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Date:   Mon, 26 Jun 2023 21:12:07 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc:     linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jan Kara <jack@suse.com>,
        David Howells <dhowells@redhat.com>
Subject: Re: [PATCH 03/12] writeback: Factor should_writeback_folio() out of
 write_cache_pages()
Message-ID: <ZJphl4Ws4QzitTny@infradead.org>
References: <20230626173521.459345-1-willy@infradead.org>
 <20230626173521.459345-4-willy@infradead.org>
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> +	if (folio_test_writeback(folio)) {
> +		if (wbc->sync_mode != WB_SYNC_NONE)
> +			folio_wait_writeback(folio);
> +		else
> +			return false;
> +	}

Please reorder this to avoid the else and return earlier while you're
at it:

	if (folio_test_writeback(folio)) {
		if (wbc->sync_mode == WB_SYNC_NONE)
			return false;
		folio_wait_writeback(folio);
	}

(that's what actually got me started on my little cleanup spree while
checking some details of the writeback waiting..)

> +	BUG_ON(folio_test_writeback(folio));
> +	if (!folio_clear_dirty_for_io(folio))
> +		return false;
> +
> +	return true;

..

	return folio_clear_dirty_for_io(folio);

?