Re: [PATCH v2] btrfs: make block group flags in balance printks human-readable

["Holger Hoffstätte" <holger@applied-asynchrony.com>]

On 11/07/16 22:40, Adam Borowski wrote:
> They're not even documented anywhere, letting users with no recourse but
> to RTFS.  It's no big burden to output the bitfield as words.
> 
> Also, display unknown flags as hex.
> 
> Signed-off-by: Adam Borowski <kilobyte@angband.pl>
[..]
>  
>  /*
> + * explain bit flags, prefixed by a '|' that'll be dropped
> + */
> +static char *describe_block_group_flags(char *buf, u64 flags)
> +{
> +#define BUF_SIZE 128
> +	char *buf0 = buf = kmalloc(BUF_SIZE, GFP_NOFS);
[..]

Maybe I'm missing some clever (?) trick here, but what's the point of passing
in a potentially uninitialized 'buf' when it's immediately reassigned locally,
and a new value is returned and assigned at the call site?
IMHO you'd probably either want to pass the buffer in or return it, but not
both - and in that case the allocation should probably be hoisted out
into the caller as well, if only to make things a bit more symmetric.

-h