From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Waiman Long <Waiman.Long@hp.com>,
Jeff Layton <jlayton@redhat.com>,
Miklos Szeredi <mszeredi@suse.cz>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Andi Kleen <andi@firstfloor.org>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
"Norton, Scott J" <scott.norton@hp.com>
Subject: Re: [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount
Date: Mon, 9 Sep 2013 01:30:26 +0100 [thread overview]
Message-ID: <20130909003026.GI13318@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20130909000300.GH13318@ZenIV.linux.org.uk>
On Mon, Sep 09, 2013 at 01:03:00AM +0100, Al Viro wrote:
> Well... unlazy_walk() is always followed by terminate_walk() very shortly,
> but there's a minor problem - terminate_walk() uses "are we in RCU
> mode?" for two things:
> a) do we need to do path_put() here?
> b) do we need to unlock?
> If you introduce the third case ("no need to do unlock and no need to
> do path_put()"), we'd better decide how to check for that case...
>
> I suspect that minimal variant would be along the lines of
> * have unlazy_walk() slap NULL into ->path.mnt on error, clear
> LOOKUP_RCU and unlock
> * have terminate_walk() check ->path.mnt before doing path_put()
> in !RCU case
> * in do_last() replace bool got_write with struct vfsmount *got_write,
> storing the reference to vfsmount we'd fed to mnt_want_write().
> And use its value when we call mnt_put_write() in there...
>
> I'll put together a commit like that on top of what I was going to push
> into public queues tonight; give me about half an hour, OK?
See the last commit in vfs.git#for-next (38373e1).
next prev parent reply other threads:[~2013-09-09 0:30 UTC|newest]
Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 3:12 [PATCH v7 0/4] Lockless update of reference count protected by spinlock Waiman Long
2013-08-06 3:12 ` [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount Waiman Long
2013-08-29 1:40 ` Linus Torvalds
2013-08-29 4:44 ` Benjamin Herrenschmidt
2013-08-29 7:00 ` Ingo Molnar
2013-08-29 16:43 ` Linus Torvalds
2013-08-29 19:25 ` Linus Torvalds
2013-08-29 23:42 ` Linus Torvalds
2013-08-30 0:26 ` Benjamin Herrenschmidt
2013-08-30 0:49 ` Linus Torvalds
2013-08-30 2:06 ` Michael Neuling
2013-08-30 2:30 ` Benjamin Herrenschmidt
2013-08-30 2:35 ` Linus Torvalds
2013-08-30 2:45 ` Benjamin Herrenschmidt
2013-08-30 2:31 ` Linus Torvalds
2013-08-30 2:43 ` Benjamin Herrenschmidt
2013-08-30 7:16 ` Ingo Molnar
2013-08-30 15:28 ` Linus Torvalds
2013-08-30 3:12 ` Waiman Long
2013-08-30 3:54 ` Linus Torvalds
2013-08-30 7:55 ` Sedat Dilek
2013-08-30 8:10 ` Sedat Dilek
2013-08-30 9:27 ` Sedat Dilek
2013-08-30 9:48 ` Ingo Molnar
2013-08-30 9:56 ` Sedat Dilek
2013-08-30 9:58 ` Sedat Dilek
2013-08-30 10:29 ` Sedat Dilek
2013-08-30 10:36 ` Peter Zijlstra
2013-08-30 10:44 ` Sedat Dilek
2013-08-30 10:46 ` Sedat Dilek
2013-08-30 10:52 ` Peter Zijlstra
2013-08-30 10:57 ` Sedat Dilek
2013-08-30 14:05 ` Sedat Dilek
2013-08-30 11:19 ` Sedat Dilek
2013-08-30 10:38 ` Sedat Dilek
2013-08-30 15:34 ` Linus Torvalds
2013-08-30 15:38 ` Sedat Dilek
2013-08-30 16:12 ` Steven Rostedt
2013-08-30 16:16 ` Sedat Dilek
2013-08-30 18:42 ` Linus Torvalds
2013-08-30 16:32 ` Linus Torvalds
2013-08-30 16:37 ` Sedat Dilek
2013-08-30 16:52 ` Linus Torvalds
2013-08-30 17:11 ` Sedat Dilek
2013-08-30 17:26 ` Linus Torvalds
2013-09-01 10:01 ` Sedat Dilek
2013-09-01 10:33 ` Sedat Dilek
2013-09-01 15:32 ` Linus Torvalds
2013-09-01 15:45 ` Sedat Dilek
2013-09-01 15:55 ` Linus Torvalds
2013-09-02 10:30 ` Sedat Dilek
2013-09-02 16:09 ` David Ahern
2013-09-02 16:09 ` David Ahern
