[LTP] [PATCH] tst_device: Scan /sys/block/* for stat file

[Yang Xu]

Hi
> The current tst_dev_bytes_written() function works only for simple cases
> where the block device is not divided into partitions. This patch fixes
> that scannning the sysfiles for pattern /sys/block/*/devname/stat.
> 
> Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
> CC: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
> CC: Sumit Garg <sumit.garg@linaro.org>
> ---
>   lib/tst_device.c | 33 ++++++++++++++++++++++++++++-----
>   1 file changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/tst_device.c b/lib/tst_device.c
> index 10f71901d..aca769559 100644
> --- a/lib/tst_device.c
> +++ b/lib/tst_device.c
> @@ -373,16 +373,39 @@ int tst_umount(const char *path)
>   	return -1;
>   }
>   
> +int find_stat_file(const char *dev, char *path, size_t path_len)
> +{
> +	const char *devname = strrchr(dev, '/') + 1;
> +
> +	snprintf(path, path_len, "/sys/block/%s/stat", devname);
> +
> +	if (!access(path, F_OK))
> +		return 1;
> +
> +	DIR *dir = SAFE_OPENDIR(NULL, "/sys/block/");
> +	struct dirent *ent;
> +
> +	while ((ent = readdir(dir))) {
> +		snprintf(path, path_len, "/sys/block/%s/%s/stat", ent->d_name, devname);
> +
> +		fprintf(stderr, "%s\n", path);
> +
It will make many noise when using .all_filesystem and we can remove it. 
Other than, it looks good to me.
> +		if (!access(path, F_OK)) {
> +			SAFE_CLOSEDIR(NULL, dir);
> +			return 1;
> +		}
> +	}
> +
> +	SAFE_CLOSEDIR(NULL, dir);
> +	return 0;
> +}
> +
>   unsigned long tst_dev_bytes_written(const char *dev)
>   {
> -	struct stat st;
>   	unsigned long dev_sec_write = 0, dev_bytes_written, io_ticks = 0;
>   	char dev_stat_path[1024];
>   
> -	snprintf(dev_stat_path, sizeof(dev_stat_path), "/sys/block/%s/stat",
> -		 strrchr(dev, '/') + 1);
> -
> -	if (stat(dev_stat_path, &st) != 0)
> +	if (!find_stat_file(dev, dev_stat_path, sizeof(dev_stat_path)))
>   		tst_brkm(TCONF, NULL, "Test device stat file: %s not found",
>   			 dev_stat_path);
>   
>