From: Matthew Wilcox <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Alex Shi <alex.shi@linux.alibaba.com>
Subject: Re: [PATCH] mm: add prototype for __add_to_page_cache_locked()
Date: Wed, 23 Dec 2020 01:19:45 +0000 [thread overview]
Message-ID: <20201223011945.GO874@casper.infradead.org> (raw)
In-Reply-To: <20201222155345.e7086ad37967c9b7feae29e4@linux-foundation.org>
On Tue, Dec 22, 2020 at 03:53:45PM -0800, Andrew Morton wrote:
> : A previous attempt to make this function static led to compilation
> : errors for a few architectures, because __add_to_page_cache_locked() is
> : referred to by BPF code.
Yes, but it's wrong, because it's not architecture dependent. It
depends on CONFIG_DEBUG_INFO_BTF
> > > +/*
> > > + * Any attempt to mark this function as static leads to build failure
> > > + * for few architectures. Adding a prototype to silence gcc warning.
> > > + */
> >
> > We don't need a comment here for this. The commit log is enough.
>
> I think it's OK - people do send patches which remove a prototype and
> also make the function static. A tree-wide grep would catch the bpf
> reference but I suspect people tend to grep for "foo(" rather then
> "foo".
... and the same wrong information is present here. If there's going to
be a comment here at least make it something informative like
/* Must be visible for error injection */
> > > +int __add_to_page_cache_locked(struct page *page, struct address_space *mapping,
> > > + pgoff_t offset, gfp_t gfp, void **shadowp);
> >
> > Please name that 'index', not 'offset'.
>
> I too prefer index over offset.
>
> X1:/usr/src/linux-5.10> grep -r "pgoff_t offset" . | wc -l
> 52
> X1:/usr/src/linux-5.10> grep -r "pgoff_t index" . | wc -l
> 250
>
> But renaming this arg should be a separate patch.
... but this is a new prototype. Prototype names don't have to match
the function name (and often don't ...)
> And I don't think we should be preparing large "rename offset to index"
> patches, please. The value/noise ratio is too low.
I'm only fixing them as I change those functions. I just object to
introducing new wrong ones.
next prev parent reply other threads:[~2020-12-23 1:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 14:19 [PATCH] mm: add prototype for __add_to_page_cache_locked() Souptick Joarder
2020-12-22 20:40 ` Matthew Wilcox
2020-12-22 23:53 ` Andrew Morton
2020-12-23 1:19 ` Matthew Wilcox [this message]
2020-12-23 8:31 ` Christoph Hellwig
2020-12-23 12:11 ` Matthew Wilcox
2020-12-23 15:52 ` Christoph Hellwig
2020-12-28 0:59 ` Alexei Starovoitov
2020-12-23 3:16 Souptick Joarder
2020-12-23 3:18 ` Souptick Joarder
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