On Fri, 30 Nov 2012, Andrew Morton wrote:

Date: Fri, 30 Nov 2012 12:13:08 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Lukáš Czerner <redacted>
Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, axboe@kernel.dk,
    jmoyer@redhat.com, Neil Brown [off-list ref]
Subject: Re: [PATCH 1/2 v3] wait: add wait_event_lock_irq() interface

On Fri, 30 Nov 2012 12:36:35 +0100 (CET)
Lukáš Czerner [off-list ref] wrote:

quoted

On Fri, 30 Nov 2012, Andrew Morton wrote:

quoted

Date: Fri, 30 Nov 2012 02:48:42 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Lukas Czerner <redacted>
Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, axboe@kernel.dk,
    jmoyer@redhat.com, Neil Brown [off-list ref],
    David Howells [off-list ref], Ingo Molnar [off-list ref],
    Peter Zijlstra [off-list ref]
Subject: Re: [PATCH 1/2 v3] wait: add wait_event_lock_irq() interface

On Fri, 30 Nov 2012 11:42:40 +0100 Lukas Czerner [off-list ref] wrote:

quoted

New wait_event{_interruptible}_lock_irq{_cmd} macros added. This commit
moves the private wait_event_lock_irq() macro from MD to regular wait
includes, introduces new macro wait_event_lock_irq_cmd() instead of using
the old method with omitting cmd parameter which is ugly and makes a use
of new macros in the MD. It also introduces the _interruptible_ variant.

The use of new interface is when one have a special lock to protect data
structures used in the condition, or one also needs to invoke "cmd"
before putting it to sleep.

All new macros are expected to be called with the lock taken. The lock
is released before sleep and is reacquired afterwards. We will leave the
macro with the lock held.

Note to DM: IMO this should also fix theoretical race on waitqueue while
using simultaneously wait_event_lock_irq() and wait_event() because of
lack of locking around current state setting and wait queue removal.

Does this fix the sparse warning which Fengguang just sent us?

Which report from Fengguang do you have in mind ? I do not see any
on linux-kernel today.

/me going to see what spare reports

On Fri, 30 Nov 2012 16:30:24 +0800
kbuild test robot [off-list ref] wrote:

quoted

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm
head:   cfb65dadcd079ad4547407a1584bc6b96bd48bb3
commit: 2b29cdb6f98c86a1da4ec5335d6247392b7c6551 [35/476] wait: add wait_event_lock_irq() interface


sparse warnings:

+ drivers/block/drbd/drbd_int.h:2339:9: sparse: preprocessor token __wait_event_lock_irq redefined
include/linux/wait.h:554:9: this was the original definition
+ drivers/block/drbd/drbd_int.h:2358:9: sparse: preprocessor token wait_event_lock_irq redefined
include/linux/wait.h:621:9: this was the original definition
drivers/block/drbd/drbd_interval.h:12:63: sparse: dubious one-bit signed bitfield
drivers/block/drbd/drbd_interval.h:13:22: sparse: dubious one-bit signed bitfield
drivers/block/drbd/drbd_int.h:903:39: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1123:69: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1124:70: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1125:59: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1126:63: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1127:60: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1128:71: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1129:65: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1130:66: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1335:74: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1336:50: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1338:51: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1339:58: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1340:54: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1341:62: sparse: attribute 'require_context': unknown attribute
drivers/block/drbd/drbd_int.h:1435:92: sparse: attribute 'require_context': unknown attribute

I believe that Lars send patch for that already. So no,

'[PATCH 1/2 v3] wait: add wait_event_lock_irq() interface'

does not fix the issue, but another patch should.

http://www.spinics.net/lists/linux-next/msg23042.html

Thanks!
-Lukas