[linux-block.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;
};

enum {
	/* can alloc a bigger vec */
	KBUF_MODE_EXPAND	= 1,
	/* if bigger vec allocated, free old one */
	KBUF_MODE_FREE		= 2,
};

struct buf_sel_arg {
	struct iovec *iovs;
	size_t out_len;
	size_t max_len;
	int nr_iovs;
	int mode;
};

void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
			      unsigned int issue_flags);
int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg,
		      unsigned int issue_flags);
int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg);
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_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);
int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma);

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|REQ_F_BUFFERS_COMMIT);
		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, int nr)
{
	struct io_buffer_list *bl = req->buf_list;

	if (bl) {
		if (req->flags & REQ_F_BUFFERS_COMMIT) {
			bl->head += nr;
			req->flags &= ~REQ_F_BUFFERS_COMMIT;
		}
		req->buf_index = bl->bgid;
	}
	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, 1);
	} else {
		req->buf_index = req->kbuf->bgid;
		list_add(&req->kbuf->list, list);
		req->flags &= ~REQ_F_BUFFER_SELECTED;
	}
}

static inline void io_kbuf_drop(struct io_kiocb *req)
{
	lockdep_assert_held(&req->ctx->completion_lock);

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

	__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
}

static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int nbufs,
					  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, nbufs);
	else
		__io_put_kbuf(req, issue_flags);
	return ret;
}

static inline unsigned int io_put_kbuf(struct io_kiocb *req,
				       unsigned issue_flags)
{
	return __io_put_kbufs(req, 1, issue_flags);
}

