Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753483Ab0KJDhi (ORCPT ); Tue, 9 Nov 2010 22:37:38 -0500 Received: from ozlabs.org ([203.10.76.45]:50895 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752104Ab0KJDhh (ORCPT ); Tue, 9 Nov 2010 22:37:37 -0500 Subject: Re: [RFC][PATCH] perf: sysfs type id From: Michael Ellerman Reply-To: michael@ellerman.id.au To: Kay Sievers Cc: LKML In-Reply-To: References: <1289339119.2191.92.camel@laptop> <20101109221338.GA19947@suse.de> <1289345811.10536.8.camel@concordia> <1289350360.22787.9.camel@concordia> <1289351423.22787.22.camel@concordia> <1289353544.22787.49.camel@concordia> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-gJ1Y9VrJ7vwVEiNBBYm6" Date: Wed, 10 Nov 2010 14:37:33 +1100 Message-ID: <1289360253.22787.51.camel@concordia> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2850 Lines: 78 --=-gJ1Y9VrJ7vwVEiNBBYm6 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2010-11-10 at 02:59 +0100, Kay Sievers wrote: > On Wed, Nov 10, 2010 at 02:45, Michael Ellerman = wrote: > > On Wed, 2010-11-10 at 02:19 +0100, Kay Sievers wrote: > >> On Wed, Nov 10, 2010 at 02:10, Michael Ellerman wrote: > >> > On Wed, 2010-11-10 at 01:57 +0100, Kay Sievers wrote: > >> >> Stay on the list please, with any possible reply. Thanks! > >> > > >> > You dropped the CC when you replied, or is my mailer being weird? > >> > >> You replied to me only: > >> From: Michael Ellerman > >> To: Kay Sievers > > > > Because you replied to me only, or at least that's what I see at my end= . >=20 > Sure, I don't add lists back when people reply to me only. You never > know why they do that, and if they have a reason for it. That's why I > added the the same mail: > "Stay on the list please, with any possible reply. Thanks!" >=20 > >> Devices can never be on two subsystems at the same time. Not with > >> classes, not with buses, that was never, and probably will never be > >> possible. > > > > OK, I guess I'm getting my terminology wrong. My devices, which show up > > in /sys/class/foo are symlinks into /sys/devices/virtual/foo, so they > > _appear_ to be in two places. > > > > I also see entries for example in /sys/class/scsi_disk that link > > into /sys/devices/pci. >=20 > Sure, all devices (devices are real directories) end up in the tree in > /sys/devices/. That's one tree, where all the devices from different > subsystems stack on top of others. >=20 >=20 > All devices have a symlink called 'subsystem' which points back to the > individual class the device belongs to. >=20 > To find all device of a specific subsystem, you start at the subsystem > directory (class/bus) which collects them (only symlinks to the > device, not directories). >=20 > That way you will find a blockdev, even when it's deep down in a chain > of devices: > pci:bridge/pci:dev/scsi:host/scsi:target/scsi:lun/block OK, I think I get it. Thanks for taking the time to explain it to me :) cheers --=-gJ1Y9VrJ7vwVEiNBBYm6 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEABECAAYFAkzaE30ACgkQdSjSd0sB4dKyxQCgpU3tANNcXYiq/NyBxhYux73u TjEAoLtKQdEMvpZWSYSbHwgan2iFPI0l =vlAx -----END PGP SIGNATURE----- --=-gJ1Y9VrJ7vwVEiNBBYm6-- -- 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/