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From: David Howells <dhowells@redhat.com>
To: paulmck@linux.vnet.ibm.com
Cc: dhowells@redhat.com, Eric Dumazet <eric.dumazet@gmail.com>,
	Trond.Myklebust@netapp.com, linux-nfs@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2]
Date: Wed, 31 Mar 2010 18:37:34 +0100	[thread overview]
Message-ID: <15371.1270057054@redhat.com> (raw)
In-Reply-To: <20100331151604.GC2461@linux.vnet.ibm.com>

Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> Protected by something that the caller did, be it holding the the correct
> lock, operating on it during initialization before other CPUs have access
> to it, operating on it during cleanup after other CPUs' access has been
> revoked, or whatever.

But the point I made very early this morning still stands:  What if someone
simply wants to test the pointer, not actually to dereference it?

NFS was using rcu_dereference() for this in a couple of places - which is
overkill.  I suggested stripping this off and you countered with the
suggestion that it should be using rcu_dereference_check().

Why do I need anything at all?

David

  reply	other threads:[~2010-03-31 17:37 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-18 13:33 [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2] David Howells
     [not found] ` <20100318133302.29754.1584.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2010-03-19  2:25   ` Paul E. McKenney
2010-03-19  2:25     ` Paul E. McKenney
2010-03-29 19:02     ` David Howells
2010-03-29 19:21       ` Paul E. McKenney
2010-03-29 20:15         ` David Howells
2010-03-29 20:26           ` Eric Dumazet
2010-03-29 20:26             ` Eric Dumazet
2010-03-29 21:05           ` Paul E. McKenney
2010-03-29 22:22             ` David Howells
2010-03-29 22:36               ` Paul E. McKenney
2010-03-29 22:59                 ` David Howells
2010-03-29 23:26                   ` Paul E. McKenney
2010-03-30 15:40                     ` Paul E. McKenney
2010-03-30 16:39                       ` David Howells
2010-03-30 16:49                         ` Paul E. McKenney
2010-03-30 17:04                           ` Eric Dumazet
2010-03-30 17:04                             ` Eric Dumazet
2010-03-30 17:25                             ` Paul E. McKenney
2010-03-30 17:25                               ` Paul E. McKenney
2010-03-30 23:51                           ` David Howells
2010-03-31  0:08                             ` Paul E. McKenney
2010-03-31 14:04                               ` David Howells
2010-03-31 15:16                                 ` Paul E. McKenney
2010-03-31 17:37                                   ` David Howells [this message]
2010-03-31 18:30                                     ` Paul E. McKenney
2010-03-31 18:32                                     ` Eric Dumazet
2010-03-31 18:32                                       ` Eric Dumazet
2010-03-31 22:53                                       ` David Howells
2010-04-01  1:29                                         ` Paul E. McKenney
2010-04-01 11:45                                           ` David Howells
2010-04-01 14:39                                             ` Paul E. McKenney
2010-04-01 14:46                                               ` David Howells
2010-04-05 17:57                                                 ` Paul E. McKenney
2010-04-06  9:30                                                   ` David Howells
2010-04-06 16:14                                                   ` David Howells
2010-04-06 17:29                                                     ` Paul E. McKenney
2010-04-06 19:34                                                       ` David Howells
2010-04-07  0:02                                                         ` Paul E. McKenney
2010-04-07 13:22                                                           ` David Howells
2010-04-07 15:57                                                             ` Paul E. McKenney
2010-04-07 16:35                                                               ` RCU condition checks David Howells
2010-04-07 17:10                                                                 ` Paul E. McKenney
2010-04-11 22:57                                                                   ` Trond Myklebust
     [not found]                                                                     ` <1271026643.6620.37.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-04-12 16:47                                                                       ` Paul E. McKenney
2010-04-12 16:47                                                                         ` Paul E. McKenney
2010-03-30 16:37                     ` [PATCH] NFS: Fix RCU warnings in nfs_inode_return_delegation_noreclaim() [ver #2] David Howells
2010-03-30 17:01                       ` Paul E. McKenney

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