linux/io_uring/rsrc.h

// SPDX-License-Identifier: GPL-2.0
#ifndef IOU_RSRC_H
#define IOU_RSRC_H

#include <net/af_unix.h>

#define IO_RSRC_TAG_TABLE_SHIFT	(PAGE_SHIFT - 3)
#define IO_RSRC_TAG_TABLE_MAX	(1U << IO_RSRC_TAG_TABLE_SHIFT)
#define IO_RSRC_TAG_TABLE_MASK	(IO_RSRC_TAG_TABLE_MAX - 1)

enum {
	IORING_RSRC_FILE		= 0,
	IORING_RSRC_BUFFER		= 1,
};

struct io_rsrc_put {
	struct list_head list;
	u64 tag;
	union {
		void *rsrc;
		struct file *file;
		struct io_mapped_ubuf *buf;
	};
};

typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);

struct io_rsrc_data {
	struct io_ring_ctx		*ctx;

	u64				**tags;
	unsigned int			nr;
	rsrc_put_fn			*do_put;
	atomic_t			refs;
	struct completion		done;
	bool				quiesce;
};

struct io_rsrc_node {
	struct percpu_ref		refs;
	struct list_head		node;
	struct list_head		rsrc_list;
	struct io_rsrc_data		*rsrc_data;
	struct llist_node		llist;
	bool				done;
};

struct io_mapped_ubuf {
	u64		ubuf;
	u64		ubuf_end;
	unsigned int	nr_bvecs;
	unsigned long	acct_pages;
	struct bio_vec	bvec[];
};

void io_rsrc_put_tw(struct callback_head *cb);
void io_rsrc_put_work(struct work_struct *work);
void io_rsrc_refs_refill(struct io_ring_ctx *ctx);
void io_wait_rsrc_data(struct io_rsrc_data *data);
void io_rsrc_node_destroy(struct io_rsrc_node *ref_node);
void io_rsrc_refs_drop(struct io_ring_ctx *ctx);
int io_rsrc_node_switch_start(struct io_ring_ctx *ctx);
int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
			  struct io_rsrc_node *node, void *rsrc);
void io_rsrc_node_switch(struct io_ring_ctx *ctx,
			 struct io_rsrc_data *data_to_kill);

int io_import_fixed(int ddir, struct iov_iter *iter,
			   struct io_mapped_ubuf *imu,
			   u64 buf_addr, size_t len);

void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx);
int io_sqe_buffers_unregister(struct io_ring_ctx *ctx);
int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
			    unsigned int nr_args, u64 __user *tags);
void __io_sqe_files_unregister(struct io_ring_ctx *ctx);
int io_sqe_files_unregister(struct io_ring_ctx *ctx);
int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
			  unsigned nr_args, u64 __user *tags);

int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file);

#if defined(CONFIG_UNIX)
static inline bool io_file_need_scm(struct file *filp)
{
	return !!unix_get_socket(filp);
}
#else
static inline bool io_file_need_scm(struct file *filp)
{
	return false;
}
#endif

static inline int io_scm_file_account(struct io_ring_ctx *ctx,
				      struct file *file)
{
	if (likely(!io_file_need_scm(file)))
		return 0;
	return __io_scm_file_account(ctx, file);
}

int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
			     unsigned nr_args);
int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
			    unsigned size, unsigned type);
int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
			unsigned int size, unsigned int type);

static inline void io_rsrc_put_node(struct io_rsrc_node *node, int nr)
{
	percpu_ref_put_many(&node->refs, nr);
}

static inline void io_req_put_rsrc(struct io_kiocb *req)
{
	if (req->rsrc_node)
		io_rsrc_put_node(req->rsrc_node, 1);
}

static inline void io_req_put_rsrc_locked(struct io_kiocb *req,
					  struct io_ring_ctx *ctx)
	__must_hold(&ctx->uring_lock)
{
	struct io_rsrc_node *node = req->rsrc_node;

	if (node) {
		if (node == ctx->rsrc_node)
			ctx->rsrc_cached_refs++;
		else
			io_rsrc_put_node(node, 1);
	}
}

static inline void io_charge_rsrc_node(struct io_ring_ctx *ctx)
{
	ctx->rsrc_cached_refs--;
	if (unlikely(ctx->rsrc_cached_refs < 0))
		io_rsrc_refs_refill(ctx);
}

static inline void io_req_set_rsrc_node(struct io_kiocb *req,
					struct io_ring_ctx *ctx,
					unsigned int issue_flags)
{
	if (!req->rsrc_node) {
		req->rsrc_node = ctx->rsrc_node;

		if (!(issue_flags & IO_URING_F_UNLOCKED)) {
			lockdep_assert_held(&ctx->uring_lock);

			io_charge_rsrc_node(ctx);
		} else {
			percpu_ref_get(&req->rsrc_node->refs);
		}
	}
}

static inline u64 *io_get_tag_slot(struct io_rsrc_data *data, unsigned int idx)
{
	unsigned int off = idx & IO_RSRC_TAG_TABLE_MASK;
	unsigned int table_idx = idx >> IO_RSRC_TAG_TABLE_SHIFT;

	return &data->tags[table_idx][off];
}

int io_files_update(struct io_kiocb *req, unsigned int issue_flags);
int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);

int __io_account_mem(struct user_struct *user, unsigned long nr_pages);

static inline void __io_unaccount_mem(struct user_struct *user,
				      unsigned long nr_pages)
{
	atomic_long_sub(nr_pages, &user->locked_vm);
}

#endif