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 enum { 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 17 struct 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 43 struct io_buffer { 44 struct list_head list; 45 __u64 addr; 46 __u32 len; 47 __u16 bid; 48 __u16 bgid; 49 }; 50 51 enum { 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 58 struct 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 66 void __user *io_buffer_select(struct io_kiocb *req, size_t *len, 67 unsigned int issue_flags); 68 int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg, 69 unsigned int issue_flags); 70 int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg); 71 void io_destroy_buffers(struct io_ring_ctx *ctx); 72 73 int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 74 int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags); 75 76 int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 77 int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags); 78 79 int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 80 int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 81 int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg); 82 83 void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags); 84 85 bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); 86 87 void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl); 88 struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx, 89 unsigned long bgid); 90 int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma); 91 92 static 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 } 108 109 static 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 } 115 116 static 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)] 129 130 static 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 } 157 158 static 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 } 170 171 static 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 } 182 183 static 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 } 193 194 static 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 } 211 212 static 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 } 217 218 static 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 224