After the upgrade, why can't an instance be created with params.flags=IORING_SETUP_SINGLE_ISSUER? What's the issue?

[sxstd001]

    io_uring ring{};
    io_uring_params params {};
    params.flags |= IORING_SETUP_SINGLE_ISSUER;  // if use this flag, it's error;
    auto ret = io_uring_queue_init_params(256, &ring, &params);

error: Invalid argument.

It was normal before the upgrade;

[RogerMarcoHernandez]

@sxstd001 I can’t reproduce your problem with 6.9 linux kernel version and 2.6 liburing version.

#include <liburing.h>

#include <stdio.h>
#include <string.h>

int main (void)
{
    io_uring ring{};
    io_uring_params params{};
    params.flags |= IORING_SETUP_SINGLE_ISSUER;
    const auto ret = io_uring_queue_init_params (256, &ring, &params);
    if (ret != 0)
        printf ("error: %s", strerror (ret));           

    io_uring_queue_exit (&ring);

    return ret != 0;
}

Could you please specify both versions you are using and within which conditions you are getting the error? On the other side, is there any more code than the one you provided in your program?

[axboe]

Please try and strace that, makes no sense. Unless you're on an old kernel that doesn't support IORING_SETUP_SINGLE_ISSUER, in which case it would indeed return -EINVAL.

[sxstd001]

@sxstd001 I can’t reproduce your problem with 6.9 linux kernel version and 2.6 liburing version.

#include <liburing.h>

#include <stdio.h>
#include <string.h>

int main (void)
{
  io_uring ring{};
  io_uring_params params{};
  params.flags |= IORING_SETUP_SINGLE_ISSUER;
  const auto ret = io_uring_queue_init_params (256, &ring, &params);
  if (ret != 0)
      printf ("error: %s", strerror (ret));           

  io_uring_queue_exit (&ring);

  return ret != 0;
}

Could you please specify both versions you are using and within which conditions you are getting the error? On the other side, is there any more code than the one you provided in your program?

[sxstd001]

ArchLinux latest version;
liburing-2.6-2;

[axboe]

Works fine here, please provide an strace output of running that as requested.