Date: Fri, 22 Nov 2002 21:28:46 +0300
From: Yar Tikhiy <yar@freebsd.org>
To: freebsd-scsi@freebsd.org
Subject: {da,sa,...}open bug?
Message-ID: <20021122212846.C60810@comp.chem.msu.su>
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Hi folks,
While debugging the USB mass storage driver, which uses CAM,
I ran into the following doubt.
The XXopen() methods of the da, sa etc drivers get a reference to
the peripheral ("periph") through cam_periph_acquire() and don't
release it on error exit. I suspect this leads to CAM wedge if the
device is removed when its driver is in XXopen(). That is because
the "periph" stays acquired (refcount > 0), but the XXopen() caller
wouldn't invoke XXclose() subsequently since it sees XXopen() having
failed. Thus CAM won't ever "forget" the device removed.
Moreover, after I had patched daopen() to release the peripheral
if returning non-zero error code, the CAM wedge has gone.
I'm new to CAM so I'd like to ask if my idea is correct. Thanks.
--
Yar
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