[LTP] [PATCH v2] ioctl_loop06: update loopback block size validation

[Luis Chamberlain]

On Thu, Mar 13, 2025 at 05:24:45PM +0800, Li Wang wrote:
> The kernel commit 47dd6753 ("block/bdev: lift block size restrictions to 64k")
> now supports block sizes larger than PAGE_SIZE, with a new upper limit of
> BLK_MAX_BLOCK_SIZE (64K). But ioctl_loop06 still assumes that PAGE_SIZE is the
> maximum allowed block size, causing failures on newer kernels(>= 6.14):
> 
>   ioctl_loop06.c:74: TINFO: Using LOOP_SET_BLOCK_SIZE with arg > PAGE_SIZE
>   ioctl_loop06.c:57: TFAIL: Set block size succeed unexpectedly
>   ...
>   ioctl_loop06.c:74: TINFO: Using LOOP_CONFIGURE with block_size > PAGE_SIZE
>   ioctl_loop06.c:57: TFAIL: Set block size succeed unexpectedly
> 
> This patch updates ioctl_loop06 to use BLK_MAX_BLOCK_SIZE instead of PAGE_SIZE
> for block size validation.
> 
> And, we give up the test size between (PAGE_SIZE, BLK_MAX_BLOCK_SIZE) even on
> old kernels becase it makes no sense.
> 
> Signed-off-by: Li Wang <liwang@redhat.com>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.de>
> ---
>  testcases/kernel/syscalls/ioctl/ioctl_loop06.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_loop06.c b/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> index 573871bc1..238a7c6f5 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> @@ -17,6 +17,8 @@
>  #include "lapi/loop.h"
>  #include "tst_test.h"
>  
> +#define BLK_MAX_BLOCK_SIZE 0x00010000 /* SZ_64K */

Today its SZ_64K, tomorrow another value. If you have an ifdef check for
kernel versions it may be good to do that. So if >= v6.15 then 64k
othersize PAGE_SIZE is fine.

> +
>  static char dev_path[1024];
>  static int dev_num, dev_fd, file_fd, attach_flag, loop_configure_sup = 1;
>  static unsigned int invalid_value, half_value, unalign_value;
> @@ -31,7 +33,7 @@ static struct tcase {
>  	"Using LOOP_SET_BLOCK_SIZE with arg < 512"},
>  
>  	{&invalid_value, LOOP_SET_BLOCK_SIZE,
> -	"Using LOOP_SET_BLOCK_SIZE with arg > PAGE_SIZE"},
> +	"Using LOOP_SET_BLOCK_SIZE with arg > BLK_MAX_BLOCK_SIZE"},
>  
>  	{&unalign_value, LOOP_SET_BLOCK_SIZE,
>  	"Using LOOP_SET_BLOCK_SIZE with arg != power_of_2"},
> @@ -40,7 +42,7 @@ static struct tcase {
>  	"Using LOOP_CONFIGURE with block_size < 512"},
>  
>  	{&invalid_value, LOOP_CONFIGURE,
> -	"Using LOOP_CONFIGURE with block_size > PAGE_SIZE"},
> +	"Using LOOP_CONFIGURE with block_size > BLK_MAX_BLOCK_SIZE"},
>  
>  	{&unalign_value, LOOP_CONFIGURE,
>  	"Using LOOP_CONFIGURE with block_size != power_of_2"},
> @@ -106,7 +108,7 @@ static void setup(void)
>  	tst_fill_file("test.img", 0, 1024, 1024);
>  	half_value = 256;
>  	pg_size = getpagesize();
> -	invalid_value = pg_size * 2 ;
> +	invalid_value = BLK_MAX_BLOCK_SIZE + 1;

I'd use BLK_MAX_BLOCK_SIZE * 2 as we use power of 2 values;

  Luis