[thirdparty/kernel/linux.git] / io_uring / kbuf.h

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

#include <uapi/linux/io_uring.h>

struct io_buffer_list {
	/*
	 * If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
	 * then these are classic provided buffers and ->buf_list is used.
	 */
	union {
		struct list_head buf_list;
		struct {
			struct page **buf_pages;
			struct io_uring_buf_ring *buf_ring;
		};
		struct rcu_head rcu;
	};
	__u16 bgid;

	/* below is for ring provided buffers */
	__u16 buf_nr_pages;
	__u16 nr_entries;
	__u16 head;
	__u16 mask;

	atomic_t refs;

	/* ring mapped provided buffers */
	__u8 is_buf_ring;
	/* ring mapped provided buffers, but mmap'ed by application */
	__u8 is_mmap;
};

struct io_buffer {
	struct list_head list;
	__u64 addr;
	__u32 len;
	__u16 bid;
	__u16 bgid;
};

void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
			      unsigned int issue_flags);
void io_destroy_buffers(struct io_ring_ctx *ctx);

int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);

int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);

int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg);

void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);

void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);

bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);

void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl);
struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
				      unsigned long bgid);

static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
{
	/*
	 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
	 * the flag and hence ensure that bl->head doesn't get incremented.
	 * If the tail has already been incremented, hang on to it.
	 * The exception is partial io, that case we should increment bl->head
	 * to monopolize the buffer.
	 */
	if (req->buf_list) {
		req->buf_index = req->buf_list->bgid;
		req->flags &= ~REQ_F_BUFFER_RING;
		return true;
	}
	return false;
}

static inline bool io_do_buffer_select(struct io_kiocb *req)
{
	if (!(req->flags & REQ_F_BUFFER_SELECT))
		return false;
	return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
}

static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
{
	if (req->flags & REQ_F_BL_NO_RECYCLE)
		return false;
	if (req->flags & REQ_F_BUFFER_SELECTED)
		return io_kbuf_recycle_legacy(req, issue_flags);
	if (req->flags & REQ_F_BUFFER_RING)
		return io_kbuf_recycle_ring(req);
	return false;
}

static inline void __io_put_kbuf_ring(struct io_kiocb *req)
{
	if (req->buf_list) {
		req->buf_index = req->buf_list->bgid;
		req->buf_list->head++;
	}
	req->flags &= ~REQ_F_BUFFER_RING;
}

static inline void __io_put_kbuf_list(struct io_kiocb *req,
				      struct list_head *list)
{
	if (req->flags & REQ_F_BUFFER_RING) {
		__io_put_kbuf_ring(req);
	} else {
		req->buf_index = req->kbuf->bgid;
		list_add(&req->kbuf->list, list);
		req->flags &= ~REQ_F_BUFFER_SELECTED;
	}
}

static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
{
	unsigned int ret;

	lockdep_assert_held(&req->ctx->completion_lock);

	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
		return 0;

	ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
	__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
	return ret;
}

static inline unsigned int io_put_kbuf(struct io_kiocb *req,
				       unsigned issue_flags)
{
	unsigned int ret;

	if (!(req->flags & (REQ_F_BUFFER_RING | REQ_F_BUFFER_SELECTED)))
		return 0;

	ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
	if (req->flags & REQ_F_BUFFER_RING)
		__io_put_kbuf_ring(req);
	else
		__io_put_kbuf(req, issue_flags);
	return ret;
}
#endif
Commit	Line	Data
3b77495a JA	1	// SPDX-License-Identifier: GPL-2.0
	2	#ifndef IOU_KBUF_H
	3	#define IOU_KBUF_H
	4
	5	#include <uapi/linux/io_uring.h>
	6
	7	struct io_buffer_list {
	8	/*
	9	* If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
	10	* then these are classic provided buffers and ->buf_list is used.
	11	*/
	12	union {
	13	struct list_head buf_list;
	14	struct {
	15	struct page **buf_pages;
	16	struct io_uring_buf_ring *buf_ring;
	17	};
5cf4f52e	18	struct rcu_head rcu;
3b77495a JA	19	};
	20	__u16 bgid;
	21
	22	/* below is for ring provided buffers */
	23	__u16 buf_nr_pages;
	24	__u16 nr_entries;
	25	__u16 head;
	26	__u16 mask;
25a2c188	27
6b69c4ab JA	28	atomic_t refs;
6b69c4ab JA	29
25a2c188	30	/* ring mapped provided buffers */
9219e4a9	31	__u8 is_buf_ring;
c56e022c JA	32	/* ring mapped provided buffers, but mmap'ed by application */
c56e022c JA	33	__u8 is_mmap;
3b77495a JA	34	};
	35
	36	struct io_buffer {
	37	struct list_head list;
	38	__u64 addr;
	39	__u32 len;
	40	__u16 bid;
	41	__u16 bgid;
	42	};
	43
	44	void __user io_buffer_select(struct io_kiocb req, size_t *len,
	45	unsigned int issue_flags);
3b77495a JA	46	void io_destroy_buffers(struct io_ring_ctx *ctx);
	47
	48	int io_remove_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	49	int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
	50
	51	int io_provide_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	52	int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
	53
	54	int io_register_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
	55	int io_unregister_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
d293b1a8	56	int io_register_pbuf_status(struct io_ring_ctx ctx, void __user arg);
3b77495a	57
c392cbec JA	58	void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);
c392cbec JA	59
8435c6f3	60	void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
53ccf69b	61
89d528ba	62	bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
795bbbc8	63
561e4f94 JA	64	void io_put_bl(struct io_ring_ctx ctx, struct io_buffer_list bl);
	65	struct io_buffer_list io_pbuf_get_bl(struct io_ring_ctx ctx,
	66	unsigned long bgid);
c56e022c	67
89d528ba	68	static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
795bbbc8 HX	69	{
	70	/*
	71	* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
	72	* the flag and hence ensure that bl->head doesn't get incremented.
	73	* If the tail has already been incremented, hang on to it.
	74	* The exception is partial io, that case we should increment bl->head
	75	* to monopolize the buffer.
	76	*/
	77	if (req->buf_list) {
186daf23 JA	78	req->buf_index = req->buf_list->bgid;
	79	req->flags &= ~REQ_F_BUFFER_RING;
	80	return true;
795bbbc8	81	}
89d528ba	82	return false;
795bbbc8	83	}
024b8fde	84
3b77495a JA	85	static inline bool io_do_buffer_select(struct io_kiocb *req)
	86	{
	87	if (!(req->flags & REQ_F_BUFFER_SELECT))
	88	return false;
	89	return !(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING));
	90	}
	91
89d528ba	92	static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
3b77495a	93	{
186daf23 JA	94	if (req->flags & REQ_F_BL_NO_RECYCLE)
186daf23 JA	95	return false;
024b8fde	96	if (req->flags & REQ_F_BUFFER_SELECTED)
89d528ba	97	return io_kbuf_recycle_legacy(req, issue_flags);
024b8fde	98	if (req->flags & REQ_F_BUFFER_RING)
89d528ba DY	99	return io_kbuf_recycle_ring(req);
89d528ba DY	100	return false;
3b77495a JA	101	}
3b77495a JA	102
8435c6f3	103	static inline void __io_put_kbuf_ring(struct io_kiocb *req)
3b77495a	104	{
8435c6f3 JA	105	if (req->buf_list) {
	106	req->buf_index = req->buf_list->bgid;
	107	req->buf_list->head++;
	108	}
	109	req->flags &= ~REQ_F_BUFFER_RING;
	110	}
32f3c434	111
8435c6f3 JA	112	static inline void __io_put_kbuf_list(struct io_kiocb *req,
	113	struct list_head *list)
	114	{
3b77495a	115	if (req->flags & REQ_F_BUFFER_RING) {
8435c6f3	116	__io_put_kbuf_ring(req);
3b77495a	117	} else {
32f3c434	118	req->buf_index = req->kbuf->bgid;
3b77495a JA	119	list_add(&req->kbuf->list, list);
	120	req->flags &= ~REQ_F_BUFFER_SELECTED;
	121	}
3b77495a JA	122	}
	123
	124	static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
	125	{
8435c6f3 JA	126	unsigned int ret;
8435c6f3 JA	127
3b77495a JA	128	lockdep_assert_held(&req->ctx->completion_lock);
	129
	130	if (!(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING)))
	131	return 0;
8435c6f3 JA	132
	133	ret = IORING_CQE_F_BUFFER \| (req->buf_index << IORING_CQE_BUFFER_SHIFT);
	134	__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
	135	return ret;
3b77495a JA	136	}
	137
	138	static inline unsigned int io_put_kbuf(struct io_kiocb *req,
	139	unsigned issue_flags)
	140	{
8435c6f3	141	unsigned int ret;
3b77495a	142
8435c6f3	143	if (!(req->flags & (REQ_F_BUFFER_RING \| REQ_F_BUFFER_SELECTED)))
3b77495a	144	return 0;
8435c6f3 JA	145
	146	ret = IORING_CQE_F_BUFFER \| (req->buf_index << IORING_CQE_BUFFER_SHIFT);
	147	if (req->flags & REQ_F_BUFFER_RING)
	148	__io_put_kbuf_ring(req);
	149	else
	150	__io_put_kbuf(req, issue_flags);
	151	return ret;
3b77495a JA	152	}
3b77495a JA	153	#endif