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 57 void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx); 58 59 unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); 60 61 void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); 62 63 void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid); 64 65 static inline void io_kbuf_recycle_ring(struct io_kiocb *req) 66 { 67 /* 68 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear 69 * the flag and hence ensure that bl->head doesn't get incremented. 70 * If the tail has already been incremented, hang on to it. 71 * The exception is partial io, that case we should increment bl->head 72 * to monopolize the buffer. 73 */ 74 if (req->buf_list) { 75 if (req->flags & REQ_F_PARTIAL_IO) { 76 /* 77 * If we end up here, then the io_uring_lock has 78 * been kept held since we retrieved the buffer. 79 * For the io-wq case, we already cleared 80 * req->buf_list when the buffer was retrieved, 81 * hence it cannot be set here for that case. 82 */ 83 req->buf_list->head++; 84 req->buf_list = NULL; 85 } else { 86 req->buf_index = req->buf_list->bgid; 87 req->flags &= ~REQ_F_BUFFER_RING; 88 } 89 } 90 } 91 92 static inline bool io_do_buffer_select(struct io_kiocb *req) 93 { 94 if (!(req->flags & REQ_F_BUFFER_SELECT)) 95 return false; 96 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); 97 } 98 99 static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) 100 { 101 if (req->flags & REQ_F_BUFFER_SELECTED) 102 io_kbuf_recycle_legacy(req, issue_flags); 103 if (req->flags & REQ_F_BUFFER_RING) 104 io_kbuf_recycle_ring(req); 105 } 106 107 static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req, 108 struct list_head *list) 109 { 110 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); 111 112 if (req->flags & REQ_F_BUFFER_RING) { 113 if (req->buf_list) { 114 req->buf_index = req->buf_list->bgid; 115 req->buf_list->head++; 116 } 117 req->flags &= ~REQ_F_BUFFER_RING; 118 } else { 119 req->buf_index = req->kbuf->bgid; 120 list_add(&req->kbuf->list, list); 121 req->flags &= ~REQ_F_BUFFER_SELECTED; 122 } 123 124 return ret; 125 } 126 127 static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) 128 { 129 lockdep_assert_held(&req->ctx->completion_lock); 130 131 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 132 return 0; 133 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp); 134 } 135 136 static inline unsigned int io_put_kbuf(struct io_kiocb *req, 137 unsigned issue_flags) 138 { 139 140 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 141 return 0; 142 return __io_put_kbuf(req, issue_flags); 143 } 144 #endif 145