linux-kernel - Re: [PATCH 1/4] scsi: Allow hosts to be flagged as hotpluggable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 16 Jul 2009 02:26:42 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	James Bottomley <James.Bottomley@...senPartnership.com>
Cc:	linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
	linux-ide@...r.kernel.org
Subject: Re: [PATCH 1/4] scsi: Allow hosts to be flagged as hotpluggable

On Thu, Jul 16, 2009 at 01:12:28AM +0000, James Bottomley wrote:
> On Thu, 2009-07-16 at 00:43 +0100, Matthew Garrett wrote:
> > Userspace may wish to make policy decisions based on whether a host
> > supports device hotplug or not - for example, AHCI link power management
> > disables hotplug, so may only be desirable on hotplug ports. Add
> > support for marking hosts as hotpluggable in order to allow userspace to
> > treat them appropriately.
> 
> OK, so I don't really understand what the hotplug flag means.
> 
> You seem to be setting it unconditionally on most sata HBAs.  If it just
> means "bus is hotpluggable", it should be set to 1 at initialisation and
> the few non hot plug busses (like SPI) get to reset it.

It's a tossup. PATA's not hotpluggable (in the general case), so I just 
picked a default and went with it. Inverting it would be easy enough, I 
guess.

> However, by definition SATA (like SAS) is a hotplug bus ... why isn't it
> set for some SATA controllers ... is it because the HBA itself does
> something wrong when a hotplug event comes in?

Some older controllers don't provide direct access to the phy registers, 
so there's no way to interpret hotplug events correctly.

-- 
Matthew Garrett | mjg59@...f.ucam.org
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/