Re: [PATCH][next] bcache: Use struct_size() in kzalloc()

Coly Li
2020-06-19T16:18:12Z

On 2020/6/18 13:42, Joe Perches wrote:
> On Thu, 2020-06-18 at 13:38 +0800, Coly Li wrote:
>> On 2020/6/18 06:27, Gustavo A. R. Silva wrote:
>>> Make use of the struct_size() helper instead of an open-coded version
>>> in order to avoid any potential type mistakes.
> []
>>> diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
> []
>>> - io = kzalloc(sizeof(struct dirty_io) +
>>> - sizeof(struct bio_vec) *
>>> - DIV_ROUND_UP(KEY_SIZE(&w->key),
>>> - PAGE_SECTORS),
>>> + io = kzalloc(struct_size(io, bio.bi_inline_vecs,
>> ^^^^^^^^^^^^^^^^^^
>> I like this :-)
>>
>>> + DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS)),
>>
>> The above line seems too long for 80 characters limitation. Does
>> checkpatch.pl complain for this ?
>
> No. checkpatch has changed:

OK, then this patch is good for me.

>
> From bdc48fa11e46f867ea4d75fa59ee87a7f48be144 Mon Sep 17 00:00:00 2001
> From: Joe Perches <joe@perches.com>
> Date: Fri, 29 May 2020 16:12:21 -0700
> Subject: [PATCH] checkpatch/coding-style: deprecate 80-column warning
>
> Yes, staying withing 80 columns is certainly still _preferred_. But
> it's not the hard limit that the checkpatch warnings imply, and other
> concerns can most certainly dominate.
>
> Increase the default limit to 100 characters. Not because 100
> characters is some hard limit either, but that's certainly a "what are
> you doing" kind of value and less likely to be about the occasional
> slightly longer lines.
>
> Miscellanea:
>
> - to avoid unnecessary whitespace changes in files, checkpatch will no
> longer emit a warning about line length when scanning files unless
> --strict is also used
>
> - Add a bit to coding-style about alignment to open parenthesis
>
> Signed-off-by: Joe Perches <joe@perches.com>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I see. My current monitor may display 4 terminal window with 85
characters width, expending the limit to 100 characters means I probably
have to change my current monitor with a good cause.

Thank you, for such good change.

Coly Li