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 | struct rcu_head rcu; |
19 | }; |
20 | __u16 bgid; |
21 | |
22 | /* below is for ring provided buffers */ |
23 | __u16 buf_nr_pages; |
24 | __u16 nr_entries; |
25 | __u16 head; |
26 | __u16 mask; |
27 | |
28 | atomic_t refs; |
29 | |
30 | /* ring mapped provided buffers */ |
31 | __u8 is_buf_ring; |
32 | /* ring mapped provided buffers, but mmap'ed by application */ |
33 | __u8 is_mmap; |
34 | }; |
35 | |
36 | struct io_buffer { |
37 | struct list_head list; |
38 | __u64 addr; |
39 | __u32 len; |
40 | __u16 bid; |
41 | __u16 bgid; |
42 | }; |
43 | |
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); |
47 | |
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); |
50 | |
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); |
53 | |
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); |
56 | int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg); |
57 | |
58 | void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx); |
59 | |
60 | void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); |
61 | |
62 | bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); |
63 | |
64 | void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl); |
65 | struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx, |
66 | unsigned long bgid); |
67 | |
68 | static inline bool io_kbuf_recycle_ring(struct io_kiocb *req) |
69 | { |
70 | /* |
71 | * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear |
72 | * the flag and hence ensure that bl->head doesn't get incremented. |
73 | * If the tail has already been incremented, hang on to it. |
74 | * The exception is partial io, that case we should increment bl->head |
75 | * to monopolize the buffer. |
76 | */ |
77 | if (req->buf_list) { |
78 | req->buf_index = req->buf_list->bgid; |
79 | req->flags &= ~REQ_F_BUFFER_RING; |
80 | return true; |
81 | } |
82 | return false; |
83 | } |
84 | |
85 | static inline bool io_do_buffer_select(struct io_kiocb *req) |
86 | { |
87 | if (!(req->flags & REQ_F_BUFFER_SELECT)) |
88 | return false; |
89 | return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); |
90 | } |
91 | |
92 | static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) |
93 | { |
94 | if (req->flags & REQ_F_BL_NO_RECYCLE) |
95 | return false; |
96 | if (req->flags & REQ_F_BUFFER_SELECTED) |
97 | return io_kbuf_recycle_legacy(req, issue_flags); |
98 | if (req->flags & REQ_F_BUFFER_RING) |
99 | return io_kbuf_recycle_ring(req); |
100 | return false; |
101 | } |
102 | |
103 | static inline void __io_put_kbuf_ring(struct io_kiocb *req) |
104 | { |
105 | if (req->buf_list) { |
106 | req->buf_index = req->buf_list->bgid; |
107 | req->buf_list->head++; |
108 | } |
109 | req->flags &= ~REQ_F_BUFFER_RING; |
110 | } |
111 | |
112 | static inline void __io_put_kbuf_list(struct io_kiocb *req, |
113 | struct list_head *list) |
114 | { |
115 | if (req->flags & REQ_F_BUFFER_RING) { |
116 | __io_put_kbuf_ring(req); |
117 | } else { |
118 | req->buf_index = req->kbuf->bgid; |
119 | list_add(new: &req->kbuf->list, head: list); |
120 | req->flags &= ~REQ_F_BUFFER_SELECTED; |
121 | } |
122 | } |
123 | |
124 | static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) |
125 | { |
126 | unsigned int ret; |
127 | |
128 | lockdep_assert_held(&req->ctx->completion_lock); |
129 | |
130 | if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) |
131 | return 0; |
132 | |
133 | ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); |
134 | __io_put_kbuf_list(req, list: &req->ctx->io_buffers_comp); |
135 | return ret; |
136 | } |
137 | |
138 | static inline unsigned int io_put_kbuf(struct io_kiocb *req, |
139 | unsigned issue_flags) |
140 | { |
141 | unsigned int ret; |
142 | |
143 | if (!(req->flags & (REQ_F_BUFFER_RING | REQ_F_BUFFER_SELECTED))) |
144 | return 0; |
145 | |
146 | ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); |
147 | if (req->flags & REQ_F_BUFFER_RING) |
148 | __io_put_kbuf_ring(req); |
149 | else |
150 | __io_put_kbuf(req, issue_flags); |
151 | return ret; |
152 | } |
153 | #endif |
154 | |