// 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