[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;
		};
	};
	__u16 bgid;

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

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);

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

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

static inline void 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) {
		if (req->flags & REQ_F_PARTIAL_IO) {
			/*
			 * If we end up here, then the io_uring_lock has
			 * been kept held since we retrieved the buffer.
			 * For the io-wq case, we already cleared
			 * req->buf_list when the buffer was retrieved,
			 * hence it cannot be set here for that case.
			 */
			req->buf_list->head++;
			req->buf_list = NULL;
		} else {
			req->buf_index = req->buf_list->bgid;
			req->flags &= ~REQ_F_BUFFER_RING;
		}
	}
}

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 void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
{
	/*
	 * READV uses fields in `struct io_rw` (len/addr) to stash the selected
	 * buffer data. However if that buffer is recycled the original request
	 * data stored in addr is lost. Therefore forbid recycling for now.
	 */
	if (req->opcode == IORING_OP_READV)
		return;

	if (req->flags & REQ_F_BUFFER_SELECTED)
		io_kbuf_recycle_legacy(req, issue_flags);
	if (req->flags & REQ_F_BUFFER_RING)
		io_kbuf_recycle_ring(req);
}

static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
					      struct list_head *list)
{
	if (req->flags & REQ_F_BUFFER_RING) {
		if (req->buf_list)
			req->buf_list->head++;
		req->flags &= ~REQ_F_BUFFER_RING;
	} else {
		list_add(&req->kbuf->list, list);
		req->flags &= ~REQ_F_BUFFER_SELECTED;
	}

	return IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
}

static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
{
	lockdep_assert_held(&req->ctx->completion_lock);

	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
		return 0;
	return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
}

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

	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
		return 0;
	return __io_put_kbuf(req, 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	};
	18	};
	19	__u16 bgid;
	20
	21	/* below is for ring provided buffers */
	22	__u16 buf_nr_pages;
	23	__u16 nr_entries;
	24	__u16 head;
	25	__u16 mask;
	26	};
	27
	28	struct io_buffer {
	29	struct list_head list;
	30	__u64 addr;
	31	__u32 len;
	32	__u16 bid;
	33	__u16 bgid;
	34	};
	35
	36	void __user io_buffer_select(struct io_kiocb req, size_t *len,
	37	unsigned int issue_flags);
3b77495a JA	38	void io_destroy_buffers(struct io_ring_ctx *ctx);
	39
	40	int io_remove_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	41	int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
	42
	43	int io_provide_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	44	int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
	45
	46	int io_register_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
	47	int io_unregister_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
	48
53ccf69b PB	49	unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
53ccf69b PB	50
024b8fde	51	void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
795bbbc8 HX	52
	53	static inline void io_kbuf_recycle_ring(struct io_kiocb *req)
	54	{
	55	/*
	56	* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
	57	* the flag and hence ensure that bl->head doesn't get incremented.
	58	* If the tail has already been incremented, hang on to it.
	59	* The exception is partial io, that case we should increment bl->head
	60	* to monopolize the buffer.
	61	*/
	62	if (req->buf_list) {
	63	if (req->flags & REQ_F_PARTIAL_IO) {
	64	/*
	65	* If we end up here, then the io_uring_lock has
	66	* been kept held since we retrieved the buffer.
	67	* For the io-wq case, we already cleared
	68	* req->buf_list when the buffer was retrieved,
	69	* hence it cannot be set here for that case.
	70	*/
	71	req->buf_list->head++;
	72	req->buf_list = NULL;
	73	} else {
	74	req->buf_index = req->buf_list->bgid;
	75	req->flags &= ~REQ_F_BUFFER_RING;
	76	}
	77	}
	78	}
024b8fde	79
3b77495a JA	80	static inline bool io_do_buffer_select(struct io_kiocb *req)
	81	{
	82	if (!(req->flags & REQ_F_BUFFER_SELECT))
	83	return false;
	84	return !(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING));
	85	}
	86
	87	static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
	88	{
3b77495a JA	89	/*
	90	* READV uses fields in `struct io_rw` (len/addr) to stash the selected
	91	* buffer data. However if that buffer is recycled the original request
	92	* data stored in addr is lost. Therefore forbid recycling for now.
	93	*/
	94	if (req->opcode == IORING_OP_READV)
	95	return;
	96
024b8fde HX	97	if (req->flags & REQ_F_BUFFER_SELECTED)
	98	io_kbuf_recycle_legacy(req, issue_flags);
	99	if (req->flags & REQ_F_BUFFER_RING)
	100	io_kbuf_recycle_ring(req);
3b77495a JA	101	}
3b77495a JA	102
53ccf69b PB	103	static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
53ccf69b PB	104	struct list_head *list)
3b77495a JA	105	{
	106	if (req->flags & REQ_F_BUFFER_RING) {
	107	if (req->buf_list)
	108	req->buf_list->head++;
	109	req->flags &= ~REQ_F_BUFFER_RING;
	110	} else {
	111	list_add(&req->kbuf->list, list);
	112	req->flags &= ~REQ_F_BUFFER_SELECTED;
	113	}
	114
	115	return IORING_CQE_F_BUFFER \| (req->buf_index << IORING_CQE_BUFFER_SHIFT);
	116	}
	117
	118	static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
	119	{
	120	lockdep_assert_held(&req->ctx->completion_lock);
	121
	122	if (!(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING)))
	123	return 0;
53ccf69b	124	return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
3b77495a JA	125	}
	126
	127	static inline unsigned int io_put_kbuf(struct io_kiocb *req,
	128	unsigned issue_flags)
	129	{
3b77495a JA	130
	131	if (!(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING)))
	132	return 0;
53ccf69b	133	return __io_put_kbuf(req, issue_flags);
3b77495a JA	134	}
3b77495a JA	135	#endif