[LTP] [PATCH] zram/zram03.c: Fix obsolete zram status files

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

Hi Petr,

Could you help me review this patch? :-)

Thanks,
Xiao Yang
On 2018/07/12 16:56, Xiao Yang wrote:
> Since kernel commit c87d1655c295, separate zram status files("compr_data_size",
> "num_reads" etc.) which can be accessed via one of zram<id>/stat or
> zram<id>/io_stat or zram<id>/mm_stat were removed.
>
> This commit broke zram03, as below:
> ----------------------------------------------------------------------
> safe_file_ops.c:144: Failed to open FILE '/sys/block/zram0/compr_data_size'
> for reading at zram03.c:181: errno=ENOENT(2): No such file or directory
> ----------------------------------------------------------------------
>
> Also, zero pages in zram<id>/mm_stat was extended to same element pages
> since kernel commit 8e19d540d107.
>
> We try to get requested zram status by zram<id>/stat and zram<id>/mm_stat
> if separate zram status files don't exist.
>
> URL for detailed zram status:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/blockdev/zram.txt
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/block/stat.txt
>
> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> ---
>  testcases/kernel/device-drivers/zram/zram03.c | 50 +++++++++++++++++++++++----
>  1 file changed, 44 insertions(+), 6 deletions(-)
>
> diff --git a/testcases/kernel/device-drivers/zram/zram03.c b/testcases/kernel/device-drivers/zram/zram03.c
> index 3f7ab4e..06995fd 100644
> --- a/testcases/kernel/device-drivers/zram/zram03.c
> +++ b/testcases/kernel/device-drivers/zram/zram03.c
> @@ -40,6 +40,9 @@ char *TCID = "zram03";
>  int TST_TOTAL = 1;
>  
>  #define PATH_ZRAM	"/sys/block/zram0"
> +#define OBSOLETE_ZRAM_FILE	"/sys/block/zram0/num_reads"
> +#define PATH_ZRAM_STAT	"/sys/block/zram0/stat"
> +#define PATH_ZRAM_MM_STAT	"/sys/block/zram0/mm_stat"
>  #define SIZE		(512 * 1024 * 1024L)
>  #define DEVICE		"/dev/zram0"
>  
> @@ -182,14 +185,49 @@ static void print(char *string)
>  	tst_resm(TINFO, "%s is %s", filename, value);
>  }
>  
> +static void print_stat(char *nread, char *nwrite)
> +{
> +	char nread_val[BUFSIZ], nwrite_val[BUFSIZ];
> +
> +	SAFE_FILE_SCANF(cleanup, PATH_ZRAM_STAT, "%s %*s %*s %*s %s",
> +			nread_val, nwrite_val);
> +	tst_resm(TINFO, "%s from %s is %s", nread, PATH_ZRAM_STAT,
> +		 nread_val);
> +	tst_resm(TINFO, "%s from %s is %s", nwrite, PATH_ZRAM_STAT,
> +		 nwrite_val);
> +}
> +
> +static void print_mm_stat(char *orig, char *compr, char *mem, char *zero)
> +{
> +	char orig_val[BUFSIZ], compr_val[BUFSIZ];
> +	char mem_val[BUFSIZ], zero_val[BUFSIZ];
> +
> +	SAFE_FILE_SCANF(cleanup, PATH_ZRAM_MM_STAT, "%s %s %s %*s %*s %s",
> +			orig_val, compr_val, mem_val, zero_val);
> +	tst_resm(TINFO, "%s from %s is %s", orig, PATH_ZRAM_MM_STAT,
> +		 orig_val);
> +	tst_resm(TINFO, "%s from %s is %s", compr, PATH_ZRAM_MM_STAT,
> +		compr_val);
> +	tst_resm(TINFO, "%s from %s is %s", mem, PATH_ZRAM_MM_STAT,
> +		 mem_val);
> +	tst_resm(TINFO, "%s from %s is %s", zero, PATH_ZRAM_MM_STAT,
> +		 zero_val);
> +}
> +
>  static void dump_info(void)
>  {
>  	print("initstate");
> -	print("compr_data_size");
> -	print("orig_data_size");
>  	print("disksize");
> -	print("mem_used_total");
> -	print("num_reads");
> -	print("num_writes");
> -	print("zero_pages");
> +	if (!access(OBSOLETE_ZRAM_FILE, F_OK)) {
> +		print("orig_data_size");
> +		print("compr_data_size");
> +		print("mem_used_total");
> +		print("zero_pages");
> +		print("num_reads");
> +		print("num_writes");
> +	} else {
> +		print_mm_stat("orig_data_size", "compr_data_size",
> +			      "mem_used_total", "zero/same_pages");
> +		print_stat("num_reads", "num_writes");
> +	}
>  }