Re: [RFC] SAS domain layout for Linux sysfs

From: Christoph Hellwig (hch_at_infradead.org)
Date: 04/25/05

  • Next message: Dmitry Torokhov: "Re: [RFC/PATCH 0/22] W1: sysfs, lifetime and other fixes" 
    Date:	Mon, 25 Apr 2005 17:14:11 +0100
To: Luben Tuikov <luben_tuikov@adaptec.com>

    On Mon, Apr 25, 2005 at 12:06:10PM -0400, Luben Tuikov wrote:
    > On 04/24/05 07:19, Christoph Hellwig wrote:
    > >
    > > This is contrary to any sysfs topology I know about, especially any
    > > existing transport class (SPI, FC, iSCSI).
    >
    > This RFC is about SAS.

    But our SAS transport class should be consistant with the other transport
    classes.

    > > We only ever care about what's seen from a HA,
    >
    > Imagine you could connect to the same device via two
    > different PCI controllers on the same host.

    Which is exactly the case in the examples I've mentioned.

    >
    > > e.g. if you have muliple SPI cards that are
    > > on a single parallel bus you'll have the same bus represented twice,
    > > similarly if you have two fibre channel HBAs connected to the same
    > > SAN you'll have the SAN topology duplicated in both sub-topologies.
    >
    > Hmm, this proposal is for SAS only, Christoph.
    >
    > If you have multiple SAS host adapters connected to the same
    > SAS domain, the _path_ they connect to a SAS device may be _different_.
    > But what is the same is the SAS domain (topology) itself *regardless of
    > how you connect to it.*
    >
    > In order to eliminate duplication of sysfs entries (directories
    > and files) to describe the same SAS device, we split up the
    > representation into a "flat" directory with just a bunch
    > of SAS devices, this is /sys/bus/sas/. And the way you _connect_
    > to those SAS devices is represented in sys/class/sas_ha/.

    Please read the previous mail again, you're not getting it at all.

    If you don't understand the problems it's not worth talking about more.
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  • Next message: Dmitry Torokhov: "Re: [RFC/PATCH 0/22] W1: sysfs, lifetime and other fixes"

    Relevant Pages