path: root/fs/fuse/dev_uring.c

// SPDX-License-Identifier: GPL-2.0
/*
 * FUSE: Filesystem in Userspace
 * Copyright (c) 2023-2024 DataDirect Networks.
 */

#include "fuse_i.h"
#include "dev_uring_i.h"
#include "fuse_dev_i.h"
#include "fuse_trace.h"

#include <linux/fs.h>
#include <linux/io_uring/cmd.h>

static bool __read_mostly enable_uring;
module_param(enable_uring, bool, 0644);
MODULE_PARM_DESC(enable_uring,
		 "Enable userspace communication through io-uring");

#define FUSE_URING_IOV_SEGS 2 /* header and payload */


bool fuse_uring_enabled(void)
{
	return enable_uring;
}

struct fuse_uring_pdu {
	struct fuse_ring_ent *ent;
};

static const struct fuse_iqueue_ops fuse_io_uring_ops;

static void uring_cmd_set_ring_ent(struct io_uring_cmd *cmd,
				   struct fuse_ring_ent *ring_ent)
{
	struct fuse_uring_pdu *pdu =
		io_uring_cmd_to_pdu(cmd, struct fuse_uring_pdu);

	pdu->ent = ring_ent;
}

static struct fuse_ring_ent *uring_cmd_to_ring_ent(struct io_uring_cmd *cmd)
{
	struct fuse_uring_pdu *pdu =
		io_uring_cmd_to_pdu(cmd, struct fuse_uring_pdu);

	return pdu->ent;
}

static void fuse_uring_flush_bg(struct fuse_ring_queue *queue)
{
	struct fuse_ring *ring = queue->ring;
	struct fuse_conn *fc = ring->fc;

	lockdep_assert_held(&queue->lock);
	lockdep_assert_held(&fc->bg_lock);

	/*
	 * Allow one bg request per queue, ignoring global fc limits.
	 * This prevents a single queue from consuming all resources and
	 * eliminates the need for remote queue wake-ups when global
	 * limits are met but this queue has no more waiting requests.
	 */
	while ((fc->active_background < fc->max_background ||
		!queue->active_background) &&
	       (!list_empty(&queue->fuse_req_bg_queue))) {
		struct fuse_req *req;

		req = list_first_entry