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From: Arnd Bergmann <arnd@arndb.de>
To: virtualization@lists.linux-foundation.org
Subject: Re: [patch 47/54] Staging: hv: make gVmbusConnection.ChannelLock a real spinlock
Date: Tue, 21 Jul 2009 01:39:19 +0200
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Cc: "Greg Kroah-Hartman" <gregkh@suse.de>, linux-kernel@vger.kernel.org,
       devel@driverdev.osuosl.org, virtualization@lists.osdl.org,
       Sam Ramji <sramji@microsoft.com>,
       Haiyang Zhang <haiyangz@microsoft.com>,
       Hank Janssen <hjanssen@microsoft.com>, shemminger@linux-foundation.org
References: <20090717180850.873962925@mini.kroah.org> <20090717180923.620590305@mini.kroah.org>
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On Friday 17 July 2009, Greg Kroah-Hartman wrote:
> I don't think we really want to be doing a irqsave for this code, but I
> left it alone to preserve the original codepath.  It should be reviewed
> later.

This patch does not preserve the original code path if any of the
callers has a different irq state from the others. When flags is
shared, releasing the lock actually sets the irq state to whatever
another thread was using when failing to acquire the lock while
it was held.

The patch of course looks good, but the comment is misleading.

	Arnd <><