From: Matthew Wilcox <willy-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: James Bottomley
<James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
Cc: Sarah Sharp
<sarah.a.sharp-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
Sebastian Andrzej Siewior
<bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
USB Storage List
<usb-storage-ijkIwGHArpdIPJnuZ7Njw4oP9KaGy4wf@public.gmane.org>
Subject: Re: [usb-storage] Re: Make UAS work on HS for devices with and without command tagging support
Date: Mon, 19 Dec 2011 11:12:25 -0500 [thread overview]
Message-ID: <20111219161225.GO14291@linux.intel.com> (raw)
In-Reply-To: <1324072059.10429.27.camel@dabdike>
On Fri, Dec 16, 2011 at 10:47:39PM +0100, James Bottomley wrote:
> Well, no, what you want to do is use a shared tag map at the block
> level. That will manage a joint tag space for N queues without your
> having to partition it arbitrarily. see scsi_host_find_tag() and
> scsi_init_shared_tag_map().
By the way, the same verbiage about tags being shared across LUNs is also
present in the SAS spec (and various other specs last time I looked,
which wasn't recently). We should probably make this the default in
the SCSI core.
I suspect it hasn't bitten us because there are so few multi-LUN devices
out there, and it's only a "May" check, not "Must" check. But Linux is
technically in violation of the SAS spec by sending two commands to the
same target with the same tag.
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next prev parent reply other threads:[~2011-12-19 16:12 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-14 18:47 Make UAS work on HS for devices with and without command tagging support Sebastian Andrzej Siewior
2011-12-14 18:47 ` [PATCH 1/2] usb/uas: fix support on HS (device without command tagging) Sebastian Andrzej Siewior
[not found] ` <1323888472-21035-2-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2011-12-15 11:14 ` Sergei Shtylyov
2011-12-14 18:47 ` [PATCH 2/2] usb/uas: fix support on HS (device with " Sebastian Andrzej Siewior
2011-12-14 22:53 ` Make UAS work on HS for devices with and without command tagging support Sarah Sharp
2011-12-15 8:44 ` Sebastian Andrzej Siewior
[not found] ` <4EE9B375.4020606-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2011-12-15 21:12 ` [usb-storage] " Sarah Sharp
2011-12-16 14:47 ` Sebastian Andrzej Siewior
2011-12-16 20:12 ` Sebastian Andrzej Siewior
2011-12-16 20:31 ` Matthew Wilcox
2011-12-16 20:42 ` Sebastian Andrzej Siewior
2011-12-16 21:36 ` Sarah Sharp
2011-12-16 21:44 ` Alan Stern
2011-12-16 21:47 ` James Bottomley
2011-12-19 16:12 ` Matthew Wilcox [this message]
2011-12-19 17:14 ` James Bottomley
2011-12-19 18:36 ` Matthew Wilcox
2011-12-19 20:27 ` James Bottomley
2011-12-19 20:57 ` Matthew Wilcox
2011-12-19 21:22 ` James Bottomley
2011-12-19 16:14 ` [PATCH] usb/uas: use unique tags for all LUNs Sebastian Andrzej Siewior
2011-12-19 19:39 ` [PATCH] usb/uas: use scsi_host_find_tag() to find command from a tag Sebastian Andrzej Siewior
[not found] ` <20111219193955.GA2060-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2011-12-19 19:50 ` Matthew Wilcox
2011-12-19 20:12 ` Sarah Sharp
2011-12-19 21:01 ` Matthew Wilcox
2011-12-16 20:51 ` [usb-storage] Re: Make UAS work on HS for devices with and without command tagging support Sarah Sharp
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