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(&req->kbuf->list, 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, &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