From: Christoph Hellwig <hch@lst.de>
To: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>,
Johannes Thumshirn <jthumshirn@suse.de>,
Jens Axboe <axboe@fb.com>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
dm-devel@redhat.com
Subject: Re: [PATCH 14/15] block/bsg: move queue creation into bsg_setup_queue
Date: Thu, 12 Jan 2017 08:57:54 +0100 [thread overview]
Message-ID: <20170112075754.GB7567@lst.de> (raw)
In-Reply-To: <20170111220122.GA19051@redhat.com>
On Wed, Jan 11, 2017 at 05:01:22PM -0500, Mike Snitzer wrote:
> But I've seen you reference the need to stop multipath from allocating
> its own requests. Are you referring to old request_fn request-based
> multipath's clone_old_rq:alloc_old_clone_request?
Yes, that one is the issue. It allocates a struct request "blind",
that is without known what queue it goes to. With this queue (or blk-mq
for that matter) we need to know the queue, because the request structures
might have additional data behind it and require additional initialization
for drivers that require per-request data. We make use of the per-request
data for SCSI passthrough in this patch.
> Or how blk-mq request-based multipath gets a request from the blk-mq tag
> space (via blk_mq_alloc_request)?
That's fine because it works on the queue of the device that I/O is
submitted to.
next prev parent reply other threads:[~2017-01-12 7:57 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-10 15:06 RFC: split scsi passthrough fields out of struct request Christoph Hellwig
2017-01-10 15:06 ` [PATCH 01/15] virtio_blk: avoid DMA to stack for the sense buffer Christoph Hellwig
2017-01-11 8:26 ` Johannes Thumshirn
2017-01-11 8:26 ` Johannes Thumshirn
2017-01-11 8:43 ` Christoph Hellwig
2017-01-10 15:06 ` [PATCH 02/15] nvme-rdma: fix nvme_rdma_queue_is_ready Christoph Hellwig
2017-01-10 15:06 ` [PATCH 03/15] block: simplify blk_init_allocated_queue Christoph Hellwig
2017-01-10 15:06 ` [PATCH 04/15] block: allow specifying size for extra command data Christoph Hellwig
2017-01-10 15:06 ` [PATCH 05/15] dm: remove incomple BLOCK_PC support Christoph Hellwig
2017-01-12 1:09 ` Mike Snitzer
2017-01-12 8:00 ` Christoph Hellwig
2017-01-12 22:28 ` Mike Snitzer
2017-01-13 8:14 ` Christoph Hellwig
2017-01-13 8:14 ` Christoph Hellwig
2017-01-10 15:06 ` [PATCH 06/15] scsi_dh_rdac: switch to scsi_execute_req_flags() Christoph Hellwig
2017-01-10 15:06 ` [PATCH 07/15] scsi_dh_emc: " Christoph Hellwig
2017-01-10 15:06 ` [PATCH 08/15] scsi_dh_hp_sw: " Christoph Hellwig
2017-01-10 15:06 ` [PATCH 09/15] scsi: remove gfp_flags member in scsi_host_cmd_pool Christoph Hellwig
2017-01-10 15:06 ` [PATCH 10/15] scsi: respect unchecked_isa_dma for blk-mq Christoph Hellwig
2017-01-10 15:06 ` [PATCH 11/15] scsi: remove scsi_cmd_dma_pool Christoph Hellwig
2017-01-10 15:06 ` [PATCH 12/15] scsi: remove __scsi_alloc_queue Christoph Hellwig
2017-01-10 15:06 ` [PATCH 13/15] scsi: allocate scsi_cmnd structures as part of struct request Christoph Hellwig
2017-01-10 15:06 ` [PATCH 14/15] block/bsg: move queue creation into bsg_setup_queue Christoph Hellwig
2017-01-11 8:42 ` Johannes Thumshirn
2017-01-11 8:42 ` Johannes Thumshirn
2017-01-11 8:45 ` Christoph Hellwig
2017-01-11 8:56 ` Johannes Thumshirn
2017-01-11 8:56 ` Johannes Thumshirn
2017-01-11 8:59 ` Christoph Hellwig
2017-01-11 8:59 ` Hannes Reinecke
2017-01-11 8:59 ` Hannes Reinecke
2017-01-11 9:01 ` Christoph Hellwig
2017-01-11 9:37 ` Hannes Reinecke
2017-01-11 9:37 ` Hannes Reinecke
2017-01-11 22:08 ` Mike Snitzer
2017-01-11 22:01 ` Mike Snitzer
2017-01-12 7:57 ` Christoph Hellwig [this message]
2017-01-10 15:06 ` [PATCH 15/15] block: split scsi_request out of struct request Christoph Hellwig
2017-01-12 3:59 ` Jens Axboe
2017-01-12 3:59 ` Jens Axboe
2017-01-11 22:41 ` RFC: split scsi passthrough fields " Mike Snitzer
2017-01-12 7:59 ` Christoph Hellwig
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=20170112075754.GB7567@lst.de \
--to=hch@lst.de \
--cc=axboe@fb.com \
--cc=dm-devel@redhat.com \
--cc=jthumshirn@suse.de \
--cc=linux-block@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=snitzer@redhat.com \
/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.