[thirdparty/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;

	/* ring mapped provided buffers */
	__u8 is_mapped;
	/* ring mapped provided buffers, but mmap'ed by application */
	__u8 is_mmap;
	/* bl is visible from an RCU point of view for lookup */
	__u8 is_ready;
};

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);

void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);

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

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

void *io_pbuf_get_address(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) {
		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;
			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_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 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	};
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 JA	27
	28	/* ring mapped provided buffers */
	29	__u8 is_mapped;
c56e022c JA	30	/* ring mapped provided buffers, but mmap'ed by application */
c56e022c JA	31	__u8 is_mmap;
5cf4f52e JA	32	/* bl is visible from an RCU point of view for lookup */
5cf4f52e JA	33	__u8 is_ready;
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);
	56
c392cbec JA	57	void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);
c392cbec JA	58
53ccf69b PB	59	unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
53ccf69b PB	60
89d528ba	61	bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
795bbbc8	62
c56e022c JA	63	void io_pbuf_get_address(struct io_ring_ctx ctx, unsigned long bgid);
c56e022c JA	64
89d528ba	65	static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
795bbbc8 HX	66	{
	67	/*
	68	* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
	69	* the flag and hence ensure that bl->head doesn't get incremented.
	70	* If the tail has already been incremented, hang on to it.
	71	* The exception is partial io, that case we should increment bl->head
	72	* to monopolize the buffer.
	73	*/
	74	if (req->buf_list) {
	75	if (req->flags & REQ_F_PARTIAL_IO) {
	76	/*
	77	* If we end up here, then the io_uring_lock has
	78	* been kept held since we retrieved the buffer.
	79	* For the io-wq case, we already cleared
	80	* req->buf_list when the buffer was retrieved,
	81	* hence it cannot be set here for that case.
	82	*/
	83	req->buf_list->head++;
	84	req->buf_list = NULL;
	85	} else {
	86	req->buf_index = req->buf_list->bgid;
	87	req->flags &= ~REQ_F_BUFFER_RING;
89d528ba	88	return true;
795bbbc8 HX	89	}
795bbbc8 HX	90	}
89d528ba	91	return false;
795bbbc8	92	}
024b8fde	93
3b77495a JA	94	static inline bool io_do_buffer_select(struct io_kiocb *req)
	95	{
	96	if (!(req->flags & REQ_F_BUFFER_SELECT))
	97	return false;
	98	return !(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING));
	99	}
	100
89d528ba	101	static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
3b77495a	102	{
024b8fde	103	if (req->flags & REQ_F_BUFFER_SELECTED)
89d528ba	104	return io_kbuf_recycle_legacy(req, issue_flags);
024b8fde	105	if (req->flags & REQ_F_BUFFER_RING)
89d528ba DY	106	return io_kbuf_recycle_ring(req);
89d528ba DY	107	return false;
3b77495a JA	108	}
3b77495a JA	109
53ccf69b PB	110	static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
53ccf69b PB	111	struct list_head *list)
3b77495a	112	{
32f3c434 DY	113	unsigned int ret = IORING_CQE_F_BUFFER \| (req->buf_index << IORING_CQE_BUFFER_SHIFT);
32f3c434 DY	114
3b77495a	115	if (req->flags & REQ_F_BUFFER_RING) {
32f3c434 DY	116	if (req->buf_list) {
32f3c434 DY	117	req->buf_index = req->buf_list->bgid;
3b77495a	118	req->buf_list->head++;
32f3c434	119	}
3b77495a JA	120	req->flags &= ~REQ_F_BUFFER_RING;
3b77495a JA	121	} else {
32f3c434	122	req->buf_index = req->kbuf->bgid;
3b77495a JA	123	list_add(&req->kbuf->list, list);
	124	req->flags &= ~REQ_F_BUFFER_SELECTED;
	125	}
	126
32f3c434	127	return ret;
3b77495a JA	128	}
	129
	130	static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
	131	{
	132	lockdep_assert_held(&req->ctx->completion_lock);
	133
	134	if (!(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING)))
	135	return 0;
53ccf69b	136	return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
3b77495a JA	137	}
	138
	139	static inline unsigned int io_put_kbuf(struct io_kiocb *req,
	140	unsigned issue_flags)
	141	{
3b77495a JA	142
	143	if (!(req->flags & (REQ_F_BUFFER_SELECTED\|REQ_F_BUFFER_RING)))
	144	return 0;
53ccf69b	145	return __io_put_kbuf(req, issue_flags);
3b77495a JA	146	}
3b77495a JA	147	#endif