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From: Nick Piggin <npiggin@suse.de>
To: David Howells <dhowells@redhat.com>
Cc: paulmck@linux.vnet.ibm.com, corbet@lwn.net,
	linux-kernel@vger.kernel.org, linux-cachefs@redhat.com
Subject: Re: An incorrect assumption over radix_tree_tag_get()
Date: Wed, 7 Apr 2010 03:09:03 +1000	[thread overview]
Message-ID: <20100406170903.GH5288@laptop> (raw)
In-Reply-To: <23428.1270570789@redhat.com>

On Tue, Apr 06, 2010 at 05:19:49PM +0100, David Howells wrote:
> 
> Hi,
> 
> I think I've made a bad assumption over my usage of radix_tree_tag_get() in
> fs/fscache/page.c.
> 
> I've assumed that radix_tree_tag_get() is protected from radix_tree_tag_set()
> and radix_tree_tag_clear() by the RCU read lock.  However, now I'm not so
> sure.  I think it's only protected against removal of part of the tree.
> 
> Can you confirm?

It is safe. Synchronization requirements for using the radix tree API
are documented.

  reply	other threads:[~2010-04-06 17:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-06 16:19 An incorrect assumption over radix_tree_tag_get() David Howells
2010-04-06 17:09 ` Nick Piggin [this message]
2010-04-06 18:52   ` David Howells
2010-04-06 19:16     ` David Howells
2010-04-06 23:34   ` Dave Chinner
2010-04-07  7:57     ` Nick Piggin

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