Re: [PATCH v4] nvme/069: add a test for multipath cdev lifetime

On 7/16/26 1:59 PM, John Garry wrote:
> +#include <inttypes.h>
> +#include <sys/ioctl.h>
> +#include <linux/types.h>
> +
> +#ifndef _LINUX_NVME_IOCTL_H
> +#define _LINUX_NVME_IOCTL_H
> +#define NVME_IOCTL_ID		_IO('N', 0x40)
> +#endif /* _UAPI_LINUX_NVME_IOCTL_H */
> +
> +int main(int argc, char **argv)
> +{
> +	int fd, fd1;
> +	int count;
> +
> +	if (argc < 2) {
> +		fprintf(stderr, "usage: %s /dev/ngXnX", argv[0]);
> +		return EINVAL;
> +	}
> +
> +	fd = open(argv[1], O_RDONLY);
> +	if (fd < 0)
> +		return fd;
> +
> +	/*
> +	 * Steps:
> +	 * a. Signal to parent that we have opened the file so that it may
> +	 *    start the teardown.
> +	 * b. Try to open device until disallowed/gone.
> +	 * c. Sleep to allow nvme-subsystem be torn down.
> +	 * d. Issue the ioctl on original fd.
> +	 */
> +	kill(getppid(), SIGUSR2);
> +	count = 0;
> +	for (;;) {
> +		fd1 = open(argv[1], O_RDONLY);
> +		usleep(500000);
> +		if (fd1 < 0)
> +			break;

Does it make sense to check for errno set to ENODEV or ENOENT
before breaking out here?

Thanks,
--Nilay