From: Lee Revell <rlrevell@joe-job.com>
To: Takao Indoh <indou.takao@soft.fujitsu.com>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4][diskdump] x86-64 support
Date: Sat, 04 Sep 2004 18:31:31 -0400 [thread overview]
Message-ID: <1094337090.6575.474.camel@krustophenia.net> (raw)
In-Reply-To: <9AC48F3A62CFC4indou.takao@soft.fujitsu.com>
On Tue, 2004-08-31 at 05:10, Takao Indoh wrote:
> >As in the scsi code spin_is_locked checks are bogus and racy. Only
> >a spin_trylock would be safe. hd can't be NULL.
>
> Could you explain to me why spin_is_locked is not safe?
>
Say you have a door with a lock, and someone on the other side. You
look at the lock, see that it's unlocked, then open the door. You
cannot guarantee that the door will open because the person on the other
side could have locked it between the time you looked and turned the
handle.
The only way to know for sure whether the door is locked is to turn the
handle and see if it opens.
Lee
prev parent reply other threads:[~2004-09-04 22:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-28 9:43 [PATCH 0/4][diskdump] x86-64 support Takao Indoh
2004-08-28 9:44 ` [PATCH 1/4][diskdump] " Takao Indoh
2004-08-28 9:45 ` [PATCH 2/4][diskdump] " Takao Indoh
2004-08-28 10:21 ` Christoph Hellwig
2004-08-28 9:47 ` [PATCH 3/4][diskdump] " Takao Indoh
2004-08-28 9:48 ` [PATCH 4/4][diskdump] " Takao Indoh
2004-08-28 10:23 ` Christoph Hellwig
2004-08-31 9:10 ` Takao Indoh
2004-09-04 11:11 ` Christoph Hellwig
2004-09-04 22:31 ` Lee Revell [this message]
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