1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #ifndef IOU_KBUF_H |
3 | #define IOU_KBUF_H |
4 | |
5 | #include <uapi/linux/io_uring.h> |
6 | |
7 | struct io_buffer_list { |
8 | /* |
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. |
11 | */ |
12 | union { |
13 | struct list_head buf_list; |
14 | struct { |
15 | struct page **buf_pages; |
16 | struct io_uring_buf_ring *buf_ring; |
17 | }; |
18 | }; |
19 | __u16 bgid; |
20 | |
21 | /* below is for ring provided buffers */ |
22 | __u16 buf_nr_pages; |
23 | __u16 nr_entries; |
24 | __u16 head; |
25 | __u16 mask; |
26 | |
27 | /* ring mapped provided buffers */ |
28 | __u8 is_mapped; |
29 | /* ring mapped provided buffers, but mmap'ed by application */ |
30 | __u8 is_mmap; |
31 | }; |
32 | |
33 | struct io_buffer { |
34 | struct list_head list; |
35 | __u64 addr; |
36 | __u32 len; |
37 | __u16 bid; |
38 | __u16 bgid; |
39 | }; |
40 | |
41 | void __user *io_buffer_select(struct io_kiocb *req, size_t *len, |
42 | unsigned int issue_flags); |
43 | void io_destroy_buffers(struct io_ring_ctx *ctx); |
44 | |
45 | int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); |
46 | int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags); |
47 | |
48 | int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); |
49 | int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags); |
50 | |
51 | int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); |
52 | int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); |
53 | |
54 | unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); |
55 | |
56 | void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); |
57 | |
58 | void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid); |
59 | |
60 | static inline void io_kbuf_recycle_ring(struct io_kiocb *req) |
61 | { |
62 | /* |
63 | * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear |
64 | * the flag and hence ensure that bl->head doesn't get incremented. |
65 | * If the tail has already been incremented, hang on to it. |
66 | * The exception is partial io, that case we should increment bl->head |
67 | * to monopolize the buffer. |
68 | */ |
69 | if (req->buf_list) { |
70 | if (req->flags & REQ_F_PARTIAL_IO) { |
71 | /* |
72 | * If we end up here, then the io_uring_lock has |
73 | * been kept held since we retrieved the buffer. |
74 | * For the io-wq case, we already cleared |
75 | * req->buf_list when the buffer was retrieved, |
76 | * hence it cannot be set here for that case. |
77 | */ |
78 | req->buf_list->head++; |
79 | req->buf_list = NULL; |
80 | } else { |
81 | req->buf_index = req->buf_list->bgid; |
82 | req->flags &= ~REQ_F_BUFFER_RING; |
83 | } |
84 | } |
85 | } |
86 | |
87 | static inline bool io_do_buffer_select(struct io_kiocb *req) |
88 | { |
89 | if (!(req->flags & REQ_F_BUFFER_SELECT)) |
90 | return false; |
91 | return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); |
92 | } |
93 | |
94 | static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) |
95 | { |
96 | if (req->flags & REQ_F_BUFFER_SELECTED) |
97 | io_kbuf_recycle_legacy(req, issue_flags); |
98 | if (req->flags & REQ_F_BUFFER_RING) |
99 | io_kbuf_recycle_ring(req); |
100 | } |
101 | |
102 | static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req, |
103 | struct list_head *list) |
104 | { |
105 | unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); |
106 | |
107 | if (req->flags & REQ_F_BUFFER_RING) { |
108 | if (req->buf_list) { |
109 | req->buf_index = req->buf_list->bgid; |
110 | req->buf_list->head++; |
111 | } |
112 | req->flags &= ~REQ_F_BUFFER_RING; |
113 | } else { |
114 | req->buf_index = req->kbuf->bgid; |
115 | list_add(new: &req->kbuf->list, head: list); |
116 | req->flags &= ~REQ_F_BUFFER_SELECTED; |
117 | } |
118 | |
119 | return ret; |
120 | } |
121 | |
122 | static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) |
123 | { |
124 | lockdep_assert_held(&req->ctx->completion_lock); |
125 | |
126 | if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) |
127 | return 0; |
128 | return __io_put_kbuf_list(req, list: &req->ctx->io_buffers_comp); |
129 | } |
130 | |
131 | static inline unsigned int io_put_kbuf(struct io_kiocb *req, |
132 | unsigned issue_flags) |
133 | { |
134 | |
135 | if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) |
136 | return 0; |
137 | return __io_put_kbuf(req, issue_flags); |
138 | } |
139 | #endif |
140 | |