forked from Minki/linux
4ab9d46507
In commit 934447a603 ("io_uring: do not recycle buffer in READV") a
temporary fix was put in io_kbuf_recycle to simply never recycle READV
buffers.
Instead of that, rather treat READV with REQ_F_BUFFER_SELECTED the same as
a READ with REQ_F_BUFFER_SELECTED. Since READV requires iov_len of 1 they
are essentially the same.
In order to do this inside io_prep_rw() add some validation to check that
it is in fact only length 1, and also extract the length of the buffer at
prep time.
This allows removal of the io_iov_buffer_select codepaths as they are only
used from the READV op.
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220907165152.994979-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#ifndef IOU_KBUF_H
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#define IOU_KBUF_H
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#include <uapi/linux/io_uring.h>
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struct io_buffer_list {
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/*
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* If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
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* then these are classic provided buffers and ->buf_list is used.
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*/
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union {
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struct list_head buf_list;
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struct {
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struct page **buf_pages;
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struct io_uring_buf_ring *buf_ring;
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};
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};
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__u16 bgid;
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/* below is for ring provided buffers */
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__u16 buf_nr_pages;
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__u16 nr_entries;
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__u16 head;
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__u16 mask;
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};
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struct io_buffer {
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struct list_head list;
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__u64 addr;
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__u32 len;
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__u16 bid;
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__u16 bgid;
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};
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void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
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unsigned int issue_flags);
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void io_destroy_buffers(struct io_ring_ctx *ctx);
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int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags);
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int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
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int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
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int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
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unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
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void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
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static inline void io_kbuf_recycle_ring(struct io_kiocb *req)
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{
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/*
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* We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
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* the flag and hence ensure that bl->head doesn't get incremented.
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* If the tail has already been incremented, hang on to it.
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* The exception is partial io, that case we should increment bl->head
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* to monopolize the buffer.
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*/
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if (req->buf_list) {
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if (req->flags & REQ_F_PARTIAL_IO) {
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/*
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* If we end up here, then the io_uring_lock has
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* been kept held since we retrieved the buffer.
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* For the io-wq case, we already cleared
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* req->buf_list when the buffer was retrieved,
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* hence it cannot be set here for that case.
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*/
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req->buf_list->head++;
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req->buf_list = NULL;
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} else {
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req->buf_index = req->buf_list->bgid;
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req->flags &= ~REQ_F_BUFFER_RING;
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}
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}
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}
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static inline bool io_do_buffer_select(struct io_kiocb *req)
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{
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if (!(req->flags & REQ_F_BUFFER_SELECT))
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return false;
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return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
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}
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static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
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{
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if (req->flags & REQ_F_BUFFER_SELECTED)
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io_kbuf_recycle_legacy(req, issue_flags);
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if (req->flags & REQ_F_BUFFER_RING)
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io_kbuf_recycle_ring(req);
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}
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static inline unsigned int __io_put_kbuf_list(struct io_kiocb *req,
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struct list_head *list)
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{
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unsigned int ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
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if (req->flags & REQ_F_BUFFER_RING) {
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if (req->buf_list) {
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req->buf_index = req->buf_list->bgid;
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req->buf_list->head++;
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}
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req->flags &= ~REQ_F_BUFFER_RING;
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} else {
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req->buf_index = req->kbuf->bgid;
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list_add(&req->kbuf->list, list);
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req->flags &= ~REQ_F_BUFFER_SELECTED;
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}
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return ret;
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}
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static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
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{
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lockdep_assert_held(&req->ctx->completion_lock);
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if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
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return 0;
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return __io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
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}
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static inline unsigned int io_put_kbuf(struct io_kiocb *req,
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unsigned issue_flags)
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{
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if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
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return 0;
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return __io_put_kbuf(req, issue_flags);
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}
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#endif
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