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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <20210715033704.692967-80-willy@infradead.org>
References: <20210715033704.692967-80-willy@infradead.org> <20210715033704.692967-1-willy@infradead.org>
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc:     dhowells@redhat.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v14 079/138] mm/filemap: Add readahead_folio()
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Date:   Wed, 11 Aug 2021 13:30:15 +0100
Message-ID: <2384708.1628685015@warthog.procyon.org.uk>
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Matthew Wilcox (Oracle) <willy@infradead.org> wrote:

> +/**
> + * readahead_folio - Get the next folio to read.
> + * @ractl: The current readahead request.
> + *
> + * Context: The folio is locked.  The caller should unlock the folio on=
ce
> + * all I/O to that folio has completed.
> + * Return: A pointer to the next folio, or %NULL if we are done.
> + */
> +static inline struct folio *readahead_folio(struct readahead_control *r=
actl)
> +{
> +	struct folio *folio =3D __readahead_folio(ractl);
>  =

> -	return page;
> +	folio_put(folio);

This will oops if __readahead_folio() returns NULL.

> +	return folio;
>  }