From: Matthew Wilcox <willy@infradead.org>
To: Nikolay Borisov <nborisov@suse.com>
Cc: NeilBrown <neilb@suse.com>, Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] VFS: close race between getcwd() and d_move()
Date: Thu, 9 Nov 2017 05:08:54 -0800 [thread overview]
Message-ID: <20171109130854.GB1094@bombadil.infradead.org> (raw)
In-Reply-To: <076c5402-b2ff-2d29-2e38-2c0cb69e89b2@suse.com>
On Thu, Nov 09, 2017 at 01:41:24PM +0200, Nikolay Borisov wrote:
> On 9.11.2017 05:22, NeilBrown wrote:
> > @@ -493,12 +496,18 @@ void __d_drop(struct dentry *dentry)
> > } else
> > hlist_bl_lock(b);
> > __hlist_bl_del(&dentry->d_hash);
> > - dentry->d_hash.pprev = NULL;
> > + if (likely(!moving))
> > + dentry->d_hash.pprev = NULL;
>
> nit: isn't a bit more explicit if (unlikely(moving)). I suspect the end
> result is the same, however it's easy to miss the !. It's not a big deal
> but just wondering.
umm ... you just suggested the exact opposite of what the patch is
intended to do. likely()/unlikely() only hint to the compiler the
probabilities of the branch; they don't change the meaning of the
condition.
next prev parent reply other threads:[~2017-11-09 13:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-09 3:22 [PATCH 0/3] Three VFS patch resends NeilBrown
2017-11-09 3:22 ` [PATCH 1/3] VFS: use synchronize_rcu_expedited() in namespace_unlock() NeilBrown
2017-11-09 3:22 ` [PATCH 2/3] Improve fairness when locking the per-superblock s_anon list NeilBrown
2017-11-09 19:52 ` Linus Torvalds
2017-11-09 20:50 ` Al Viro
2017-11-09 23:09 ` NeilBrown
2017-11-09 23:19 ` Al Viro
2017-11-10 0:02 ` Linus Torvalds
2017-11-10 8:50 ` Christoph Hellwig
2017-11-09 3:22 ` [PATCH 3/3] VFS: close race between getcwd() and d_move() NeilBrown
2017-11-09 11:41 ` Nikolay Borisov
2017-11-09 13:08 ` Matthew Wilcox [this message]
2017-11-09 16:02 ` Nikolay Borisov
2017-11-09 20:23 ` Linus Torvalds
2017-11-09 22:14 ` NeilBrown
2017-11-10 1:40 ` Linus Torvalds
2017-11-10 4:45 ` NeilBrown
2017-11-10 19:52 ` Linus Torvalds
2017-11-10 20:53 ` Al Viro
2017-11-21 23:50 ` Al Viro
2017-11-22 1:31 ` NeilBrown
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