From: James Bottomley <James.Bottomley@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: dave.jiang@intel.com, linux-scsi@vger.kernel.org,
David Milburn <dmilburn@redhat.com>,
jacek.danecki@intel.com, jack_wang@usish.com,
lindar_liu@usish.com, jeffrey.d.skirvin@intel.com,
edmund.nadolski@intel.com, Srinivas <satyasrinivasp@hcl.in>
Subject: Re: [PATCH] libsas: flush initial device discovery before completing ->scan_finished()
Date: Fri, 18 Feb 2011 18:02:39 -0600 [thread overview]
Message-ID: <1298073759.3007.216.camel@mulgrave.site> (raw)
In-Reply-To: <20110217030633.4303.61603.stgit@localhost6.localdomain6>
On Wed, 2011-02-16 at 19:06 -0800, Dan Williams wrote:
> During initial scan libsas drivers start their phys and notify libsas
> with PORTE_BYTES_DMAED events as port links are established. This
> notification in turn causes libsas to post DISCE_DISCOVER_DOMAIN events
> to the queue. Calling scsi_flush_work() at the end of scan_finished
> guarantees that all preceding PORTE_BYTES_DMAED events have been
> registered in the queue, but it does not guarantee that the resulting
> DISCE_DISCOVER_DOMAIN events have been processed because
> flush_workqueue() explicitly avoids live-locking with incoming work.
>
> Introduce sas_flush_discovery() to guarantee that all initial discovery
> events have completed. It is called after the driver determines all
> initial PORTE_BYTES_DMAED events have had a chance to enter the queue.
> This does not cover BCNs that are generated during expander bring up,
> only the initial sas_discover_domain() event.
I think this is a workaround for an old bug in workqueue flushing (the
flush doesn't clean work it causes) ... I thought that's been fixed for
ages (well, months at least) ... have you verified that this is still a
problem?
James
next prev parent reply other threads:[~2011-02-19 0:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-17 3:06 [PATCH] libsas: flush initial device discovery before completing ->scan_finished() Dan Williams
2011-02-19 0:02 ` James Bottomley [this message]
2011-02-19 1:32 ` Dan Williams
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