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
io_kbuf_recycle_ring(struct io_kiocb * req)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
io_do_buffer_select(struct io_kiocb * req)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
io_kbuf_recycle(struct io_kiocb * req,unsigned issue_flags)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
__io_put_kbuf_list(struct io_kiocb * req,struct list_head * list)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(&req->kbuf->list, list);
116 req->flags &= ~REQ_F_BUFFER_SELECTED;
117 }
118
119 return ret;
120 }
121
io_put_kbuf_comp(struct io_kiocb * req)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, &req->ctx->io_buffers_comp);
129 }
130
io_put_kbuf(struct io_kiocb * req,unsigned issue_flags)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
