[isci-rnc PATCH v1 20/37] isci: Implement waiting for suspend in the abort path.

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From: Jeff Skirvin <jeffrey.d.skirvin@xxxxxxxxx>

In order to prevent a device from receiving an I/O request while still
in an RNC suspending or resuming state (and therefore failing that
I/O back to libsas with a reset required status) wait for the RNC state
change before proceding in the abort path.

Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/scsi/isci/remote_device.c       |   44 +++++++++++++++++++++++--------
 drivers/scsi/isci/remote_device.h       |    6 +---
 drivers/scsi/isci/remote_node_context.c |   21 +++++++++++++++
 drivers/scsi/isci/remote_node_context.h |    3 ++
 drivers/scsi/isci/task.c                |   14 +++++-----
 5 files changed, 66 insertions(+), 22 deletions(-)

diff --git a/drivers/scsi/isci/remote_device.c b/drivers/scsi/isci/remote_device.c
index 86aca11..acc94a4 100644
--- a/drivers/scsi/isci/remote_device.c
+++ b/drivers/scsi/isci/remote_device.c
@@ -137,6 +137,14 @@ static enum sci_status sci_remote_device_terminate_reqs_checkabort(
 	return status;
 }
 
+static bool isci_compare_suspendcount(
+	struct isci_remote_device *idev,
+	u32 localcount)
+{
+	smp_rmb();
+	return localcount != idev->rnc.suspend_count;
+}
+
 enum sci_status isci_remote_device_terminate_requests(
 	struct isci_host *ihost,
 	struct isci_remote_device *idev,
@@ -144,31 +152,44 @@ enum sci_status isci_remote_device_terminate_requests(
 {
 	enum sci_status status = SCI_SUCCESS;
 	unsigned long flags;
+	u32 rnc_suspend_count;
 
 	spin_lock_irqsave(&ihost->scic_lock, flags);
+
 	if (isci_get_device(idev) == NULL) {
 		dev_dbg(&ihost->pdev->dev, "%s: failed isci_get_device(idev=%p)\n",
 			__func__, idev);
 		spin_unlock_irqrestore(&ihost->scic_lock, flags);
 		status = SCI_FAILURE;
 	} else {
+		/* If already suspended, don't wait for another suspension. */
+		smp_rmb();
+		rnc_suspend_count
+			= sci_remote_node_context_is_suspended(&idev->rnc)
+				? 0 : idev->rnc.suspend_count;
+
 		dev_dbg(&ihost->pdev->dev,
 			"%s: idev=%p, ireq=%p; started_request_count=%d, "
+				"rnc_suspend_count=%d, rnc.suspend_count=%d"
 				"about to wait\n",
-			__func__, idev, ireq, idev->started_request_count);
+			__func__, idev, ireq, idev->started_request_count,
+			rnc_suspend_count, idev->rnc.suspend_count);
 		if (ireq) {
 			/* Terminate a specific TC. */
 			sci_remote_device_terminate_req(ihost, idev, 0, ireq);
 			spin_unlock_irqrestore(&ihost->scic_lock, flags);
-			wait_event(ihost->eventq, !test_bit(IREQ_ACTIVE,
-							    &ireq->flags));
-
+			wait_event(ihost->eventq,
+				   (isci_compare_suspendcount(idev,
+							      rnc_suspend_count)
+				    && !test_bit(IREQ_ACTIVE, &ireq->flags)));
 		} else {
 			/* Terminate all TCs. */
 			sci_remote_device_terminate_requests(idev);
 			spin_unlock_irqrestore(&ihost->scic_lock, flags);
 			wait_event(ihost->eventq,
-				   idev->started_request_count == 0);
+				   (isci_compare_suspendcount(idev,
+							      rnc_suspend_count)
+				    && idev->started_request_count == 0));
 		}
 		dev_dbg(&ihost->pdev->dev, "%s: idev=%p, wait done\n",
 			__func__, idev);
@@ -1234,19 +1255,20 @@ enum sci_status sci_remote_device_resume(
 	return status;
 }
 
-enum sci_status isci_remote_device_resume(
+enum sci_status isci_remote_device_resume_from_abort(
 	struct isci_host *ihost,
-	struct isci_remote_device *idev,
-	scics_sds_remote_node_context_callback cb_fn,
-	void *cb_p)
+	struct isci_remote_device *idev)
 {
 	unsigned long flags;
 	enum sci_status status;
 
 	spin_lock_irqsave(&ihost->scic_lock, flags);
-	status = sci_remote_device_resume(idev, cb_fn, cb_p);
+	/* Preserve any current resume callbacks, for instance from other
+	 * resumptions.
+	 */
+	status = sci_remote_device_resume(idev, idev->rnc.user_callback,
+					  idev->rnc.user_cookie);
 	spin_unlock_irqrestore(&ihost->scic_lock, flags);
-
 	return status;
 }
 /**
diff --git a/drivers/scsi/isci/remote_device.h b/drivers/scsi/isci/remote_device.h
index ef563e5..d1d1892 100644
--- a/drivers/scsi/isci/remote_device.h
+++ b/drivers/scsi/isci/remote_device.h
@@ -357,11 +357,9 @@ enum sci_status sci_remote_device_resume(
 	scics_sds_remote_node_context_callback cb_fn,
 	void *cb_p);
 
