[PATCH 1/5] fuse: {io-uring} Add queue length counters

[Bernd Schubert <bschubert@xxxxxxx>]

This is another preparation and will be used for decision
which queue to add a request to.
---
 fs/fuse/dev_uring.c   | 17 +++++++++++++++--
 fs/fuse/dev_uring_i.h |  3 +++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
index 249b210becb1cc2b40ae7b2fdf3a57dc57eaac42..2f2f7ff5e95a63a4df76f484d30cce1077b29123 100644
--- a/fs/fuse/dev_uring.c
+++ b/fs/fuse/dev_uring.c
@@ -85,13 +85,13 @@ static void fuse_uring_req_end(struct fuse_ring_ent *ent, struct fuse_req *req,
 	lockdep_assert_not_held(&queue->lock);
 	spin_lock(&queue->lock);
 	ent->fuse_req = NULL;
+	queue->nr_reqs--;
 	if (test_bit(FR_BACKGROUND, &req->flags)) {
 		queue->active_background--;
 		spin_lock(&fc->bg_lock);
 		fuse_uring_flush_bg(queue);
 		spin_unlock(&fc->bg_lock);
 	}
-
 	spin_unlock(&queue->lock);
 
 	if (error)
@@ -111,6 +111,7 @@ static void fuse_uring_abort_end_queue_requests(struct fuse_ring_queue *queue)
 	list_for_each_entry(req, &queue->fuse_req_queue, list)
 		clear_bit(FR_PENDING, &req->flags);
 	list_splice_init(&queue->fuse_req_queue, &req_list);
+	queue->nr_reqs = 0;
 	spin_unlock(&queue->lock);
 
 	/* must not hold queue lock to avoid order issues with fi->lock */
@@ -1280,10 +1281,13 @@ void fuse_uring_queue_fuse_req(struct fuse_iqueue *fiq, struct fuse_req *req)
 	req->ring_queue = queue;
 	ent = list_first_entry_or_null(&queue->ent_avail_queue,
 				       struct fuse_ring_ent, list);
+	queue->nr_reqs++;
+
 	if (ent)
 		fuse_uring_add_req_to_ring_ent(ent, req);
 	else
 		list_add_tail(&req->list, &queue->fuse_req_queue);
+
 	spin_unlock(&queue->lock);
 
 	if (ent)
@@ -1319,6 +1323,7 @@ bool fuse_uring_queue_bq_req(struct fuse_req *req)
 	set_bit(FR_URING, &req->flags);
 	req->ring_queue = queue;
 	list_add_tail(&req->list, &queue->fuse_req_bg_queue);
+	queue->nr_reqs++;
 
 	ent = list_first_entry_or_null(&queue->ent_avail_queue,
 				       struct fuse_ring_ent, list);
@@ -1351,8 +1356,16 @@ bool fuse_uring_queue_bq_req(struct fuse_req *req)
 bool fuse_uring_remove_pending_req(struct fuse_req *req)
 {
 	struct fuse_ring_queue *queue = req->ring_queue;
+	bool removed = fuse_remove_pending_req(req, &queue->lock);
 
-	return fuse_remove_pending_req(req, &queue->lock);
+	if (removed) {
+		/* Update counters after successful removal */
+		spin_lock(&queue->lock);
+		queue->nr_reqs--;
+		spin_unlock(&queue->lock);
+	}
+
+	return removed;
 }
 
 static const struct fuse_iqueue_ops fuse_io_uring_ops = {
diff --git a/fs/fuse/dev_uring_i.h b/fs/fuse/dev_uring_i.h
index 51a563922ce14158904a86c248c77767be4fe5ae..c63bed9f863d53d4ac2bed7bfbda61941cd99083 100644
--- a/fs/fuse/dev_uring_i.h
+++ b/fs/fuse/dev_uring_i.h
@@ -94,6 +94,9 @@ struct fuse_ring_queue {
 	/* background fuse requests */
 	struct list_head fuse_req_bg_queue;
 
+	/* number of requests queued or in userspace */
+	unsigned int nr_reqs;
+
 	struct fuse_pqueue fpq;
 
 	unsigned int active_background;

-- 
2.43.0