Comment by jcoffland

Maybe I just missed this but can anyone tell me what kernel versions support io_uring. I ran the following test program on 4.19.0 and it is not supported:

    #include <stdio.h>
    #include <stdlib.h>
    #include <sys/utsname.h>
    #include <liburing.h>
    #include <liburing/io_uring.h>


    static const char *op_strs[] = {
      "IORING_OP_NOP",
      "IORING_OP_READV",
      "IORING_OP_WRITEV",
      "IORING_OP_FSYNC",
      "IORING_OP_READ_FIXED",
      "IORING_OP_WRITE_FIXED",
      "IORING_OP_POLL_ADD",
      "IORING_OP_POLL_REMOVE",
      "IORING_OP_SYNC_FILE_RANGE",
      "IORING_OP_SENDMSG",
      "IORING_OP_RECVMSG",
      "IORING_OP_TIMEOUT",
      "IORING_OP_TIMEOUT_REMOVE",
      "IORING_OP_ACCEPT",
      "IORING_OP_ASYNC_CANCEL",
      "IORING_OP_LINK_TIMEOUT",
      "IORING_OP_CONNECT",
      "IORING_OP_FALLOCATE",
      "IORING_OP_OPENAT",
      "IORING_OP_CLOSE",
      "IORING_OP_FILES_UPDATE",
      "IORING_OP_STATX",
      "IORING_OP_READ",
      "IORING_OP_WRITE",
      "IORING_OP_FADVISE",
      "IORING_OP_MADVISE",
      "IORING_OP_SEND",
      "IORING_OP_RECV",
      "IORING_OP_OPENAT2",
      "IORING_OP_EPOLL_CTL",
      "IORING_OP_SPLICE",
      "IORING_OP_PROVIDE_BUFFERS",
      "IORING_OP_REMOVE_BUFFERS",
    };


    int main() {
      struct utsname u;
      uname(&u);

      struct io_uring_probe *probe = io_uring_get_probe();
      if (!probe) {
        printf("Kernel %s does not support io_uring.\n", u.release);
        return 0;
      }

      printf("List of kernel %s's supported io_uring operations:\n", u.release);

      for (int i = 0; i < IORING_OP_LAST; i++ ) {
        const char *answer = io_uring_opcode_supported(probe, i) ? "yes" : "no";
        printf("%s: %s\n", op_strs[i], answer);
      }

      free(probe);
      return 0;
    }