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 /* ring mapped provided buffers, but mmap'ed by application */ 30 __u8 is_mmap; 31 }; 32 33 struct io_buffer { 34 struct list_head list; 35 __u64 addr; 36 __u32 len; 37 __u16 bid; 38 __u16 bgid; 39 }; 40 41 void __user *io_buffer_select(struct io_kiocb *req, size_t *len, 42 unsigned int issue_flags); 43 void io_destroy_buffers(struct io_ring_ctx *ctx); 44 45 int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 46 int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags); 47 48 int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); 49 int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags); 50 51 int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 52 int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); 53 54 unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); 55 56 bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); 57 58 void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid); 59 60 static inline bool io_kbuf_recycle_ring(struct io_kiocb *req) 61 { 62 /* 63 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear 64 * the flag and hence ensure that bl->head doesn't get incremented. 65 * If the tail has already been incremented, hang on to it. 66 * The exception is partial io, that case we should increment bl->head 67 * to monopolize the buffer. 68 */ 69 if (req->buf_list) { 70 if (req->flags & REQ_F_PARTIAL_IO) { 71 /* 72 * If we end up here, then the io_uring_lock has 73 * been kept held since we retrieved the buffer. 74 * For the io-wq case, we already cleared 75 * req->buf_list when the buffer was retrieved, 76 * hence it cannot be set here for that case. 77 */ 78 req->buf_list->head++; 79 req->buf_list = NULL; 80 } else { 81 req->buf_index = req->buf_list->bgid; 82 req->flags &= ~REQ_F_BUFFER_RING; 83 return true; 84 } 85 } 86 return false; 87 } 88 89 static inline bool io_do_buffer_select(struct io_kiocb *req) 90 { 91 if (!(req->flags & REQ_F_BUFFER_SELECT)) 92 return false; 93 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); 94 } 95 96 static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) 97 { 98 if (req->flags & REQ_F_BUFFER_SELECTED) 99 return io_kbuf_recycle_legacy(req, issue_flags); 100 if (req->flags & REQ_F_BUFFER_RING) 101 return io_kbuf_recycle_ring(req); 102 return false; 103 } 104 105 static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req, 106 struct list_head *list) 107 { 108 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); 109 110 if (req->flags & REQ_F_BUFFER_RING) { 111 if (req->buf_list) { 112 req->buf_index = req->buf_list->bgid; 113 req->buf_list->head++; 114 } 115 req->flags &= ~REQ_F_BUFFER_RING; 116 } else { 117 req->buf_index = req->kbuf->bgid; 118 list_add(&req->kbuf->list, list); 119 req->flags &= ~REQ_F_BUFFER_SELECTED; 120 } 121 122 return ret; 123 } 124 125 static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) 126 { 127 lockdep_assert_held(&req->ctx->completion_lock); 128 129 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 130 return 0; 131 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp); 132 } 133 134 static inline unsigned int io_put_kbuf(struct io_kiocb *req, 135 unsigned issue_flags) 136 { 137 138 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 139 return 0; 140 return __io_put_kbuf(req, issue_flags); 141 } 142 #endif 143