[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;

	/* ring mapped provided buffers */
	__u8 is_mapped;
};

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)
{
	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)
{
	unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);

	if (req->flags & REQ_F_BUFFER_RING) {
		if (req->buf_list) {
			req->buf_index = req->buf_list->bgid;
			req->buf_list->head++;
		}
		req->flags &= ~REQ_F_BUFFER_RING;
	} else {
		req->buf_index = req->kbuf->bgid;
		list_add(&req->kbuf->list, list);
		req->flags &= ~REQ_F_BUFFER_SELECTED;
	}

	return ret;
}

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;
25a2c188 JA	26
	27	/* ring mapped provided buffers */
	28	__u8 is_mapped;
3b77495a JA	29	};
	30
	31	struct io_buffer {
	32	struct list_head list;
	33	__u64 addr;
	34	__u32 len;
	35	__u16 bid;
	36	__u16 bgid;
	37	};
	38
	39	void __user io_buffer_select(struct io_kiocb req, size_t *len,
	40	unsigned int issue_flags);
3b77495a JA	41	void io_destroy_buffers(struct io_ring_ctx *ctx);
	42
	43	int io_remove_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	44	int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
	45
	46	int io_provide_buffers_prep(struct io_kiocb req, const struct io_uring_sqe sqe);
	47	int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
	48
	49	int io_register_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
	50	int io_unregister_pbuf_ring(struct io_ring_ctx ctx, void __user arg);
	51
53ccf69b PB	52	unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
53ccf69b PB	53
024b8fde	54	void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
795bbbc8 HX	55
	56	static inline void io_kbuf_recycle_ring(struct io_kiocb *req)
	57	{
	58	/*
	59	* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
	60	* the flag and hence ensure that bl->head doesn't get incremented.
	61	* If the tail has already been incremented, hang on to it.
	62	* The exception is partial io, that case we should increment bl->head
	63	* to monopolize the buffer.
	64	*/
	65	if (req->buf_list) {
	66	if (req->flags & REQ_F_PARTIAL_IO) {
	67	/*
	68	* If we end up here, then the io_uring_lock has
	69	* been kept held since we retrieved the buffer.
	70	* For the io-wq case, we already cleared
	71	* req->buf_list when the buffer was retrieved,
	72	* hence it cannot be set here for that case.
	73	*/
	74	req->buf_list->head++;
	75	req->buf_list = NULL;
	76	} else {
	77	req->buf_index = req->buf_list->bgid;
	78	req->flags &= ~REQ_F_BUFFER_RING;
	79	}
	80	}
	81	}
024b8fde	82
3b77495a JA	83	static inline bool io_do_buffer_select(struct io_kiocb *req)
	84	{
	85	if (!(req->flags & REQ_F_BUFFER_SELECT))
	86	return false;
	87	return !(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING));
	88	}
	89
	90	static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
	91	{
024b8fde HX	92	if (req->flags & REQ_F_BUFFER_SELECTED)
	93	io_kbuf_recycle_legacy(req, issue_flags);
	94	if (req->flags & REQ_F_BUFFER_RING)
	95	io_kbuf_recycle_ring(req);
3b77495a JA	96	}
3b77495a JA	97
53ccf69b PB	98	static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
53ccf69b PB	99	struct list_head *list)
3b77495a	100	{
32f3c434 DY	101	unsigned int ret = IORING_CQE_F_BUFFER \| (req->buf_index << IORING_CQE_BUFFER_SHIFT);
32f3c434 DY	102
3b77495a	103	if (req->flags & REQ_F_BUFFER_RING) {
32f3c434 DY	104	if (req->buf_list) {
32f3c434 DY	105	req->buf_index = req->buf_list->bgid;
3b77495a	106	req->buf_list->head++;
32f3c434	107	}
3b77495a JA	108	req->flags &= ~REQ_F_BUFFER_RING;
3b77495a JA	109	} else {
32f3c434	110	req->buf_index = req->kbuf->bgid;
3b77495a JA	111	list_add(&req->kbuf->list, list);
	112	req->flags &= ~REQ_F_BUFFER_SELECTED;
	113	}
	114
32f3c434	115	return ret;
3b77495a JA	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