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Date:   Sun, 26 Apr 2020 17:26:31 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        hch@infradead.org, david@fromorbit.com,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        linux-xfs@vger.kernel.org
Subject: Re: [RFC PATCH 6/9] iomap: use set/clear_fs_page_private
Message-ID: <20200427002631.GC29705@bombadil.infradead.org>
References: <20200426214925.10970-1-guoqing.jiang@cloud.ionos.com>
 <20200426214925.10970-7-guoqing.jiang@cloud.ionos.com>
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On Sun, Apr 26, 2020 at 11:49:22PM +0200, Guoqing Jiang wrote:
> @@ -59,24 +59,18 @@ iomap_page_create(struct inode *inode, struct page *page)
>  	 * migrate_page_move_mapping() assumes that pages with private data have
>  	 * their count elevated by 1.
>  	 */
> -	get_page(page);
> -	set_page_private(page, (unsigned long)iop);
> -	SetPagePrivate(page);
> -	return iop;
> +	return (struct iomap_page *)set_fs_page_private(page, iop);
>  }

This cast is unnecessary.  void * will be automatically cast to the
appropriate pointer type.

> @@ -556,11 +550,9 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage,
>  
>  	if (page_has_private(page)) {
>  		ClearPagePrivate(page);
> -		get_page(newpage);
> -		set_page_private(newpage, page_private(page));
> +		set_fs_page_private(newpage, (void *)page_private(page));
>  		set_page_private(page, 0);
>  		put_page(page);
> -		SetPagePrivate(newpage);
>  	}

Same comment here as for the btrfs migrate page that Dave reviewed.