diff options
Diffstat (limited to 'io_uring/kbuf.h')
| -rw-r--r-- | io_uring/kbuf.h | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h new file mode 100644 index 000000000000..9da3a933ef40 --- /dev/null +++ b/io_uring/kbuf.h @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef IOU_KBUF_H +#define IOU_KBUF_H + +#include <uapi/linux/io_uring.h> + +struct io_buffer_list { + /* + * If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not, + * then these are classic provided buffers and ->buf_list is used. + */ + union { + struct list_head buf_list; + struct { + struct page **buf_pages; + struct io_uring_buf_ring *buf_ring; + }; + }; + __u16 bgid; + + /* below is for ring provided buffers */ + __u16 buf_nr_pages; + __u16 nr_entries; + __u16 head; + __u16 mask; +}; + +struct io_buffer { + struct list_head list; + __u64 addr; + __u32 len; + __u16 bid; + __u16 bgid; +}; + +void __user *io_buffer_select(struct io_kiocb *req, size_t *len, + unsigned int issue_flags); +void __io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags); +void io_destroy_buffers(struct io_ring_ctx *ctx); + +int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags); + +int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags); + +int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); +int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg); + +static inline bool io_do_buffer_select(struct io_kiocb *req) +{ + if (!(req->flags & REQ_F_BUFFER_SELECT)) + return false; + return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)); +} + +static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) +{ + if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) + return; + /* + * For legacy provided buffer mode, don't recycle if we already did + * IO to this buffer. For ring-mapped provided buffer mode, we should + * increment ring->head to explicitly monopolize the buffer to avoid + * multiple use. + */ + if ((req->flags & REQ_F_BUFFER_SELECTED) && + (req->flags & REQ_F_PARTIAL_IO)) + return; + + /* + * READV uses fields in `struct io_rw` (len/addr) to stash the selected + * buffer data. However if that buffer is recycled the original request + * data stored in addr is lost. Therefore forbid recycling for now. + */ + if (req->opcode == IORING_OP_READV) + return; + + __io_kbuf_recycle(req, issue_flags); +} + +static unsigned int __io_put_kbuf(struct io_kiocb *req, struct list_head *list) +{ + if (req->flags & REQ_F_BUFFER_RING) { + if (req->buf_list) + req->buf_list->head++; + req->flags &= ~REQ_F_BUFFER_RING; + } else { + list_add(&req->kbuf->list, list); + req->flags &= ~REQ_F_BUFFER_SELECTED; + } + + return IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT); +} + +static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) +{ + lockdep_assert_held(&req->ctx->completion_lock); + + if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) + return 0; + return __io_put_kbuf(req, &req->ctx->io_buffers_comp); +} + +static inline unsigned int io_put_kbuf(struct io_kiocb *req, + unsigned issue_flags) +{ + unsigned int cflags; + + if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))) + return 0; + + /* + * We can add this buffer back to two lists: + * + * 1) The io_buffers_cache list. This one is protected by the + * ctx->uring_lock. If we already hold this lock, add back to this + * list as we can grab it from issue as well. + * 2) The io_buffers_comp list. This one is protected by the + * ctx->completion_lock. + * + * We migrate buffers from the comp_list to the issue cache list + * when we need one. + */ + if (req->flags & REQ_F_BUFFER_RING) { + /* no buffers to recycle for this case */ + cflags = __io_put_kbuf(req, NULL); + } else if (issue_flags & IO_URING_F_UNLOCKED) { + struct io_ring_ctx *ctx = req->ctx; + + spin_lock(&ctx->completion_lock); + cflags = __io_put_kbuf(req, &ctx->io_buffers_comp); + spin_unlock(&ctx->completion_lock); + } else { + lockdep_assert_held(&req->ctx->uring_lock); + + cflags = __io_put_kbuf(req, &req->ctx->io_buffers_cache); + } + + return cflags; +} +#endif |