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Date: Mon, 16 Dec 2013 00:10:27 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Rui Xiang <rui.xiang@huawei.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] romfs: remove an redundant if condition in
 romfs_readpage
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On Tue, 26 Nov 2013 16:39:09 +0800 Rui Xiang <rui.xiang@huawei.com> wrote:

> Here ret always equals 0, so SetPageUptodate directly.
> 
> ...
>
> --- a/fs/romfs/super.c
> +++ b/fs/romfs/super.c
> @@ -129,8 +129,7 @@ static int romfs_readpage(struct file *file, struct page *page)
>  
>  	if (fillsize < PAGE_SIZE)
>  		memset(buf + fillsize, 0, PAGE_SIZE - fillsize);
> -	if (ret == 0)
> -		SetPageUptodate(page);
> +	SetPageUptodate(page);
>  
>  	flush_dcache_page(page);
>  	kunmap(page);

Nope, `ret' can be -EIO:

	ret = 0;
	if (offset < size) {
		size -= offset;
		fillsize = size > PAGE_SIZE ? PAGE_SIZE : size;

		pos = ROMFS_I(inode)->i_dataoffset + offset;

		ret = romfs_dev_read(inode->i_sb, pos, buf, fillsize);
		if (ret < 0) {
			SetPageError(page);
			fillsize = 0;
-->>			ret = -EIO;
		}
	}

	if (fillsize < PAGE_SIZE)
		memset(buf + fillsize, 0, PAGE_SIZE - fillsize);
	if (ret == 0)
		SetPageUptodate(page);


It was a bit rude to overwrite the romfs_dev_read() return code though.