From: Thomas Gleixner <tglx@linutronix.de>
To: "Sell, Timothy C" <Timothy.Sell@unisys.com>
Cc: "corbet@lwn.net" <corbet@lwn.net>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"Arfvidson, Erik" <Erik.Arfvidson@unisys.com>,
"hofrat@osadl.org" <hofrat@osadl.org>,
"dzickus@redhat.com" <dzickus@redhat.com>,
"jes.sorensen@redhat.com" <jes.sorensen@redhat.com>,
"Curtin, Alexander Paul" <Alexander.Curtin@unisys.com>,
"janani.rvchndrn@gmail.com" <janani.rvchndrn@gmail.com>,
"sudipm.mukherjee@gmail.com" <sudipm.mukherjee@gmail.com>,
"prarit@redhat.com" <prarit@redhat.com>,
"Binder, David Anthony" <David.Binder@unisys.com>,
"nhorman@redhat.com" <nhorman@redhat.com>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"driverdev-devel@linuxdriverproject.org"
<driverdev-devel@linuxdriverproject.org>,
*S-Par-Maintainer <SParMaintainer@unisys.com>,
"Kershner, David A" <David.Kershner@unisys.com>
Subject: RE: [PATCH v4 09/29] staging: unisys: visorinput: remove unnecessary locking
Date: Thu, 9 Jun 2016 21:55:40 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.11.1606092153130.28031@nanos> (raw)
In-Reply-To: <bd6293214ac84ac3a1187911ba6ae69b@US-EXCH13-2.na.uis.unisys.com>
On Thu, 9 Jun 2016, Sell, Timothy C wrote:
> > From: Thomas Gleixner [mailto:tglx@linutronix.de]
> >
> > I think I asked this before, but I might have missed the answer.
> >
> > Why is this a rw_sempahore? It's never taken with down_read and looking
> > at the usage sites it's simply a mutex, right?
>
> If the semaphore --> mutex change would have been as simple as it sounds,
> we would have had NO problem including it with the next version (v3) of this
> patchset. But unfortunately, this change uncovered a latent defect, which
> necessitated yet another patch. (I know... hard to believe that something
> this simple would do that, but it did.) Rather than further complicating this
> patchset, we thought it would be better to address the visorinput issues via a
> separate follow-on patchset.
That makes me curious. What's the issue? Functional is the mutex the same
thing as the r/w semaphore when the latter is only taken down_write and locked
and released by the same thread, which is the case as far as I can tell.
> Is that acceptable for you?
Please fix it before moving the drivers out of staging.
Thanks,
tglx
next prev parent reply other threads:[~2016-06-09 19:57 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-08 21:13 [PATCH v4 00/29] Fixed issues raised by tglx, then move visorbus to drivers/virt David Kershner
2016-06-08 21:13 ` [PATCH v4 01/29] staging: unisys: visorbus: remove return values for write_vbus functions David Kershner
2016-06-08 21:13 ` [PATCH v4 02/29] staging: unisys: visorbus: check parahotplug_request_complete_result David Kershner
2016-06-08 21:13 ` [PATCH v4 03/29] staging: unisys: visorbus: remove unused module parameters David Kershner
2016-06-08 21:13 ` [PATCH v4 04/29] staging: unisys: visorbus: remove unused struct David Kershner
2016-06-08 21:13 ` [PATCH v4 05/29] staging: unisys: visorbus: modify format string to match argument David Kershner
2016-06-08 21:14 ` [PATCH v4 06/29] staging: unisys: visornic: Correct comment spelling mistake David Kershner
2016-06-08 21:14 ` [PATCH v4 07/29] staging: unisys: include: Remove thread-related enum members David Kershner
2016-06-08 21:14 ` [PATCH v4 08/29] staging: unisys: visorbus: removed unused periodic_test_workqueue David Kershner
2016-06-08 21:14 ` [PATCH v4 09/29] staging: unisys: visorinput: remove unnecessary locking David Kershner
2016-06-09 9:01 ` Thomas Gleixner
2016-06-09 12:03 ` Sell, Timothy C
2016-06-09 19:55 ` Thomas Gleixner [this message]
2016-06-09 20:30 ` Sell, Timothy C
2016-06-11 3:34 ` Sell, Timothy C
2016-06-08 21:14 ` [PATCH v4 10/29] staging: unisys: visorbus: use kernel timer instead of workqueue David Kershner
2016-06-08 21:14 ` [PATCH v4 11/29] staging: unisys: visorbus: remove periodic_work.h/.c David Kershner
2016-06-08 21:14 ` [PATCH v4 12/29] staging: unisys: visorbus: Make visordriver_callback_lock a mutex David Kershner
2016-06-08 21:14 ` [PATCH v4 13/29] staging: unisys: visorbus: Remove unnecessary EXPORT_SYMBOL statements David Kershner
2016-06-08 21:14 ` [PATCH v4 14/29] staging: unisys: visorbus: Remove unused functions David Kershner
2016-06-08 21:14 ` [PATCH v4 15/29] staging: unisys: Remove reference to unused STANDALONE_CLIENT David Kershner
2016-06-08 21:14 ` [PATCH v4 16/29] staging: unisys: visorbus: remove unused parameter from function David Kershner
2016-06-08 21:14 ` [PATCH v4 17/29] staging: unisys: visorbus: fix commenting in vbusdevinfo.h David Kershner
2016-06-08 21:14 ` [PATCH v4 18/29] staging: unisys: visorbus: fix commenting in visorbus_main.c David Kershner
2016-06-08 21:14 ` [PATCH v4 19/29] staging: unisys: visorbus: fix visorchannel.c comments David Kershner
2016-06-08 21:14 ` [PATCH v4 20/29] staging: unisys: visorbus: Rectify commenting in visorchipset.c David Kershner
2016-06-08 21:14 ` [PATCH v4 21/29] staging: unisys: visorbus: Move visorbus-unique functions to private header David Kershner
2016-06-08 21:14 ` [PATCH v4 22/29] staging: unisys: visorbus: rectify kerneldoc comment for struct David Kershner
2016-06-08 21:14 ` [PATCH v4 23/29] staging: unisys: visorbus: Remove notifier-related code from visorbus David Kershner
2016-06-08 21:14 ` [PATCH v4 24/29] staging: unisys: visorbus: Rename function to follow existing convention David Kershner
2016-06-08 21:14 ` [PATCH v4 25/29] staging: unisys: visorbus: fix visorbus_private.h comments David Kershner
2016-06-08 21:14 ` [PATCH v4 26/29] staging: unisys: Move vbushelper.h to visorbus directory David Kershner
2016-06-08 21:14 ` [PATCH v4 27/29] include: linux: visorbus: Add visorbus to include/linux directory David Kershner
2016-06-08 21:14 ` [PATCH v4 28/29] Documentation: Move visorbus documentation from staging to Documentation/ David Kershner
2016-06-08 21:14 ` [PATCH v4 29/29] drivers: Add visorbus to the drivers/virt directory David Kershner
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