linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Bart Van Assche <bvanassche@acm.org>
To: Christoph Hellwig <hch@infradead.org>,
	Palmer Dabbelt <palmer@dabbelt.com>
Cc: snitzer@redhat.com, josef@toxicpanda.com, corbet@lwn.net,
	kernel-team@android.com, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
	song@kernel.org, dm-devel@redhat.com,
	linux-kselftest@vger.kernel.org, shuah@kernel.org,
	agk@redhat.com, michael.christie@oracle.com
Subject: Re: [PATCH v1 0/5] dm: dm-user: New target that proxies BIOs to userspace
Date: Wed, 23 Dec 2020 08:59:38 -0800	[thread overview]
Message-ID: <8f09b196-0977-3b81-2bfe-4a97b1e0e3aa@acm.org> (raw)
In-Reply-To: <20201223074850.GA15369@infradead.org>

On 12/22/20 11:48 PM, Christoph Hellwig wrote:
> FYI, a few years ago I spent some time helping a customer to prepare
> their block device in userspace using fuse code for upstreaming, but
> at some point they abandoned the project.  But if for some reason we
> don't want to use nbd I think a driver using the fuse infrastructure
> would be the next logical choice.

Hi Christoph,

Thanks for having shared this information. Since I'm not familiar with the
FUSE code: does this mean translating block device accesses into FUSE_READ
and FUSE_WRITE messages? Does the FUSE kernel code only support exchanging
such messages between kernel and user space via the read() and write()
system calls? I'm asking this since there is already an interface in the
Linux kernel for implementing block devices in user space that uses another
approach, namely a ring buffer for messages and data that is shared between
kernel and user space (documented in Documentation/target/tcmu-design.rst).
Is one system call per read and per write operation fast enough for all
block-device-in-user-space implementations?

Thanks,

Bart.

  reply	other threads:[~2020-12-23 17:00 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03 21:58 [PATCH v1 0/5] dm: dm-user: New target that proxies BIOs to userspace Palmer Dabbelt
2020-12-03 21:58 ` [PATCH v1 1/5] Documentation: Describe dm-user Palmer Dabbelt
2020-12-03 21:58 ` [PATCH v1 2/5] uapi: Add dm-user structure definition Palmer Dabbelt
2020-12-03 21:58 ` [PATCH v1 3/5] dm: dm-user: New target that proxies BIOs to userspace Palmer Dabbelt
2020-12-03 21:58 ` [PATCH v1 4/5] selftests/dm-user: A handful of tests for dm-user Palmer Dabbelt
2020-12-03 21:58 ` [PATCH v1 5/5] MAINTAINERS: Add myself as a dm-user maintainer Palmer Dabbelt
2020-12-04 10:33 ` [PATCH v1 0/5] dm: dm-user: New target that proxies BIOs to userspace Christoph Hellwig
2020-12-07 18:55   ` Palmer Dabbelt
2020-12-10  3:38     ` [dm-devel] " Bart Van Assche
2020-12-10 17:03       ` Josef Bacik
2020-12-15  3:00         ` Palmer Dabbelt
2020-12-16 18:24           ` Vitaly Mayatskih
2020-12-17  6:55             ` Palmer Dabbelt
2020-12-22 13:32           ` Christoph Hellwig
2020-12-22 14:36             ` Mike Snitzer
2020-12-22 20:38               ` Palmer Dabbelt
2020-12-23  7:48                 ` Christoph Hellwig
2020-12-23 16:59                   ` Bart Van Assche [this message]
2020-12-22 20:31             ` [dm-devel] " Palmer Dabbelt

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=8f09b196-0977-3b81-2bfe-4a97b1e0e3aa@acm.org \
    --to=bvanassche@acm.org \
    --cc=agk@redhat.com \
    --cc=corbet@lwn.net \
    --cc=dm-devel@redhat.com \
    --cc=hch@infradead.org \
    --cc=josef@toxicpanda.com \
    --cc=kernel-team@android.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-raid@vger.kernel.org \
    --cc=michael.christie@oracle.com \
    --cc=palmer@dabbelt.com \
    --cc=shuah@kernel.org \
    --cc=snitzer@redhat.com \
    --cc=song@kernel.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).