// SPDX-License-Identifier: GPL-2.0#ifndef IOU_KBUF_H#define IOU_KBUF_H #include <uapi/linux/io_uring.h> enum {	/* ring mapped provided buffers */	IOBL_BUF_RING	= 1,	/* ring mapped provided buffers, but mmap'ed by application */	IOBL_MMAP	= 2,	/* buffers are consumed incrementally rather than always fully */	IOBL_INC	= 4, }; 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; 	__u16 flags; 	atomic_t refs;}; 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;	unsigned short nr_iovs;	unsigned short 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, int len, 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;} /* Mapped buffer ring, return io_uring_buf from head */#define io_ring_head_to_buf(br, head, mask)	&(br)->bufs[(head) & (mask)] static inline bool io_kbuf_commit(struct io_kiocb *req,				  struct io_buffer_list *bl, int len, int nr){	if (unlikely(!(req->flags & REQ_F_BUFFERS_COMMIT)))		return true; 	req->flags &= ~REQ_F_BUFFERS_COMMIT; 	if (unlikely(len < 0))		return true; 	if (bl->flags & IOBL_INC) {		struct io_uring_buf *buf; 		buf = io_ring_head_to_buf(bl->buf_ring, bl->head, bl->mask);		if (WARN_ON_ONCE(len > buf->len))			len = buf->len;		buf->len -= len;		if (buf->len) {			buf->addr += len;			return false;		}	} 	bl->head += nr;	return true;} static inline bool __io_put_kbuf_ring(struct io_kiocb *req, int len, int nr){	struct io_buffer_list *bl = req->buf_list;	bool ret = true; 	if (bl) {		ret = io_kbuf_commit(req, bl, len, nr);		req->buf_index = bl->bgid;	}	req->flags &= ~REQ_F_BUFFER_RING;	return ret;} static inline void __io_put_kbuf_list(struct io_kiocb *req, int len,				      struct list_head *list){	if (req->flags & REQ_F_BUFFER_RING) {		__io_put_kbuf_ring(req, len, 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; 	/* len == 0 is fine here, non-ring will always drop all of it */	__io_put_kbuf_list(req, 0, &req->ctx->io_buffers_comp);} static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int len,					  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) {		if (!__io_put_kbuf_ring(req, len, nbufs))			ret |= IORING_CQE_F_BUF_MORE;	} else {		__io_put_kbuf(req, len, issue_flags);	}	return ret;} static inline unsigned int io_put_kbuf(struct io_kiocb *req, int len,				       unsigned issue_flags){	return __io_put_kbufs(req, len, 1, issue_flags);} static inline unsigned int io_put_kbufs(struct io_kiocb *req, int len,					int nbufs, unsigned issue_flags){	return __io_put_kbufs(req, len, nbufs, issue_flags);}#endif