1 // SPDX-License-Identifier: GPL-2.0
5 #include <uapi/linux/io_uring.h>
7 struct io_buffer_list {
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.
13 struct list_head buf_list;
15 struct page **buf_pages;
16 struct io_uring_buf_ring *buf_ring;
21 /* below is for ring provided buffers */
27 /* ring mapped provided buffers */
32 struct list_head list;
39 void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
40 unsigned int issue_flags);
41 void io_destroy_buffers(struct io_ring_ctx *ctx);
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);
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);
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);
52 unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
54 void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
56 static inline void io_kbuf_recycle_ring(struct io_kiocb *req)
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.
66 if (req->flags & REQ_F_PARTIAL_IO) {
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.
74 req->buf_list->head++;
77 req->buf_index = req->buf_list->bgid;
78 req->flags &= ~REQ_F_BUFFER_RING;
83 static inline bool io_do_buffer_select(struct io_kiocb *req)
85 if (!(req->flags & REQ_F_BUFFER_SELECT))
87 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
90 static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
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);
98 static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
99 struct list_head *list)
101 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
103 if (req->flags & REQ_F_BUFFER_RING) {
105 req->buf_index = req->buf_list->bgid;
106 req->buf_list->head++;
108 req->flags &= ~REQ_F_BUFFER_RING;
110 req->buf_index = req->kbuf->bgid;
111 list_add(&req->kbuf->list, list);
112 req->flags &= ~REQ_F_BUFFER_SELECTED;
118 static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
120 lockdep_assert_held(&req->ctx->completion_lock);
122 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
124 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
127 static inline unsigned int io_put_kbuf(struct io_kiocb *req,
128 unsigned issue_flags)
131 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
133 return __io_put_kbuf(req, issue_flags);