linux-kernel - Re: [PATCH] EXPORTFS: handle NULL returns from fh_to_dentry()/fh_to

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Date:	Tue, 09 Dec 2008 10:30:11 +0000
From:	David Howells <dhowells@...hat.com>
To:	"J. Bruce Fields" <bfields@...ldses.org>
Cc:	dhowells@...hat.com,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>, hugh@...itas.com,
	hch@...radead.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] EXPORTFS: handle NULL returns from fh_to_dentry()/fh_to_parent()

J. Bruce Fields <bfields@...ldses.org> wrote:

> +	if (!result)
> +		result = ERR_PTR(-ESTALE);
>  	if (IS_ERR(result))
>  		return result;

This is why I think this is a bad idea.  This adds an extra conditional test
and branch.  In fact, the way you've done it means you have to do the extra
branch whatever[*]; it might be better to have the if-statement you added
return directly.

[*] assuming gcc doesn't manage to be clever enough to omit the second test if
    the first is true.

David
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