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From: Christoph Hellwig <hch@infradead.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@infradead.org>,
	"Elliott, Robert (Server Storage)" <Elliott@hp.com>,
	"James Bottomley (jbottomley@parallels.com)"
	<jbottomley@parallels.com>,
	"dgilbert@interlog.com" <dgilbert@interlog.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"Don Brace (PMC)" <Don.Brace@pmcs.com>,
	"Scales, Webb" <webb.scales@hp.com>
Subject: Re: Concurrent SG_SCSI_RESET ioctls
Date: Mon, 13 Oct 2014 03:23:39 -0700	[thread overview]
Message-ID: <20141013102339.GA8765@infradead.org> (raw)
In-Reply-To: <543B9827.2060305@acm.org>

On Mon, Oct 13, 2014 at 11:15:19AM +0200, Bart Van Assche wrote:
> At least to me patches 1/4..3/4 look like nice cleanup patches. Regarding
> patch 4/4: I'm not sure yet what's the best way for addressing potentially
> concurrent SG_SCSI_RESET ioctl calls. As far as I know many SCSI LLDs have
> been implemented assuming that eh_*_reset_handler() calls are serialized per
> SCSI host. Does this mean that a mutex has to be added to avoid that an
> eh_*_reset_handler() call can be triggered via an ioctl while at the same
> time the SCSI error handler thread is invoking one of the
> eh_*_reset_handler() callback functions due to SCSI error handling ?

Both the existing code and my new code still serialize
eh_*_reset_handler callers using the crude tmf_in_progress flag. Using
a proper lock for it would seem preferable to me, as would be bouncing
the work for SG_SCSI_RESET to the EH thread.


      reply	other threads:[~2014-10-13 10:23 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-10 23:32 Concurrent SG_SCSI_RESET ioctls Elliott, Robert (Server Storage)
2014-10-11 11:05 ` Christoph Hellwig
2014-10-11 16:11 ` Christoph Hellwig
2014-10-11 22:06   ` Elliott, Robert (Server Storage)
2014-10-14 11:13     ` Christoph Hellwig
2014-10-14 16:42       ` Douglas Gilbert
2014-10-15 13:25         ` Christoph Hellwig
2014-10-15 14:34           ` Elliott, Robert (Server Storage)
2014-10-24 14:51         ` Christoph Hellwig
2014-10-24 16:29           ` Douglas Gilbert
2014-10-11 23:04   ` Elliott, Robert (Server Storage)
2014-10-13  9:15   ` Bart Van Assche
2014-10-13 10:23     ` Christoph Hellwig [this message]

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