From: Joe Perches <joe@perches.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>, Ian Kent <raven@themaw.net>,
David Howells <dhowells@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
LSM List <linux-security-module@vger.kernel.org>,
NetFilter <netfilter-devel@vger.kernel.org>
Subject: Re: clean up kernel_{read,write} & friends v2
Date: Thu, 28 May 2020 12:22:08 -0700 [thread overview]
Message-ID: <f68b7797aa73452d99508bdaf2801b3d141e7a69.camel@perches.com> (raw)
In-Reply-To: <CAHk-=wj3iGQqjpvc+gf6+C29Jo4COj6OQQFzdY0h5qvYKTdCow@mail.gmail.com>
On Thu, 2020-05-28 at 11:51 -0700, Linus Torvalds wrote:
> On Wed, May 27, 2020 at 10:40 PM Christoph Hellwig <hch@lst.de> wrote:
> > this series fixes a few issues and cleans up the helpers that read from
> > or write to kernel space buffers, and ensures that we don't change the
> > address limit if we are using the ->read_iter and ->write_iter methods
> > that don't need the changed address limit.
>
> Apart from the "please don't mix irrelevant whitespace changes with
> other changes" comment, this looks fine to me.
>
> And a rant related to that change: I'm really inclined to remove the
> checkpatch check for 80 columns entirely, but it shouldn't have been
> triggering for old lines even now.
>
> Or maybe make it check for something more reasonable, like 100 characters.
>
> I find it ironic and annoying how "checkpatch" warns about that silly
> legacy limit, when checkpatch itself then on the very next few lines
> has a line that is 124 columns wide
Yeah. perl ain't c.
And this discussion has been had many times.
Here's one from 2009
https://lkml.org/lkml/2009/12/15/490
Another from 2012
https://lkml.org/lkml/2012/2/5/141
Line lengths checks are normally pretty silly.
Hard limits at 80 really don't work well, especially with
some of the 25+ character length identifiers used today.
I think a line length warning at 132 is generally reasonable
but it could depend on complexity and identifier lengths.
> And yes, that 124 character line has a good reason for it. But that's
> kind of the point. There are lots of perfectly fine reasons for longer
> lines.
>
> I'd much rather check for "no deep indentation" or "no unnecessarily
> complex conditionals" or other issues that are more likely to be
> _real_ problems.
That deep indentation test already exists at 6 tabs.
Maybe it should be 5 instead. Or maybe even 4, but
that's a pretty easy to need and common use case.
Tab depth use in the kernel is more or less
$ git grep -Poh '^\t+(if|do|while|for|switch)\b' | \
sed -r 's/\w+//g' | \
awk '{print length($0);}' | \
sort | uniq -c | sort -rn
903993 1
339059 2
89334 3
18216 4
3282 5
605 6
148 7
36 8
4 9
1 10
> But do we really have 80x25 terminals any more that
> we'd care about?
trivial btw: VT100s were 80x24 or 132x24, PCs were 80x25
next prev parent reply other threads:[~2020-05-28 19:29 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 5:40 clean up kernel_{read,write} & friends v2 Christoph Hellwig
2020-05-28 5:40 ` [PATCH 01/14] cachefiles: switch to kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 02/14] autofs: " Christoph Hellwig
2020-05-28 5:40 ` [PATCH 03/14] bpfilter: " Christoph Hellwig
2020-05-28 5:40 ` [PATCH 04/14] fs: unexport __kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 05/14] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 06/14] fs: remove the call_{read,write}_iter functions Christoph Hellwig
2020-05-28 18:56 ` Al Viro
2020-05-29 5:51 ` Christoph Hellwig
2020-05-28 5:40 ` [PATCH 07/14] fs: implement kernel_write using __kernel_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 08/14] fs: remove __vfs_write Christoph Hellwig
2020-05-28 5:40 ` [PATCH 09/14] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-05-28 18:43 ` Linus Torvalds
2020-05-29 12:32 ` Christoph Hellwig
2020-05-31 23:59 ` Logan Gunthorpe
2020-05-28 19:00 ` Al Viro
2020-05-29 5:57 ` Christoph Hellwig
2020-05-29 13:37 ` Christoph Hellwig
2020-05-28 5:40 ` [PATCH 10/14] fs: add a __kernel_read helper Christoph Hellwig
2020-05-28 5:40 ` [PATCH 11/14] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-05-28 5:40 ` [PATCH 12/14] fs: implement kernel_read " Christoph Hellwig
2020-05-28 5:40 ` [PATCH 13/14] fs: remove __vfs_read Christoph Hellwig
2020-05-28 5:40 ` [PATCH 14/14] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig
2020-05-28 19:03 ` Al Viro
2020-05-28 18:51 ` clean up kernel_{read,write} & friends v2 Linus Torvalds
2020-05-28 18:57 ` Sedat Dilek
2020-05-28 19:22 ` Joe Perches [this message]
2020-05-28 19:33 ` Al Viro
2020-05-28 19:44 ` Matthew Wilcox
2020-05-28 20:06 ` Al Viro
2020-05-28 20:14 ` Deucher, Alexander
2020-05-28 20:18 ` Joe Perches
2020-05-28 20:29 ` Dave Airlie
2020-05-28 21:03 ` Joe Perches
2020-05-28 20:17 ` David Howells
2020-05-28 21:20 ` Casey Schaufler
2020-05-29 13:08 ` David Laight
2020-05-29 19:19 ` Linus Torvalds
2020-05-29 22:02 ` Casey Schaufler
2020-05-29 23:12 ` [PATCH] checkpatch/coding-style: Allow 100 column lines Joe Perches
2020-05-30 22:14 ` Andreas Dilger
2020-05-30 23:15 ` Joe Perches
2020-06-05 6:36 ` clean up kernel_{read,write} & friends v2 Philippe Mathieu-Daudé
2020-06-05 15:00 ` Nicolas Pitre
-- strict thread matches above, loose matches on Subject: below --
2020-05-13 6:56 Christoph Hellwig
2020-05-20 15:59 ` Christoph Hellwig
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