From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-scsi@vger.kernel.org, Robert Elliott <elliott@hp.com>,
Hannes Reinecke <hare@suse.de>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Bart van Assche <bvanassche@acm.org>, Jens Axboe <axboe@fb.com>,
Kashyap Desai <kashyap.desai@avagotech.com>,
Sreekanth Reddy <sreekanth.reddy@avagotech.com>,
Mike Christie <michaelc@cs.wisc.edu>,
Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
usb-storage@lists.one-eyed-alien.net
Subject: Re: tag handling refactor V2
Date: Wed, 12 Nov 2014 17:15:38 -0800 [thread overview]
Message-ID: <1415841338.7154.33.camel@jarvis.lan> (raw)
In-Reply-To: <1415634990-3023-1-git-send-email-hch@lst.de>
On Mon, 2014-11-10 at 16:56 +0100, Christoph Hellwig wrote:
> - for those drivers looking at the command tagged information we'd need
> to quiesce the LUN. No driver but the 53c700 driver does that, and the
> 53c700 does it at a target-level, which despite a comment claiming it's
> needed doesn't seem to make sense given the code.
I can answer that from ancient memory. The mid-layer tag tracking
wasn't sufficient to track the negotiated state of the tags. the 53c700
was constructed before the slave alloc/configure routines came along, so
it used a per target tracker for the tag negotiation (i.e. it was all on
or all off per target). The reason for the quiesce is so as not to have
to try to work out if any LUN has any tagged commands outstanding when
changing to untagged.
James
prev parent reply other threads:[~2014-11-13 1:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-10 15:56 tag handling refactor V2 Christoph Hellwig
2014-11-10 15:56 ` [PATCH 01/11] scsi: provide a generic change_queue_type method Christoph Hellwig
2014-11-10 15:56 ` [PATCH 02/11] scsi: add new scsi-command flag for tagged commands Christoph Hellwig
2014-11-10 15:56 ` [PATCH 03/11] scsi: remove ordered_tags scsi_device field Christoph Hellwig
2014-11-11 15:37 ` Hannes Reinecke
2014-11-10 15:56 ` [PATCH 04/11] scsi: remove ordered_tag host template field Christoph Hellwig
2014-11-10 15:56 ` [PATCH 05/11] scsi: remove abuses of scsi_populate_tag Christoph Hellwig
2014-11-11 15:39 ` Hannes Reinecke
2014-11-10 15:56 ` [PATCH 06/11] mptfusion: don't change queue type in ->change_queue_depth Christoph Hellwig
2014-11-10 15:56 ` [PATCH 07/11] scsi: remove use_blk_tcq Scsi_Host field Christoph Hellwig
2014-11-10 15:56 ` [PATCH 08/11] scsi: always assign block layer tags if enabled Christoph Hellwig
2014-11-10 15:56 ` [PATCH 09/11] scsi: don't set tagging state from scsi_adjust_queue_depth Christoph Hellwig
2014-11-11 15:41 ` Hannes Reinecke
2014-11-10 15:56 ` [PATCH 10/11] scsi: don't force tagged_supported in drivers Christoph Hellwig
2014-11-11 15:42 ` Hannes Reinecke
2014-11-10 15:56 ` [PATCH 11/11] ufs: remove spurious scsi_set_tag_type call Christoph Hellwig
2014-11-11 15:42 ` Hannes Reinecke
2014-11-10 18:06 ` tag handling refactor V2 Mike Christie
2014-11-10 22:28 ` Jens Axboe
2014-11-12 17:41 ` making the queue_type attribute read only, was: " Christoph Hellwig
2014-11-13 0:33 ` Elliott, Robert (Server Storage)
2014-11-13 11:28 ` Christoph Hellwig
2014-11-13 1:15 ` James Bottomley [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1415841338.7154.33.camel@jarvis.lan \
--to=james.bottomley@hansenpartnership.com \
--cc=axboe@fb.com \
--cc=bvanassche@acm.org \
--cc=elliott@hp.com \
--cc=g.liakhovetski@gmx.de \
--cc=hare@suse.de \
--cc=hch@lst.de \
--cc=kashyap.desai@avagotech.com \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=michaelc@cs.wisc.edu \
--cc=sreekanth.reddy@avagotech.com \
--cc=usb-storage@lists.one-eyed-alien.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.