linux/io_uring/rw.h
Jens Axboe a9165b83c1 io_uring/rw: always setup io_async_rw for read/write requests
read/write requests try to put everything on the stack, and then alloc
and copy if a retry is needed. This necessitates a bunch of nasty code
that deals with intermediate state.

Get rid of this, and have the prep side setup everything that is needed
upfront, which greatly simplifies the opcode handlers.

This includes adding an alloc cache for io_async_rw, to make it cheap
to handle.

In terms of cost, this should be basically free and transparent. For
the worst case of {READ,WRITE}_FIXED which didn't need it before,
performance is unaffected in the normal peak workload that is being
used to test that. Still runs at 122M IOPS.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15 08:10:25 -06:00

35 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/pagemap.h>
struct io_rw_state {
struct iov_iter iter;
struct iov_iter_state iter_state;
struct iovec fast_iov[UIO_FASTIOV];
};
struct io_async_rw {
union {
size_t bytes_done;
struct io_cache_entry cache;
};
struct io_rw_state s;
struct iovec *free_iovec;
struct wait_page_queue wpq;
};
int io_prep_read_fixed(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_prep_write_fixed(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_prep_readv(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_prep_writev(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_prep_read(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_prep_write(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_read(struct io_kiocb *req, unsigned int issue_flags);
int io_write(struct io_kiocb *req, unsigned int issue_flags);
void io_readv_writev_cleanup(struct io_kiocb *req);
void io_rw_fail(struct io_kiocb *req);
void io_req_rw_complete(struct io_kiocb *req, struct io_tw_state *ts);
int io_read_mshot_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags);
void io_rw_cache_free(struct io_cache_entry *entry);