From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Bottomley <James.Bottomley@HansenPartnership.com>
Subject: Re: [RFC] fix our current target reap infrastructure.
Date: Sun, 15 Dec 2013 19:33:29 -0800
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To: Alan Stern <stern@rowland.harvard.edu>
Cc: Tejun Heo <tj@kernel.org>, Sarah Sharp <sarah.a.sharp@linux.intel.com>, Hans de Goede <hdegoede@redhat.com>, USB list <linux-usb@vger.kernel.org>, SCSI development list <linux-scsi@vger.kernel.org>, USB Storage List <usb-storage@lists.one-eyed-alien.net>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>

On Sun, 2013-12-15 at 21:49 -0500, Alan Stern wrote:
> On Sun, 15 Dec 2013, James Bottomley wrote:
> 
> > No, I was thinking of the two thread scan bug (i.e. two scan threads)
> > not one scan and one remove, which is a bug in the old code.
> 
> By the way, the existing code doesn't allow two threads to scan a
> target at the same time.  They would both have to hold the host's
> scan_mutex.

I thought of that, but it's dropped too early.  That makes the race
almost untriggerable because the racing thread starts way behind, but
it's not theoretically impossible.

> On the other hand, as far as I can see there's nothing to prevent two
> threads from removing a device at the same time.  But that wouldn't 
> cause any problems.

Right.

Thanks,

James