[PATCH V4 4/4] nvmet: update AEN list and array at one place

[Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>]

From: Daniel Wagner <dwagner@suse.de>

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().

Signed-off-by: Daniel Wagner <dwagner@suse.de>
[chaitanya.kulkarni@wdc.com
 * Added the code to loop over and clear out outstanding requests
   present in the ctrl->async_event_cmds[] for which aen is not
   generated.
 * Update patch description and title to fit kernel log style.
]
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
Changes from V3:-

1. Remove the sq->ctrl in the nvmet_sq_destroy() and use local ctrl
   variable.
2. Initialize sq->ctrl == NULL instead of local variable.

Changes from V2:-

1. Add helper to clean up the array ctrl->nr_async_event_cmds[]
   nvmet_async_events_free().
2. Use local variable into nvmet_sq_destroy().
3. Call newly added helper nvmet_async_events_free() from
   nvmet_sq_destroy().
4. Update commit log.

Changes from V1:-

1. Generate patch on nvme-5.6 branch.
---
 drivers/nvme/target/core.c | 63 ++++++++++++++++++++++----------------
 1 file changed, 36 insertions(+), 27 deletions(-)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 72938c8e9fcb..002658850aa5 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -129,27 +129,8 @@ 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)
-{
-	struct nvmet_req *req;
-
-	while (1) {
-		mutex_lock(&ctrl->lock);
-		if (!ctrl->nr_async_event_cmds) {
-			mutex_unlock(&ctrl->lock);
-			return;
-		}
-
-		req = ctrl->async_event_cmds[--ctrl->nr_async_event_cmds];
-		mutex_unlock(&ctrl->lock);
-		nvmet_req_complete(req, NVME_SC_INTERNAL | NVME_SC_DNR);
-	}
-}
-
-static void nvmet_async_event_work(struct work_struct *work)
+static void nvmet_async_events_process(struct nvmet_ctrl *ctrl, u16 status)
 {
-	struct nvmet_ctrl *ctrl =
-		container_of(work, struct nvmet_ctrl, async_event_work);
 	struct nvmet_async_event *aen;
 	struct nvmet_req *req;
 
@@ -159,20 +140,43 @@ static void nvmet_async_event_work(struct work_struct *work)
 				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];
-		nvmet_set_result(req, nvmet_async_event_result(aen));
+		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, 0);
+		nvmet_req_complete(req, status);
 	}
 }
 
+static void nvmet_async_events_free(struct nvmet_ctrl *ctrl)
+{
+	struct nvmet_req *req;
+
+	mutex_lock(&ctrl->lock);
+	while (ctrl->nr_async_event_cmds) {
+		req = ctrl->async_event_cmds[--ctrl->nr_async_event_cmds];
+		mutex_unlock(&ctrl->lock);
+		nvmet_req_complete(req, NVME_SC_INTERNAL | NVME_SC_DNR);
+		mutex_lock(&ctrl->lock);
+	}
+	mutex_unlock(&ctrl->lock);
+}
+
+static void nvmet_async_event_work(struct work_struct *work)
+{
+	struct nvmet_ctrl *ctrl =
+		container_of(work, struct nvmet_ctrl, async_event_work);
+
+	nvmet_async_events_process(ctrl, 0);
+}
+
 void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
 		u8 event_info, u8 log_page)
 {
@@ -752,19 +756,24 @@ 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 */
 	}
 }
-- 
2.22.1


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