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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Christoph Hellwig <hch@lst.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Matthew Wilcox <willy@infradead.org>,
        Kees Cook <keescook@chromium.org>,
        Iurii Zaikin <yzaikin@google.com>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 15/23] seq_file: switch over direct seq_read method calls to seq_read_iter
In-Reply-To: <20200729205919.GB1236929@ZenIV.linux.org.uk>
References: <20200707174801.4162712-1-hch@lst.de> <20200707174801.4162712-16-hch@lst.de> <87eep9rgqu.fsf@nanos.tec.linutronix.de> <20200729205919.GB1236929@ZenIV.linux.org.uk>
Date:   Thu, 30 Jul 2020 09:10:10 +0200
Message-ID: <87eeota371.fsf@nanos.tec.linutronix.de>
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Al Viro <viro@zeniv.linux.org.uk> writes:
> On Fri, Jul 17, 2020 at 11:09:13PM +0200, Thomas Gleixner wrote:
>> 
>> Needs some thought and maybe some cocci help from Julia, but that's way
>> better than this brute force sed thing which results in malformed crap
>> like this:
>> 
>> static const struct file_operations debug_stats_fops = {
>> 	.open		= debug_stats_open,
>> 	.read_iter		= seq_read_iter,
>> 	.llseek		= seq_lseek,
>> 	.release	= single_release,
>> };
>> 
>> and proliferates the copy and paste voodoo programming.
>
> Better copy and paste than templates, IMO; at least the former is
> greppable; fucking DEFINE_..._ATRIBUTE is *NOT*, especially due
> to the use of ##.

Copy and paste itself is not the issue, but once the copy and paste orgy
starts you end up with more subtle bugs and silly differences than
copies. I spent enough time cleaning such crap up just to figure out
that once you've finished a full tree sweep you can start over.

grep for these things is a nuisance, but it's not rocket science to
figure it out. I rather have to figure that out than staring at a
gazillion of broken implementations.

Thanks,

        tglx