1 files changed, 205 insertions, 0 deletions
diff --git a/fs/fuse/dev_uring_i.h b/fs/fuse/dev_uring_i.h
new file mode 100644
index 000000000000..2102b3d0c1ae
--- /dev/null
+++ b/fs/fuse/dev_uring_i.h
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * FUSE: Filesystem in Userspace
+ * Copyright (c) 2023-2024 DataDirect Networks.
+ */
+
+#ifndef _FS_FUSE_DEV_URING_I_H
+#define _FS_FUSE_DEV_URING_I_H
+
+#include "fuse_i.h"
+
+#ifdef CONFIG_FUSE_IO_URING
+
+#define FUSE_URING_TEARDOWN_TIMEOUT (5 * HZ)
+#define FUSE_URING_TEARDOWN_INTERVAL (HZ/20)
+
+enum fuse_ring_req_state {
+	FRRS_INVALID = 0,
+
+	/* The ring entry received from userspace and it is being processed */
+	FRRS_COMMIT,
+
+	/* The ring entry is waiting for new fuse requests */
+	FRRS_AVAILABLE,
+
+	/* The ring entry got assigned a fuse req */
+	FRRS_FUSE_REQ,
+
+	/* The ring entry is in or on the way to user space */
+	FRRS_USERSPACE,
+
+	/* The ring entry is in teardown */
+	FRRS_TEARDOWN,
+
+	/* The ring entry is released, but not freed yet */
+	FRRS_RELEASED,
+};
+
+/** A fuse ring entry, part of the ring queue */
+struct fuse_ring_ent {
+	/* userspace buffer */
+	struct fuse_uring_req_header __user *headers;
+	void __user *payload;
+
+	/* the ring queue that owns the request */
+	struct fuse_ring_queue *queue;
+
+	/* fields below are protected by queue->lock */
+
+	struct io_uring_cmd *cmd;
+
+	struct list_head list;
+
+	enum fuse_ring_req_state state;
+
+	struct fuse_req *fuse_req;
+};
+
+struct fuse_ring_queue {
+	/*
+	 * back pointer to the main fuse uring structure that holds this
+	 * queue
+	 */
+	struct fuse_ring *ring;
+
+	/* queue id, corresponds to the cpu core */
+	unsigned int qid;
+
+	/*
+	 * queue lock, taken when any value in the queue changes _and_ also
+	 * a ring entry state changes.
+	 */
+	spinlock_t lock;
+
+	/* available ring entries (struct fuse_ring_ent) */
+	struct list_head ent_avail_queue;
+
+	/*
+	 * entries in the process of being committed or in the process
+	 * to be sent to userspace
+	 */
+	struct list_head ent_w_req_queue;
+	struct list_head ent_commit_queue;
+
+	/* entries in userspace */
+	struct list_head ent_in_userspace;
+
+	/* entries that are released */
+	struct list_head ent_released;
+
+	/* fuse requests waiting for an entry slot */
+	struct list_head fuse_req_queue;
+
+	/* background fuse requests */
+	struct list_head fuse_req_bg_queue;
+
+	struct fuse_pqueue fpq;
+
+	unsigned int active_background;
+
+	bool stopped;
+};
+
+/**
+ * Describes if uring is for communication and holds alls the data needed
+ * for uring communication
+ */
+struct fuse_ring {
+	/* back pointer */
+	struct fuse_conn *fc;
+
+	/* number of ring queues */
+	size_t nr_queues;
+
+	/* maximum payload/arg size */
+	size_t max_payload_sz;
+
+	struct fuse_ring_queue **queues;
+
+	/*
+	 * Log ring entry states on stop when entries cannot be released
+	 */
+	unsigned int stop_debug_log : 1;
+
+	wait_queue_head_t stop_waitq;
+
+	/* async tear down */
+	struct delayed_work async_teardown_work;
+
+	/* log */
+	unsigned long teardown_time;
+
+	atomic_t queue_refs;
+
+	bool ready;
+};
+
+bool fuse_uring_enabled(void);
+void fuse_uring_destruct(struct fuse_conn *fc);
+void fuse_uring_stop_queues(struct fuse_ring *ring);
+void fuse_uring_abort_end_requests(struct fuse_ring *ring);
+int fuse_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags);
+void fuse_uring_queue_fuse_req(struct fuse_iqueue *fiq, struct fuse_req *req);
+bool fuse_uring_queue_bq_req(struct fuse_req *req);
+
+static inline void fuse_uring_abort(struct fuse_conn *fc)
+{
+	struct fuse_ring *ring = fc->ring;
+
+	if (ring == NULL)
+		return;
+
+	if (atomic_read(&ring->queue_refs) > 0) {
+		fuse_uring_abort_end_requests(ring);
+		fuse_uring_stop_queues(ring);
+	}
+}
+
+static inline void fuse_uring_wait_stopped_queues(struct fuse_conn *fc)
+{
+	struct fuse_ring *ring = fc->ring;
+
+	if (ring)
+		wait_event(ring->stop_waitq,
+			   atomic_read(&ring->queue_refs) == 0);
+}
+
+static inline bool fuse_uring_ready(struct fuse_conn *fc)
+{
+	return fc->ring && fc->ring->ready;
+}
+
+#else /* CONFIG_FUSE_IO_URING */
+
+struct fuse_ring;
+
+static inline void fuse_uring_create(struct fuse_conn *fc)
+{
+}
+
+static inline void fuse_uring_destruct(struct fuse_conn *fc)
+{
+}
+
+static inline bool fuse_uring_enabled(void)
+{
+	return false;
+}
+
+static inline void fuse_uring_abort(struct fuse_conn *fc)
+{
+}
+
+static inline void fuse_uring_wait_stopped_queues(struct fuse_conn *fc)
+{
+}
+
+static inline bool fuse_uring_ready(struct fuse_conn *fc)
+{
+	return false;
+}
+
+#endif /* CONFIG_FUSE_IO_URING */
+
+#endif /* _FS_FUSE_DEV_URING_I_H */