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;
22 /* below is for ring provided buffers */
28 /* ring mapped provided buffers */
30 /* ring mapped provided buffers, but mmap'ed by application */
32 /* bl is visible from an RCU point of view for lookup */
37 struct list_head list;
44 void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
45 unsigned int issue_flags);
46 void io_destroy_buffers(struct io_ring_ctx *ctx);
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);
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);
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);
57 void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);
59 unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
61 bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
63 void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid);
65 static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
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.
75 if (req->flags & REQ_F_PARTIAL_IO) {
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.
83 req->buf_list->head++;
86 req->buf_index = req->buf_list->bgid;
87 req->flags &= ~REQ_F_BUFFER_RING;
94 static inline bool io_do_buffer_select(struct io_kiocb *req)
96 if (!(req->flags & REQ_F_BUFFER_SELECT))
98 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
101 static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
103 if (req->flags & REQ_F_BUFFER_SELECTED)
104 return io_kbuf_recycle_legacy(req, issue_flags);
105 if (req->flags & REQ_F_BUFFER_RING)
106 return io_kbuf_recycle_ring(req);
110 static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
111 struct list_head *list)
113 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
115 if (req->flags & REQ_F_BUFFER_RING) {
117 req->buf_index = req->buf_list->bgid;
118 req->buf_list->head++;
120 req->flags &= ~REQ_F_BUFFER_RING;
122 req->buf_index = req->kbuf->bgid;
123 list_add(&req->kbuf->list, list);
124 req->flags &= ~REQ_F_BUFFER_SELECTED;
130 static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
132 lockdep_assert_held(&req->ctx->completion_lock);
134 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
136 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
139 static inline unsigned int io_put_kbuf(struct io_kiocb *req,
140 unsigned issue_flags)
143 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
145 return __io_put_kbuf(req, issue_flags);