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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
7enum {
8 /* ring mapped provided buffers */
9 IOBL_BUF_RING = 1,
10 /* ring mapped provided buffers, but mmap'ed by application */
11 IOBL_MMAP = 2,
12 /* buffers are consumed incrementally rather than always fully */
13 IOBL_INC = 4,
14
15};
16
17struct io_buffer_list {
18 /*
19 * If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
20 * then these are classic provided buffers and ->buf_list is used.
21 */
22 union {
23 struct list_head buf_list;
24 struct {
25 struct page **buf_pages;
26 struct io_uring_buf_ring *buf_ring;
27 };
28 struct rcu_head rcu;
29 };
30 __u16 bgid;
31
32 /* below is for ring provided buffers */
33 __u16 buf_nr_pages;
34 __u16 nr_entries;
35 __u16 head;
36 __u16 mask;
37
38 __u16 flags;
39
40 atomic_t refs;
41};
42
43struct io_buffer {
44 struct list_head list;
45 __u64 addr;
46 __u32 len;
47 __u16 bid;
48 __u16 bgid;
49};
50
51enum {
52 /* can alloc a bigger vec */
53 KBUF_MODE_EXPAND = 1,
54 /* if bigger vec allocated, free old one */
55 KBUF_MODE_FREE = 2,
56};
57
58struct buf_sel_arg {
59 struct iovec *iovs;
60 size_t out_len;
61 size_t max_len;
62 unsigned short nr_iovs;
63 unsigned short mode;
64};
65
66void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
67 unsigned int issue_flags);
68int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg,
69 unsigned int issue_flags);
70int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg);
71void io_destroy_buffers(struct io_ring_ctx *ctx);
72
73int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
74int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
75
76int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
77int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
78
79int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
80int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
81int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg);
82
83void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags);
84
85bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
86
87void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl);
88struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
89 unsigned long bgid);
90int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma);
91
92static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
93{
94 /*
95 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
96 * the flag and hence ensure that bl->head doesn't get incremented.
97 * If the tail has already been incremented, hang on to it.
98 * The exception is partial io, that case we should increment bl->head
99 * to monopolize the buffer.
100 */
101 if (req->buf_list) {
102 req->buf_index = req->buf_list->bgid;
103 req->flags &= ~(REQ_F_BUFFER_RING|REQ_F_BUFFERS_COMMIT);
104 return true;
105 }
106 return false;
107}
108
109static inline bool io_do_buffer_select(struct io_kiocb *req)
110{
111 if (!(req->flags & REQ_F_BUFFER_SELECT))
112 return false;
113 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
114}
115
116static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
117{
118 if (req->flags & REQ_F_BL_NO_RECYCLE)
119 return false;
120 if (req->flags & REQ_F_BUFFER_SELECTED)
121 return io_kbuf_recycle_legacy(req, issue_flags);
122 if (req->flags & REQ_F_BUFFER_RING)
123 return io_kbuf_recycle_ring(req);
124 return false;
125}
126
127/* Mapped buffer ring, return io_uring_buf from head */
128#define io_ring_head_to_buf(br, head, mask) &(br)->bufs[(head) & (mask)]
129
130static inline bool io_kbuf_commit(struct io_kiocb *req,
131 struct io_buffer_list *bl, int len, int nr)
132{
133 if (unlikely(!(req->flags & REQ_F_BUFFERS_COMMIT)))
134 return true;
135
136 req->flags &= ~REQ_F_BUFFERS_COMMIT;
137
138 if (unlikely(len < 0))
139 return true;
140
141 if (bl->flags & IOBL_INC) {
142 struct io_uring_buf *buf;
143
144 buf = io_ring_head_to_buf(bl->buf_ring, bl->head, bl->mask);
145 if (WARN_ON_ONCE(len > buf->len))
146 len = buf->len;
147 buf->len -= len;
148 if (buf->len) {
149 buf->addr += len;
150 return false;
151 }
152 }
153
154 bl->head += nr;
155 return true;
156}
157
158static inline bool __io_put_kbuf_ring(struct io_kiocb *req, int len, int nr)
159{
160 struct io_buffer_list *bl = req->buf_list;
161 bool ret = true;
162
163 if (bl) {
164 ret = io_kbuf_commit(req, bl, len, nr);
165 req->buf_index = bl->bgid;
166 }
167 req->flags &= ~REQ_F_BUFFER_RING;
168 return ret;
169}
170
171static inline void __io_put_kbuf_list(struct io_kiocb *req, int len,
172 struct list_head *list)
173{
174 if (req->flags & REQ_F_BUFFER_RING) {
175 __io_put_kbuf_ring(req, len, 1);
176 } else {
177 req->buf_index = req->kbuf->bgid;
178 list_add(&req->kbuf->list, list);
179 req->flags &= ~REQ_F_BUFFER_SELECTED;
180 }
181}
