nvmet: update AEN list and array at one place

All async events are enqueued via nvmet_add_async_event() which
updates the ctrl->async_event_cmds[] array and additionally an struct
nvmet_async_event is added to the ctrl->async_events list.

Under normal operations the nvmet_async_event_work() updates again
the ctrl->async_event_cmds and removes the corresponding struct
nvmet_async_event from the list again. Though nvmet_sq_destroy() could
be called which calls nvmet_async_events_free() which only updates the
ctrl->async_event_cmds[] array.

Add new functions nvmet_async_events_process() and
nvmet_async_events_free() to process async events, update an array and
the list.

When we destroy submission queue after clearing the aen present on
the ctrl->async list we also loop over ctrl->async_event_cmds[] for
any requests posted by the host for which we don't have the AEN in
the ctrl->async_events list by calling nvmet_async_event_process()
and nvmet_async_events_free().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
[chaitanya.kulkarni@wdc.com
 * Loop over and clear out outstanding requests
 * Update changelog
]
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/target/core.c

@@ -129,48 +129,52 @@ static u32 nvmet_async_event_result(struct nvmet_async_event *aen)
 	return aen->event_type | (aen->event_info << 8) | (aen->log_page << 16);
 }
 
-static void nvmet_async_events_free(struct nvmet_ctrl *ctrl)
+static void nvmet_async_events_process(struct nvmet_ctrl *ctrl, u16 status)
 {
+	struct nvmet_async_event *aen;
 	struct nvmet_req *req;
 
 	while (1) {
 		mutex_lock(&ctrl->lock);
-		if (!ctrl->nr_async_event_cmds) {
+		aen = list_first_entry_or_null(&ctrl->async_events,
+				struct nvmet_async_event, entry);
+		if (!aen || !ctrl->nr_async_event_cmds) {
 			mutex_unlock(&ctrl->lock);
-			return;
+			break;
 		}
 
 		req = ctrl->async_event_cmds[--ctrl->nr_async_event_cmds];
+		if (status == 0)
+			nvmet_set_result(req, nvmet_async_event_result(aen));
+
+		list_del(&aen->entry);
+		kfree(aen);
+
 		mutex_unlock(&ctrl->lock);
-		nvmet_req_complete(req, NVME_SC_INTERNAL | NVME_SC_DNR);
+		nvmet_req_complete(req, status);
 	}
 }
 
-static void nvmet_async_event_work(struct work_struct *work)
+static void nvmet_async_events_free(struct nvmet_ctrl *ctrl)
 {
-	struct nvmet_ctrl *ctrl =
-		container_of(work, struct nvmet_ctrl, async_event_work);
-	struct nvmet_async_event *aen;
 	struct nvmet_req *req;
 
-	while (1) {
 	mutex_lock(&ctrl->lock);
-		aen = list_first_entry_or_null(&ctrl->async_events,
-				struct nvmet_async_event, entry);
-		if (!aen || !ctrl->nr_async_event_cmds) {
+	while (ctrl->nr_async_event_cmds) {
+		req = ctrl->async_event_cmds[--ctrl->nr_async_event_cmds];
 		mutex_unlock(&ctrl->lock);
-			return;
+		nvmet_req_complete(req, NVME_SC_INTERNAL | NVME_SC_DNR);
+		mutex_lock(&ctrl->lock);
 	}
+	mutex_unlock(&ctrl->lock);
+}
 
-		req = ctrl->async_event_cmds[--ctrl->nr_async_event_cmds];
-		nvmet_set_result(req, nvmet_async_event_result(aen));
-
-		list_del(&aen->entry);
-		kfree(aen);
+static void nvmet_async_event_work(struct work_struct *work)
+{
+	struct nvmet_ctrl *ctrl =
+		container_of(work, struct nvmet_ctrl, async_event_work);
 
-		mutex_unlock(&ctrl->lock);
-		nvmet_req_complete(req, 0);
-	}
+	nvmet_async_events_process(ctrl, 0);
 }
 
 void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
@@ -753,19 +757,24 @@ static void nvmet_confirm_sq(struct percpu_ref *ref)
 
 void nvmet_sq_destroy(struct nvmet_sq *sq)
 {
+	u16 status = NVME_SC_INTERNAL | NVME_SC_DNR;
+	struct nvmet_ctrl *ctrl = sq->ctrl;
+
 	/*
 	 * If this is the admin queue, complete all AERs so that our
 	 * queue doesn't have outstanding requests on it.
 	 */
-	if (sq->ctrl && sq->ctrl->sqs && sq->ctrl->sqs[0] == sq)
-		nvmet_async_events_free(sq->ctrl);
+	if (ctrl && ctrl->sqs && ctrl->sqs[0] == sq) {
+		nvmet_async_events_process(ctrl, status);
+		nvmet_async_events_free(ctrl);
+	}
 	percpu_ref_kill_and_confirm(&sq->ref, nvmet_confirm_sq);
 	wait_for_completion(&sq->confirm_done);
 	wait_for_completion(&sq->free_done);
 	percpu_ref_exit(&sq->ref);
 
-	if (sq->ctrl) {
-		nvmet_ctrl_put(sq->ctrl);
+	if (ctrl) {
+		nvmet_ctrl_put(ctrl);
 		sq->ctrl = NULL; /* allows reusing the queue later */
 	}
 }