2013-09-01 20:59 ` Linus Torvalds
2013-09-01 21:23 ` Al Viro
2013-09-01 22:16 ` Linus Torvalds
2013-09-01 22:35 ` Al Viro
2013-09-01 22:44 ` Al Viro
2013-09-01 22:58 ` Linus Torvalds
2013-09-01 22:48 ` Linus Torvalds
2013-09-01 23:30 ` Al Viro
2013-09-02 0:12 ` Linus Torvalds
2013-09-02 0:50 ` Linus Torvalds
2013-09-02 0:50 ` Linus Torvalds
2013-09-02 7:05 ` Ingo Molnar
2013-09-02 16:44 ` Linus Torvalds
2013-09-03 10:15 ` Ingo Molnar
2013-09-03 15:41 ` Linus Torvalds
2013-09-03 18:34 ` Linus Torvalds
2013-09-03 19:19 ` Ingo Molnar
2013-09-03 21:05 ` Linus Torvalds
2013-09-03 21:13 ` Linus Torvalds
2013-09-03 21:34 ` Linus Torvalds
2013-09-03 21:39 ` Linus Torvalds
2013-09-03 14:08 ` Pavel Machek
2013-09-03 22:37 ` Sedat Dilek
2013-09-03 22:55 ` Dave Jones
2013-09-03 23:05 ` Sedat Dilek
2013-09-03 23:15 ` Dave Jones
2013-09-03 23:20 ` Sedat Dilek
2013-09-03 23:45 ` Sedat Dilek
2013-08-30 18:33 ` Waiman Long
2013-08-30 18:53 ` Linus Torvalds
2013-08-30 19:20 ` Waiman Long
2013-08-30 19:33 ` Linus Torvalds
2013-08-30 20:15 ` Waiman Long
2013-08-30 20:43 ` Linus Torvalds
2013-08-30 20:54 ` Al Viro
2013-08-30 21:03 ` Linus Torvalds
2013-08-30 21:44 ` Al Viro
2013-08-30 22:30 ` Linus Torvalds
2013-08-31 21:23 ` Al Viro
2013-08-31 22:49 ` Linus Torvalds
2013-08-31 23:27 ` Al Viro
2013-09-01 0:13 ` Al Viro
2013-09-01 17:48 ` Al Viro
2013-09-09 8:30 ` Peter Zijlstra
2013-08-30 21:10 ` Waiman Long
2013-08-30 21:22 ` Linus Torvalds
2013-08-30 21:30 ` Al Viro
2013-08-30 21:42 ` Waiman Long
2013-08-30 19:40 ` Al Viro
2013-08-30 19:52 ` Waiman Long
2013-08-30 20:26 ` Al Viro
2013-08-30 20:35 ` Waiman Long
2013-08-30 20:48 ` Al Viro
2013-08-31 2:02 ` Waiman Long
2013-08-31 2:35 ` Al Viro
2013-08-31 2:42 ` Al Viro
2013-09-02 19:25 ` Waiman Long
2013-09-03 6:01 ` Ingo Molnar
2013-09-03 7:24 ` Sedat Dilek
2013-09-03 15:38 ` Linus Torvalds
2013-09-03 15:14 ` Waiman Long
2013-09-03 15:34 ` Linus Torvalds
2013-09-03 19:09 ` Linus Torvalds
2013-09-03 21:01 ` Waiman Long
2013-09-04 14:52 ` Waiman Long
2013-09-04 15:14 ` Linus Torvalds
2013-09-04 19:25 ` Waiman Long
2013-09-04 21:34 ` Linus Torvalds
2013-09-05 2:35 ` Waiman Long
2013-09-05 13:31 ` Ingo Molnar
2013-09-05 17:33 ` Waiman Long
2013-09-05 17:40 ` Ingo Molnar
2013-09-03 22:41 ` Sedat Dilek
2013-09-03 23:11 ` Sedat Dilek
2013-09-03 23:11 ` Sedat Dilek
2013-09-08 21:45 ` Linus Torvalds
2013-09-09 0:03 ` Al Viro
2013-09-09 0:25 ` Linus Torvalds
2013-09-09 0:35 ` Al Viro
2013-09-09 0:38 ` Linus Torvalds
2013-09-09 0:57 ` Al Viro
2013-09-09 2:09 ` Ramkumar Ramachandra
2013-09-09 0:30 ` Al Viro [this message]
2013-09-09 3:32 ` Linus Torvalds
2013-09-09 4:06 ` Ramkumar Ramachandra
2013-09-09 5:44 ` Al Viro
2013-08-30 17:17 ` Peter Zijlstra
2013-08-30 17:28 ` Linus Torvalds
2013-08-30 17:33 ` Linus Torvalds
2013-08-29 15:20 ` Waiman Long
2013-08-06 3:12 ` [PATCH v7 2/4] spinlock: Enable x86 architecture to do lockless refcount update Waiman Long
2013-08-06 3:12 ` [PATCH v7 3/4] dcache: replace d_lock/d_count by d_lockcnt Waiman Long
2013-08-06 3:12 ` [PATCH v7 4/4] dcache: Enable lockless update of dentry's refcount Waiman Long
2013-08-13 18:03 ` [PATCH v7 0/4] Lockless update of reference count protected by spinlock Waiman Long
-- strict thread matches above, loose matches on Subject: below --
2013-08-31 3:06 [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount George Spelvin
2013-08-31 17:16 ` Linus Torvalds
2013-09-01 8:50 ` George Spelvin
2013-09-01 11:10 ` Theodore Ts'o
2013-09-01 15:49 ` Linus Torvalds
2013-09-01 18:11 ` Steven Rostedt
2013-09-01 20:03 ` Linus Torvalds
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