static inline unsigned int io_put_kbufs(struct io_kiocb *req, int nbufs,
					unsigned issue_flags)
{
	return __io_put_kbufs(req, nbufs, issue_flags);
}
#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
35c8711c JA	44	enum {
	45	/* can alloc a bigger vec */
	46	KBUF_MODE_EXPAND = 1,
	47	/* if bigger vec allocated, free old one */
	48	KBUF_MODE_FREE = 2,
	49	};
	50
	51	struct buf_sel_arg {
	52	struct iovec *iovs;
	53	size_t out_len;
	54	size_t max_len;
	55	int nr_iovs;
	56	int mode;
	57	};
	58
3b77495a JA	59	void __user io_buffer_select(struct io_kiocb req, size_t *len,
3b77495a JA	60	unsigned int issue_flags);
35c8711c JA	61	int io_buffers_select(struct io_kiocb req, struct buf_sel_arg arg,
	62	unsigned int issue_flags);
	63	int io_buffers_peek(struct io_kiocb req, struct buf_sel_arg arg);
3b77495a JA	64	void io_destroy_buffers(struct io_ring_ctx *ctx);
	65
	66	int io_remove_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	67	int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
	68
	69	int io_provide_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	70	int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
	71
	72	int io_register_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
	73	int io_unregister_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
d293b1a8	74	int io_register_pbuf_status(struct io_ring_ctx ctx, void __user arg);
3b77495a	75
8435c6f3	76	void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
53ccf69b	77
89d528ba	78	bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
795bbbc8	79
561e4f94 JA	80	void io_put_bl(struct io_ring_ctx ctx, struct io_buffer_list bl);
	81	struct io_buffer_list io_pbuf_get_bl(struct io_ring_ctx ctx,
	82	unsigned long bgid);
87585b05	83	int io_pbuf_mmap(struct file file, struct vm_area_struct vma);
c56e022c	84
89d528ba	85	static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
795bbbc8 HX	86	{
	87	/*
	88	* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
	89	* the flag and hence ensure that bl->head doesn't get incremented.
	90	* If the tail has already been incremented, hang on to it.
	91	* The exception is partial io, that case we should increment bl->head
	92	* to monopolize the buffer.
	93	*/
	94	if (req->buf_list) {
186daf23	95	req->buf_index = req->buf_list->bgid;
35c8711c	96	req->flags &= ~(REQ_F_BUFFER_RING\|REQ_F_BUFFERS_COMMIT);
186daf23	97	return true;
795bbbc8	98	}
89d528ba	99	return false;
795bbbc8	100	}
024b8fde	101
3b77495a JA	102	static inline bool io_do_buffer_select(struct io_kiocb *req)
	103	{
	104	if (!(req->flags & REQ_F_BUFFER_SELECT))
	105	return false;
	106	return !(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING));
	107	}
	108
89d528ba	109	static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
3b77495a	110	{
186daf23 JA	111	if (req->flags & REQ_F_BL_NO_RECYCLE)
186daf23 JA	112	return false;
024b8fde	113	if (req->flags & REQ_F_BUFFER_SELECTED)
89d528ba	114	return io_kbuf_recycle_legacy(req, issue_flags);
024b8fde	115	if (req->flags & REQ_F_BUFFER_RING)
89d528ba DY	116	return io_kbuf_recycle_ring(req);
89d528ba DY	117	return false;
3b77495a JA	118	}
3b77495a JA	119
35c8711c	120	static inline void __io_put_kbuf_ring(struct io_kiocb *req, int nr)
3b77495a	121	{
35c8711c JA	122	struct io_buffer_list *bl = req->buf_list;
	123
	124	if (bl) {
	125	if (req->flags & REQ_F_BUFFERS_COMMIT) {
	126	bl->head += nr;
	127	req->flags &= ~REQ_F_BUFFERS_COMMIT;
	128	}
	129	req->buf_index = bl->bgid;
8435c6f3 JA	130	}
	131	req->flags &= ~REQ_F_BUFFER_RING;
	132	}
32f3c434	133
8435c6f3 JA	134	static inline void __io_put_kbuf_list(struct io_kiocb *req,
	135	struct list_head *list)
	136	{
3b77495a	137	if (req->flags & REQ_F_BUFFER_RING) {
35c8711c	138	__io_put_kbuf_ring(req, 1);
3b77495a	139	} else {
32f3c434	140	req->buf_index = req->kbuf->bgid;
3b77495a JA	141	list_add(&req->kbuf->list, list);
	142	req->flags &= ~REQ_F_BUFFER_SELECTED;
	143	}
3b77495a JA	144	}
3b77495a JA	145
bbbef3e9	146	static inline void io_kbuf_drop(struct io_kiocb *req)
3b77495a JA	147	{
	148	lockdep_assert_held(&req->ctx->completion_lock);
	149
	150	if (!(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING)))
bbbef3e9	151	return;
8435c6f3	152
8435c6f3	153	__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
3b77495a JA	154	}
3b77495a JA	155
35c8711c JA	156	static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int nbufs,
35c8711c JA	157	unsigned issue_flags)
3b77495a	158	{
8435c6f3	159	unsigned int ret;
3b77495a	160
8435c6f3	161	if (!(req->flags & (REQ_F_BUFFER_RING \| REQ_F_BUFFER_SELECTED)))
3b77495a	162	return 0;
8435c6f3 JA	163
	164	ret = IORING_CQE_F_BUFFER \| (req->buf_index << IORING_CQE_BUFFER_SHIFT);
	165	if (req->flags & REQ_F_BUFFER_RING)
35c8711c	166	__io_put_kbuf_ring(req, nbufs);
8435c6f3 JA	167	else
	168	__io_put_kbuf(req, issue_flags);
	169	return ret;
3b77495a	170	}
35c8711c JA	171
	172	static inline unsigned int io_put_kbuf(struct io_kiocb *req,
	173	unsigned issue_flags)
	174	{
	175	return __io_put_kbufs(req, 1, issue_flags);
	176	}
	177
	178	static inline unsigned int io_put_kbufs(struct io_kiocb *req, int nbufs,
	179	unsigned issue_flags)
	180	{
	181	return __io_put_kbufs(req, nbufs, issue_flags);
	182	}
3b77495a	183	#endif