-enum sci_status isci_remote_device_resume(
+enum sci_status isci_remote_device_resume_from_abort(
 	struct isci_host *ihost,
-	struct isci_remote_device *idev,
-	scics_sds_remote_node_context_callback cb_fn,
-	void *cb_p);
+	struct isci_remote_device *idev);
 
 enum sci_status isci_remote_device_reset(
 	struct isci_host *ihost,
diff --git a/drivers/scsi/isci/remote_node_context.c b/drivers/scsi/isci/remote_node_context.c
index 48565de..77c8b51 100644
--- a/drivers/scsi/isci/remote_node_context.c
+++ b/drivers/scsi/isci/remote_node_context.c
@@ -90,6 +90,15 @@ bool sci_remote_node_context_is_ready(
 	return false;
 }
 
+bool sci_remote_node_context_is_suspended(struct sci_remote_node_context *sci_rnc)
+{
+	u32 current_state = sci_rnc->sm.current_state_id;
+
+	if (current_state == SCI_RNC_TX_RX_SUSPENDED)
+		return true;
+	return false;
+}
+
 static union scu_remote_node_context *sci_rnc_by_id(struct isci_host *ihost, u16 id)
 {
 	if (id < ihost->remote_node_entries &&
@@ -339,6 +348,13 @@ static void sci_remote_node_context_tx_rx_suspended_state_enter(struct sci_base_
 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
 	struct isci_remote_device *idev = rnc_to_dev(rnc);
 	struct isci_host *ihost = idev->owning_port->owning_controller;
+	u32 new_count = rnc->suspend_count + 1;
+
+	if (new_count == 0)
+		rnc->suspend_count = 1;
+	else
+		rnc->suspend_count = new_count;
+	smp_wmb();
 
 	/* Terminate outstanding requests pending abort. */
 	sci_remote_device_abort_requests_pending_abort(idev);
@@ -634,6 +650,11 @@ enum sci_status sci_remote_node_context_resume(struct sci_remote_node_context *s
 	enum scis_sds_remote_node_context_states state;
 
 	state = sci_rnc->sm.current_state_id;
+	dev_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+		 "%s: state %s, cb_fn = %p, cb_p = %p; dest_state = %d\n",
+		 __func__, rnc_state_name(state), cb_fn, cb_p,
+		 sci_rnc->destination_state);
+
 	switch (state) {
 	case SCI_RNC_INITIAL:
 		if (sci_rnc->remote_node_index == SCIC_SDS_REMOTE_NODE_CONTEXT_INVALID_INDEX)
diff --git a/drivers/scsi/isci/remote_node_context.h b/drivers/scsi/isci/remote_node_context.h
index 9eee304..c61c02e 100644
--- a/drivers/scsi/isci/remote_node_context.h
+++ b/drivers/scsi/isci/remote_node_context.h
@@ -170,6 +170,7 @@ struct sci_remote_node_context {
 	 */
 	u32 suspend_type;
 	enum sci_remote_node_suspension_reasons suspend_reason;
+	u32 suspend_count;
 
 	/**
 	 * This field is true if the remote node context is resuming from its current
@@ -203,6 +204,8 @@ void sci_remote_node_context_construct(struct sci_remote_node_context *rnc,
 bool sci_remote_node_context_is_ready(
 	struct sci_remote_node_context *sci_rnc);
 
+bool sci_remote_node_context_is_suspended(struct sci_remote_node_context *sci_rnc);
+
 enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_context *sci_rnc,
 							   u32 event_code);
 enum sci_status sci_remote_node_context_destruct(struct sci_remote_node_context *sci_rnc,
diff --git a/drivers/scsi/isci/task.c b/drivers/scsi/isci/task.c
index 5d738fd..c1c6dd0 100644
--- a/drivers/scsi/isci/task.c
+++ b/drivers/scsi/isci/task.c
@@ -317,11 +317,11 @@ static int isci_task_execute_tmf(struct isci_host *ihost,
 		spin_unlock_irqrestore(&ihost->scic_lock, flags);
 		goto err_tci;
 	}
-	/* The RNC must be unsuspended before the TMF can get a response. */
-	sci_remote_device_resume(idev, NULL, NULL);
-
 	spin_unlock_irqrestore(&ihost->scic_lock, flags);
 
+	/* The RNC must be unsuspended before the TMF can get a response. */
+	isci_remote_device_resume_from_abort(ihost, idev);
+
 	/* Wait for the TMF to complete, or a timeout. */
 	timeleft = wait_for_completion_timeout(&completion,
 					       msecs_to_jiffies(timeout_ms));
@@ -554,11 +554,11 @@ int isci_task_abort_task(struct sas_task *task)
 	    sas_protocol_ata(task->task_proto) ||
 	    test_bit(IREQ_COMPLETE_IN_TARGET, &old_request->flags)) {
 
-		/* No task to send, so explicitly resume the device here */
-		sci_remote_device_resume(idev, NULL, NULL);
-
 		spin_unlock_irqrestore(&ihost->scic_lock, flags);
 
+		/* No task to send, so explicitly resume the device here */
+		isci_remote_device_resume_from_abort(ihost, idev);
+
 		dev_warn(&ihost->pdev->dev,
 			 "%s: %s request"
 				 " or complete_in_target (%d), thus no TMF\n",
@@ -757,7 +757,7 @@ static int isci_reset_device(struct isci_host *ihost,
 		reset_stat = sas_phy_reset(phy, !dev_is_sata(dev));
 
 	/* Explicitly resume the RNC here, since there was no task sent. */
-	isci_remote_device_resume(ihost, idev, NULL, NULL);
+	isci_remote_device_resume_from_abort(ihost, idev);
 
 	dev_dbg(&ihost->pdev->dev, "%s: idev %p complete, reset_stat=%d.\n",
 		__func__, idev, reset_stat);

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