Commit 5769a351 authored by Jiufei Xue's avatar Jiufei Xue Committed by Jens Axboe
Browse files

io_uring: change the poll type to be 32-bits 



poll events should be 32-bits to cover EPOLLEXCLUSIVE.

Explicit word-swap the poll32_events for big endian to make sure the ABI
is not changed.  We call this feature IORING_FEAT_POLL_32BITS,
applications who want to use EPOLLEXCLUSIVE should check the feature bit
first.

Signed-off-by: default avatarJiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 48778464

fs/io_uring.c

+9 −4
Original line number Diff line number Diff line
@@ -4589,7 +4589,7 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, 
static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)

{

	struct io_poll_iocb *poll = &req->poll;

	u16 events;

	u32 events;



	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))

		return -EINVAL;
@@ -4598,7 +4598,10 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe 
	if (!poll->file)

		return -EBADF;



	events = READ_ONCE(sqe->poll_events);

	events = READ_ONCE(sqe->poll32_events);

#ifdef __BIG_ENDIAN

	events = swahw32(events);

#endif

	poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;



	io_get_req_task(req);
@@ -7928,7 +7931,8 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p, 


	p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |

			IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |

			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL;

			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |

			IORING_FEAT_POLL_32BITS;



	if (copy_to_user(params, p, sizeof(*p))) {

		ret = -EFAULT;
@@ -8217,7 +8221,8 @@ static int __init io_uring_init(void) 
	BUILD_BUG_SQE_ELEM(28, /* compat */   int, rw_flags);

	BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);

	BUILD_BUG_SQE_ELEM(28, __u32,  fsync_flags);

	BUILD_BUG_SQE_ELEM(28, __u16,  poll_events);

	BUILD_BUG_SQE_ELEM(28, /* compat */ __u16,  poll_events);

	BUILD_BUG_SQE_ELEM(28, __u32,  poll32_events);

	BUILD_BUG_SQE_ELEM(28, __u32,  sync_range_flags);

	BUILD_BUG_SQE_ELEM(28, __u32,  msg_flags);

	BUILD_BUG_SQE_ELEM(28, __u32,  timeout_flags);

include/uapi/linux/io_uring.h

+3 −1
Original line number Diff line number Diff line
@@ -31,7 +31,8 @@ struct io_uring_sqe { 
	union {

		__kernel_rwf_t	rw_flags;

		__u32		fsync_flags;

		__u16		poll_events;

		__u16		poll_events;	/* compatibility */

		__u32		poll32_events;	/* word-reversed for BE */

		__u32		sync_range_flags;

		__u32		msg_flags;

		__u32		timeout_flags;
@@ -248,6 +249,7 @@ struct io_uring_params { 
#define IORING_FEAT_RW_CUR_POS		(1U << 3)

#define IORING_FEAT_CUR_PERSONALITY	(1U << 4)

#define IORING_FEAT_FAST_POLL		(1U << 5)

#define IORING_FEAT_POLL_32BITS 	(1U << 6)



/*

 * io_uring_register(2) opcodes and arguments

tools/io_uring/liburing.h

+5 −1
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ extern "C" { 
#include <string.h>

#include "../../include/uapi/linux/io_uring.h"

#include <inttypes.h>

#include <linux/swab.h>

#include "barrier.h"



/*
@@ -145,11 +146,14 @@ static inline void io_uring_prep_write_fixed(struct io_uring_sqe *sqe, int fd, 
}



static inline void io_uring_prep_poll_add(struct io_uring_sqe *sqe, int fd,

					  short poll_mask)

					  unsigned poll_mask)

{

	memset(sqe, 0, sizeof(*sqe));

	sqe->opcode = IORING_OP_POLL_ADD;

	sqe->fd = fd;

#if __BYTE_ORDER == __BIG_ENDIAN

	poll_mask = __swahw32(poll_mask);

#endif

	sqe->poll_events = poll_mask;

}