From: David Brownell <david-b@pacbell.net>
To: linux-hotplug@vger.kernel.org
Subject: Re: Update on hot plugging serialization without kernel event queuing
Date: Mon, 12 Mar 2001 19:26:13 +0000 [thread overview]
Message-ID: <marc-linux-hotplug-98442546210130@msgid-missing> (raw)
----- Original Message -----
From: "Adam J. Richter" <adam@yggdrasil.com>
To: <linux-hotplug-devel@lists.sourceforge.net>
Sent: Saturday, February 24, 2001 8:25 PM
Subject: Update on hot plugging serialization without kernel event queuing
> ... deletia ...
>
> Fortunately, there is an approach which would keep the kernel
> and user level code quite simple. You can avoid having race conditions
> and avoid adding event queues in the kernel by following one simple rule:
> once hot plugging is enabled, the mechanism to enable access to a device
> that has been inserted should be activated from user level, not from
> the kernel. This allows the user level agent to acquire a lock
> corresponding to the inserted device _before_ it activates the slot.
That's a good basic strategy that should certainly work. Though "slot"
sounds rather specific to one kind of hardware device ... and at another
level that's what "mount" does for disk-like storage, so I wonder which
subsystems aren't now supporting this strategy. (And PCI seems to
be factored in terms of "function" ... unlike USB right now.)
It'd be good if the "configure through sysadmin tool" cases and hotplug
alert handling used some common "enable now-connected device"
back-end code. It sounds to me like that's what you're suggesting
be created. The "CompactPCI" and "Hotplug PCI" hotplugging
will certainly need a tool to issue their bus-specific ioctls. (I hope the
user interface differs only in use of blue vs red leds!) We know we
need such a facility for PCMCIA ("cardctl").
I'm not sure of how the details would work though. How would
what you're saying affect some of the hotplugging work that's gotten
discussed so far, like SCSI, Cardbus, PCI, PCMCIA, and USB?
- Dave
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
http://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
next reply other threads:[~2001-03-12 19:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-12 19:26 David Brownell [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-02-25 4:25 Update on hot plugging serialization without kernel event queuing Adam J. Richter
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=marc-linux-hotplug-98442546210130@msgid-missing \
--to=david-b@pacbell.net \
--cc=linux-hotplug@vger.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).