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 atomic_t refs; 29 30 /* ring mapped provided buffers */ 31 __u8 is_mapped; 32 /* ring mapped provided buffers, but mmap'ed by application */ 33 __u8 is_mmap; 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 unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags); 58 59 void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags); 60 61 void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl); 62 struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx, 63 unsigned long bgid); 64 int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma); 65 io_kbuf_recycle_ring(struct io_kiocb * req)66 static inline void 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 } 90 } 91 } 92 io_do_buffer_select(struct io_kiocb * req)93 static inline bool io_do_buffer_select(struct io_kiocb *req) 94 { 95 if (!(req->flags & REQ_F_BUFFER_SELECT)) 96 return false; 97 return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); 98 } 99 io_kbuf_recycle(struct io_kiocb * req,unsigned issue_flags)100 static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) 101 { 102 if (req->flags & REQ_F_BUFFER_SELECTED) 103 io_kbuf_recycle_legacy(req, issue_flags); 104 if (req->flags & REQ_F_BUFFER_RING) 105 io_kbuf_recycle_ring(req); 106 } 107 __io_put_kbuf_list(struct io_kiocb * req,struct list_head * list)108 static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req, 109 struct list_head *list) 110 { 111 unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); 112 113 if (req->flags & REQ_F_BUFFER_RING) { 114 if (req->buf_list) { 115 req->buf_index = req->buf_list->bgid; 116 req->buf_list->head++; 117 } 118 req->flags &= ~REQ_F_BUFFER_RING; 119 } else { 120 req->buf_index = req->kbuf->bgid; 121 list_add(&req->kbuf->list, list); 122 req->flags &= ~REQ_F_BUFFER_SELECTED; 123 } 124 125 return ret; 126 } 127 io_put_kbuf_comp(struct io_kiocb * req)128 static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) 129 { 130 lockdep_assert_held(&req->ctx->completion_lock); 131 132 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 133 return 0; 134 return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp); 135 } 136 io_put_kbuf(struct io_kiocb * req,unsigned issue_flags)137 static inline unsigned int io_put_kbuf(struct io_kiocb *req, 138 unsigned issue_flags) 139 { 140 141 if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) 142 return 0; 143 return __io_put_kbuf(req, issue_flags); 144 } 145 #endif 146