);
 	if (ret)
-		goto out_exit_aen_ops;
+		goto out_stop_keep_alive;
 
 	if (ctrl->queue_count > 1) {
 		ret = nvme_fc_create_io_queues(ctrl);
 		if (ret)
-			goto out_exit_aen_ops;
+			goto out_stop_keep_alive;
 	}
 
 	spin_lock_irqsave(&ctrl->lock, flags);
@@ -2438,8 +2525,8 @@ __nvme_fc_create_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
 
 	return &ctrl->ctrl;
 
-out_exit_aen_ops:
-	nvme_fc_exit_aen_ops(ctrl);
+out_stop_keep_alive:
+	nvme_stop_keep_alive(&ctrl->ctrl);
 out_remove_admin_queue:
 	/* send a Disconnect(association) LS to fc-nvme target */
 	nvme_fc_xmt_disconnect_assoc(ctrl);