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 }; 19 __u16 bgid; 20 21 /* below is for ring provided buffers */ 22 __u16 buf_nr_pages; 23 __u16 nr_entries; 24 __u16 head; 25 __u16 mask; 26 27 /* ring mapped provided buffers */ 28 __u8 is_mapped; 29 }; 30 31 struct io_buffer { 32 struct list_head list; 33 __u64 addr; 34 __u32 len; 35 __u16 bid; 36 __u16 bgid; 37 }; 38 39 void __user *io_buffer_select(struct io_kiocb *req, size_t *len, 40 unsigned int issue_flags); 41 void io_destroy_buffers(struct io_ring_ctx *ctx); 42 43 int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 44 int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags); 45 46 int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 47 int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags); 48 49 int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 50 int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 51 52 unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); 53 54 void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); 55 56 static inline void io_kbuf_recycle_ring(struct io_kiocb *req) 57 { 58 /* 59 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear 60 * the flag and hence ensure that bl->head doesn't get incremented. 61 * If the tail has already been incremented, hang on to it. 62 * The exception is partial io, that case we should increment bl->head 63 * to monopolize the buffer. 64 */ 65 if (req->buf_list) { 66 if (req->flags & REQ_F_PARTIAL_IO) { 67 /* 68 * If we end up here, then the io_uring_lock has 69 * been kept held since we retrieved the buffer. 70 * For the io-wq case, we already cleared 71 * req->buf_list when the buffer was retrieved, 72 * hence it cannot be set here for that case. 73 */ 74 req->buf_list->head++; 75 req->buf_list = NULL; 76 } else { 77 req->buf_index = req->buf_list->bgid; 78 req->flags &= ~REQ_F_BUFFER_RING; 79 } 80 } 81 } 82 83 static inline bool io_do_buffer_select(struct io_kiocb *req) 84 { 85 if (!(req->flags & REQ_F_BUFFER_SELECT)) 86 return false; 87 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); 88 } 89 90 static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) 91 { 92 if (req->flags & REQ_F_BUFFER_SELECTED) 93 io_kbuf_recycle_legacy(req, issue_flags); 94 if (req->flags & REQ_F_BUFFER_RING) 95 io_kbuf_recycle_ring(req); 96 } 97 98 static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req, 99 struct list_head *list) 100 { 101 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); 102 103 if (req->flags & REQ_F_BUFFER_RING) { 104 if (req->buf_list) { 105 req->buf_index = req->buf_list->bgid; 106 req->buf_list->head++; 107 } 108 req->flags &= ~REQ_F_BUFFER_RING; 109 } else { 110 req->buf_index = req->kbuf->bgid; 111 list_add(&req->kbuf->list, list); 112 req->flags &= ~REQ_F_BUFFER_SELECTED; 113 } 114 115 return ret; 116 } 117 118 static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) 119 { 120 lockdep_assert_held(&req->ctx->completion_lock); 121 122 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 123 return 0; 124 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp); 125 } 126 127 static inline unsigned int io_put_kbuf(struct io_kiocb *req, 128 unsigned issue_flags) 129 { 130 131 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 132 return 0; 133 return __io_put_kbuf(req, issue_flags); 134 } 135 #endif 136