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 /* 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 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 unsigned int __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_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid); 65 66 static 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 95 static 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 } 101 102 static 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 } 110 111 static 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 } 130 131 static 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 } 139 140 static 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 149