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From: Tejun Heo <tj@kernel.org>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: laijs@cn.fujitsu.com, linux-kernel@vger.kernel.org,
	Stefan Richter <stefanr@s5r6.in-berlin.de>,
	linux1394-devel@lists.sourceforge.net,
	Chris Boot <bootc@bootc.net>,
	linux-scsi@vger.kernel.org, target-devel@vger.kernel.org
Subject: Re: [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK
Date: Sat, 22 Feb 2014 09:38:59 -0500	[thread overview]
Message-ID: <20140222143859.GD12830@htj.dyndns.org> (raw)
In-Reply-To: <5307E550.4040004@hurleysoftware.com>

Hey,

On Fri, Feb 21, 2014 at 06:46:24PM -0500, Peter Hurley wrote:
> It's a long story but the short version is that
> Documentation/memory-barriers.txt recently was overhauled to reflect
> what cpus actually do and what the different archs actually
> deliver.
> 
> Turns out that unlock + lock is not guaranteed by all archs to be
> a full barrier. Thus the smb_mb__after_unlock_lock().
> 
> This is now all spelled out in memory-barriers.txt under the
> sub-heading "IMPLICIT KERNEL MEMORY BARRIERS".

So, that one is for unlock/lock sequence, not smp_mb__after_unlock().
Urgh... kinda dislike adding smp_rmb() there as it's one of the
barriers which translate to something weighty on most, if not all,
archs.

Thanks.

-- 
tejun

  reply	other threads:[~2014-02-22 14:39 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-20 20:44 [PATCHSET wq/for-3.15] workqueue: remove PREPARE_[DELAYED_]WORK() Tejun Heo
2014-02-20 20:44 ` [PATCH 1/9] wireless/rt2x00: don't use PREPARE_WORK in rt2800usb.c Tejun Heo
2014-03-07 15:26   ` Tejun Heo
2014-02-20 20:44 ` [PATCH 2/9] ps3-vuart: don't use PREPARE_WORK Tejun Heo
2014-02-21 23:19   ` Geoff Levand
2014-02-20 20:44 ` [PATCH 3/9] floppy: don't use PREPARE_[DELAYED_]WORK Tejun Heo
2014-02-21  9:37   ` Jiri Kosina
2014-02-20 20:44 ` [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK Tejun Heo
2014-02-21  1:44   ` Peter Hurley
2014-02-21  1:59     ` Tejun Heo
2014-02-21  2:07       ` Peter Hurley
2014-02-21  2:13         ` Tejun Heo
2014-02-21  5:13           ` Peter Hurley
2014-02-21 10:03             ` Tejun Heo
2014-02-21 12:51               ` Peter Hurley
2014-02-21 13:06                 ` Tejun Heo
2014-02-21 16:53                   ` Peter Hurley
2014-02-21 16:57                     ` Tejun Heo
2014-02-21 23:01                       ` Peter Hurley
2014-02-21 23:18                         ` Tejun Heo
2014-02-21 23:46                           ` Peter Hurley
2014-02-22 14:38                             ` Tejun Heo [this message]
2014-02-22 14:48                               ` Peter Hurley
2014-02-22 18:43                         ` James Bottomley
2014-02-22 18:48                           ` Peter Hurley
2014-02-22 18:52                             ` James Bottomley
2014-02-22 19:03                               ` Peter Hurley
2014-02-23  1:23                                 ` memory-barriers.txt again (was Re: [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK) Stefan Richter
2014-02-23 16:37                                   ` Paul E. McKenney
2014-02-23 20:35                                     ` Peter Hurley
2014-02-23 23:50                                       ` Paul E. McKenney
2014-02-24  0:09                                         ` Peter Hurley
2014-02-24 16:26                                           ` Paul E. McKenney
2014-02-24  0:32                                         ` Stefan Richter
2014-02-24 16:27                                           ` Paul E. McKenney
2014-02-23 20:05                                 ` [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK James Bottomley
2014-02-23 22:32                                   ` Peter Hurley
2014-02-21 20:45   ` Stefan Richter
2014-03-05 21:34     ` Stefan Richter
2014-03-07 15:18       ` Tejun Heo
2014-03-07 15:26   ` [PATCH UPDATED " Tejun Heo
2014-02-20 20:44 ` [PATCH 5/9] usb: " Tejun Heo
2014-02-20 20:59   ` Greg Kroah-Hartman
2014-02-21 15:06     ` Alan Stern
2014-02-21 15:07       ` Tejun Heo
2014-02-22 14:59   ` [PATCH v2 " Tejun Heo
2014-02-22 15:14     ` Alan Stern
2014-02-22 15:20       ` Peter Hurley
2014-02-22 15:37       ` Tejun Heo
2014-02-22 23:03         ` Alan Stern
2014-02-23  4:29           ` Tejun Heo
2014-02-20 20:44 ` [PATCH 6/9] nvme: don't use PREPARE_WORK Tejun Heo
2014-03-07 15:26   ` Tejun Heo
2014-02-20 20:44 ` [PATCH 7/9] afs: " Tejun Heo
2014-02-20 22:00   ` David Howells
2014-02-20 22:46     ` Tejun Heo
2014-03-07 15:27   ` Tejun Heo
2014-02-20 20:44 ` [PATCH 8/9] staging/fwserial: " Tejun Heo
2014-02-21 15:13   ` Peter Hurley
2014-02-20 20:44 ` [PATCH 9/9] workqueue: remove PREPARE_[DELAYED_]WORK() Tejun Heo
2014-03-07 15:27   ` Tejun Heo

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