Re: [PATCH 1/2] [v2] lib/hexdump: introduce DUMP_PREFIX_UNHASHED for unhashed addresses

From: Timur Tabi <timur@kernel.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Petr Mladek <pmladek@suse.com>,
	roman.fietze@magna.com, Kees Cook <keescook@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	John Ogness <john.ogness@linutronix.de>,
	linux-mm <linux-mm@kvack.org>,
	Akinobu Mita <akinobu.mita@gmail.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Vaibhav Jain <vaibhav@linux.ibm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 1/2] [v2] lib/hexdump: introduce DUMP_PREFIX_UNHASHED for unhashed addresses
Date: Mon, 18 Jan 2021 09:57:55 -0600	[thread overview]
Message-ID: <b39866a4-19cd-879b-1f3e-44126caf9193@kernel.org> (raw)
In-Reply-To: <CAHp75Vdk6y8dGNJOswZwfOeva_sqVcw-f=yYgf_rptjHXxfZvw@mail.gmail.com>

On 1/18/21 4:03 AM, Andy Shevchenko wrote:
> On Sun, Jan 17, 2021 at 12:12 AM Timur Tabi <timur@kernel.org> wrote:
> 
> (Hint: -v<n> to the git format-patch will create a versioned subject
> prefix for you automatically)

I like to keep the version in the git repo  itself so that I don't need 
to keep track of it separately, but thanks for the hint.  I might use it 
somewhere else.

>> Hashed addresses are useless in hexdumps unless you're comparing
>> with other hashed addresses, which is unlikely.  However, there's
>> no need to break existing code, so introduce a new prefix type
>> that prints unhashed addresses.
> 
> Any user of this? (For the record, I don't see any other mail except this one)

It's patch #2 of this set.  They were all sent together.

http://lkml.iu.edu/hypermail/linux/kernel/2101.2/00245.html

Let me know what you think.

>>          DUMP_PREFIX_NONE,
>>          DUMP_PREFIX_ADDRESS,
>> -       DUMP_PREFIX_OFFSET
>> +       DUMP_PREFIX_OFFSET,
>> +       DUMP_PREFIX_UNHASHED,
> 
> Since it's an address, I would like to group them together, i.e. put
> after DUMP_PREFIX_ADDRESS.

I didn't want to change the numbering of any existing enums, just in 
case there are users that accidentally hard-code the values.  I'm trying 
to make this patch as unobtrusive as possible.

 > Perhaps even add _ADDRESS to DUMP_PREFIX_UNHASHED, but this maybe too 
long.

I think DUMP_PREFIX_ADDRESS_UNHASHED is too long.

>> + * @prefix_type: controls whether prefix of an offset, hashed address,
>> + *  unhashed address, or none is printed (%DUMP_PREFIX_OFFSET,
>> + *  %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_UNHASHED, %DUMP_PREFIX_NONE)
> 
> Yeah, exactly, here you use different ordering.

That's because it's a comment.

>> + * @prefix_type: controls whether prefix of an offset, hashed address,
>> + *  unhashed address, or none is printed (%DUMP_PREFIX_OFFSET,
>> + *  %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_UNHASHED, %DUMP_PREFIX_NONE)
> 
> In both cases I would rather use colon and list one per line. What do you think?

Hmmmm.... if I'm going to change the patch anyway, sure.

>> +               case DUMP_PREFIX_UNHASHED:
> 
> Here is a third type of ordering, can you please be consistent?
> 
>>                  case DUMP_PREFIX_ADDRESS:

Fair enough.