// 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; /* 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; }; 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); void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid); 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