Re: [RFC] Easier printing of unknown-size quantities

[Joe Perches <joe@perches.com>]

On Thu, 2014-01-09 at 06:42 -0700, Matthew Wilcox wrote:
> We have a number of types whose sizes are architecture- or
> config-dependent such as pgoff_t or sector_t.  The recommendation for
> printing them is to cast them to (unsigned long long) and print them with
> %Lu/%llx/...  That's entirely reasonable except that it's so verbose.
[]
> diff --git a/fs/buffer.c b/fs/buffer.c
[]
> @@ -148,7 +148,7 @@ static void buffer_io_error(struct buffer_head *bh)
>  {
>  	char b[BDEVNAME_SIZE];
>  	printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
> -			bdevname(bh->b_bdev, b),
> -			(unsigned long long)bh->b_blocknr);
> +			bdevname(bh->b_bdev, b), ULL(bh->b_blocknr));
>  }
 
casting to u64 works and is also simpler

	printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
			bdevname(bh->b_bdev, b), (u64)bh->b_blocknr);