182
183static inline void io_kbuf_drop(struct io_kiocb *req)
184{
185 lockdep_assert_held(&req->ctx->completion_lock);
186
187 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
188 return;
189
190 /* len == 0 is fine here, non-ring will always drop all of it */
191 __io_put_kbuf_list(req, 0, &req->ctx->io_buffers_comp);
192}
193
194static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int len,
195 int nbufs, unsigned issue_flags)
196{
197 unsigned int ret;
198
199 if (!(req->flags & (REQ_F_BUFFER_RING | REQ_F_BUFFER_SELECTED)))
200 return 0;
201
202 ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
203 if (req->flags & REQ_F_BUFFER_RING) {
204 if (!__io_put_kbuf_ring(req, len, nbufs))
205 ret |= IORING_CQE_F_BUF_MORE;
206 } else {
207 __io_put_kbuf(req, len, issue_flags);
208 }
209 return ret;
210}
211
212static inline unsigned int io_put_kbuf(struct io_kiocb *req, int len,
213 unsigned issue_flags)
214{
215 return __io_put_kbufs(req, len, 1, issue_flags);
216}
217
218static inline unsigned int io_put_kbufs(struct io_kiocb *req, int len,
219 int nbufs, unsigned issue_flags)
220{
221 return __io_put_kbufs(req, len, nbufs, issue_flags);
222}
223#endif
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
7struct 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 /* ring mapped provided buffers */
29 __u8 is_mapped;
30 /* ring mapped provided buffers, but mmap'ed by application */
31 __u8 is_mmap;
32 /* bl is visible from an RCU point of view for lookup */
33 __u8 is_ready;
34};
35
36struct io_buffer {
37 struct list_head list;
38 __u64 addr;
39 __u32 len;
40 __u16 bid;
41 __u16 bgid;
42};
43
44void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
45 unsigned int issue_flags);
46void io_destroy_buffers(struct io_ring_ctx *ctx);
47
48int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
49int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
50
51int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
52int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
53
54int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
55int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
56int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg);
57
58void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);
59
60unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
61
62bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
63
64void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid);
65
66static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
67{
68 /*
69 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
70 * the flag and hence ensure that bl->head doesn't get incremented.
71 * If the tail has already been incremented, hang on to it.
72 * The exception is partial io, that case we should increment bl->head
73 * to monopolize the buffer.
74 */
75 if (req->buf_list) {
76 if (req->flags & REQ_F_PARTIAL_IO) {
77 /*
78 * If we end up here, then the io_uring_lock has
79 * been kept held since we retrieved the buffer.
80 * For the io-wq case, we already cleared
81 * req->buf_list when the buffer was retrieved,
82 * hence it cannot be set here for that case.
83 */
84 req->buf_list->head++;
85 req->buf_list = NULL;
86 } else {
87 req->buf_index = req->buf_list->bgid;
88 req->flags &= ~REQ_F_BUFFER_RING;
89 return true;
90 }
91 }
92 return false;
93}
94
95static inline bool io_do_buffer_select(struct io_kiocb *req)
96{
97 if (!(req->flags & REQ_F_BUFFER_SELECT))
98 return false;
99 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
100}
101
102static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
103{
104 if (req->flags & REQ_F_BUFFER_SELECTED)
105 return io_kbuf_recycle_legacy(req, issue_flags);
106 if (req->flags & REQ_F_BUFFER_RING)
107 return io_kbuf_recycle_ring(req);
108 return false;
109}
110
111static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
112 struct list_head *list)
113{
114 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
115
116 if (req->flags & REQ_F_BUFFER_RING) {
117 if (req->buf_list) {
118 req->buf_index = req->buf_list->bgid;
119 req->buf_list->head++;
120 }
121 req->flags &= ~REQ_F_BUFFER_RING;
122 } else {
123 req->buf_index = req->kbuf->bgid;
124 list_add(&req->kbuf->list, list);
125 req->flags &= ~REQ_F_BUFFER_SELECTED;
126 }
127
128 return ret;
129}
130
131static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
132{
133 lockdep_assert_held(&req->ctx->completion_lock);
134
135 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
136 return 0;
137 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
138}
139
140static inline unsigned int io_put_kbuf(struct io_kiocb *req,
141 unsigned issue_flags)
142{
143
144 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
145 return 0;
146 return __io_put_kbuf(req, issue_flags);
147}
148#endif