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