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 enum { 45 /* can alloc a bigger vec */ 46 KBUF_MODE_EXPAND = 1, 47 /* if bigger vec allocated, free old one */ 48 KBUF_MODE_FREE = 2, 49 }; 50 51 struct buf_sel_arg { 52 struct iovec *iovs; 53 size_t out_len; 54 size_t max_len; 55 int nr_iovs; 56 int mode; 57 }; 58 59 void __user *io_buffer_select(struct io_kiocb *req, size_t *len, 60 unsigned int issue_flags); 61 int io_buffers_select(struct io_kiocb *req, struct buf_sel_arg *arg, 62 unsigned int issue_flags); 63 int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg); 64 void io_destroy_buffers(struct io_ring_ctx *ctx); 65 66 int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 67 int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags); 68 69 int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 70 int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags); 71 72 int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 73 int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 74 int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg); 75 76 void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); 77 78 bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); 79 80 void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl); 81 struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx, 82 unsigned long bgid); 83 int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma); 84 85 static inline bool io_kbuf_recycle_ring(struct io_kiocb *req) 86 { 87 /* 88 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear 89 * the flag and hence ensure that bl->head doesn't get incremented. 90 * If the tail has already been incremented, hang on to it. 91 * The exception is partial io, that case we should increment bl->head 92 * to monopolize the buffer. 93 */ 94 if (req->buf_list) { 95 req->buf_index = req->buf_list->bgid; 96 req->flags &= ~(REQ_F_BUFFER_RING|REQ_F_BUFFERS_COMMIT); 97 return true; 98 } 99 return false; 100 } 101 102 static inline bool io_do_buffer_select(struct io_kiocb *req) 103 { 104 if (!(req->flags & REQ_F_BUFFER_SELECT)) 105 return false; 106 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); 107 } 108 109 static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) 110 { 111 if (req->flags & REQ_F_BL_NO_RECYCLE) 112 return false; 113 if (req->flags & REQ_F_BUFFER_SELECTED) 114 return io_kbuf_recycle_legacy(req, issue_flags); 115 if (req->flags & REQ_F_BUFFER_RING) 116 return io_kbuf_recycle_ring(req); 117 return false; 118 } 119 120 static inline void __io_put_kbuf_ring(struct io_kiocb *req, int nr) 121 { 122 struct io_buffer_list *bl = req->buf_list; 123 124 if (bl) { 125 if (req->flags & REQ_F_BUFFERS_COMMIT) { 126 bl->head += nr; 127 req->flags &= ~REQ_F_BUFFERS_COMMIT; 128 } 129 req->buf_index = bl->bgid; 130 } 131 req->flags &= ~REQ_F_BUFFER_RING; 132 } 133 134 static inline void __io_put_kbuf_list(struct io_kiocb *req, 135 struct list_head *list) 136 { 137 if (req->flags & REQ_F_BUFFER_RING) { 138 __io_put_kbuf_ring(req, 1); 139 } else { 140 req->buf_index = req->kbuf->bgid; 141 list_add(&req->kbuf->list, list); 142 req->flags &= ~REQ_F_BUFFER_SELECTED; 143 } 144 } 145 146 static inline void io_kbuf_drop(struct io_kiocb *req) 147 { 148 lockdep_assert_held(&req->ctx->completion_lock); 149 150 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 151 return; 152 153 __io_put_kbuf_list(req, &req->ctx->io_buffers_comp); 154 } 155 156 static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int nbufs, 157 unsigned issue_flags) 158 { 159 unsigned int ret; 160 161 if (!(req->flags & (REQ_F_BUFFER_RING | REQ_F_BUFFER_SELECTED))) 162 return 0; 163 164 ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); 165 if (req->flags & REQ_F_BUFFER_RING) 166 __io_put_kbuf_ring(req, nbufs); 167 else 168 __io_put_kbuf(req, issue_flags); 169 return ret; 170 } 171 172 static inline unsigned int io_put_kbuf(struct io_kiocb *req, 173 unsigned issue_flags) 174 { 175 return __io_put_kbufs(req, 1, issue_flags); 176 } 177 178 static inline unsigned int io_put_kbufs(struct io_kiocb *req, int nbufs, 179 unsigned issue_flags) 180 { 181 return __io_put_kbufs(req, nbufs, issue_flags); 182 } 183 #endif 184