From: Danny Milosavljevic <dannym@scratchpost.org>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: 30629@debbugs.gnu.org
Subject: [bug#30629] Device mapper modalias
Date: Wed, 7 Mar 2018 19:56:25 +0100 [thread overview]
Message-ID: <20180307195625.1708032a@scratchpost.org> (raw)
In-Reply-To: <87r2p46r7k.fsf@gnu.org>
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Hi Ludo,
On Thu, 01 Mar 2018 11:11:11 +0100
ludo@gnu.org (Ludovic Courtès) wrote:
> > assert(tablestatus.header.target_count == 1);
> > printf("target_type %s\n", tablestatus.items[0].target_type); // prints "crypto", hence we should modprobe "dm-crypto".
>
> Is this target_type/module name mapping always correct?
Yes - since that's how Linux itself loads the dm modules:
./drivers/md/dm-target.c: request_module("dm-%s", name);
(and see dm-table.c where once can see that name = target_type of the table structure)
On the other hand, not all dm-*.ko are targets!
> If so, we could always implement this DM_TABLE_STATUS ioctl and use it,
> although if it loads modules as a side effect that’s not great.
> > Alternatively, there's even a dm-uevent.c for sysfs AND we have enabled it AND it's supposed
> > to report DM_TARGET - but I can't see it. Maybe it only does that for events and not for state.
I checked it now - it's only reported for events: it reports which target caused
the event.
It would be easy to extend Linux to also report the targets in the state, but
that won't help us with past kernels - and since our use case is mostly
to get the module list starting from an already-running system, it won't
help us.
So I think the ioctl is the best way.
> > $ udevadm info -q all /dev/dm-0
> >
> > ... which has quite a lot of the info, but not the module name.
>
> Hmm! So how do other distros do? There must be a way to get the module
> name no?
Good question... no idea.
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prev parent reply other threads:[~2018-03-07 18:57 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-27 14:17 [bug#30629] [PATCH 0/5] Detect missing modules in the initrd Ludovic Courtès
2018-02-27 14:22 ` Ludovic Courtès
2018-02-27 14:22 ` [bug#30629] [PATCH 1/5] Add (guix glob) Ludovic Courtès
2018-02-27 21:45 ` Marius Bakke
2018-02-28 11:25 ` Danny Milosavljevic
2018-03-01 9:57 ` Ludovic Courtès
2018-03-01 10:11 ` Danny Milosavljevic
2018-03-01 14:29 ` Danny Milosavljevic
2018-02-27 14:22 ` [bug#30629] [PATCH 2/5] linux-modules: Add 'device-module-aliases' and related procedures Ludovic Courtès
2018-02-27 19:33 ` Danny Milosavljevic
2018-02-27 20:55 ` Ludovic Courtès
2018-02-27 21:58 ` Danny Milosavljevic
2018-02-27 21:24 ` Ludovic Courtès
2018-02-27 14:22 ` [bug#30629] [PATCH 3/5] linux-initrd: Separate file system module logic Ludovic Courtès
2018-03-01 14:31 ` Danny Milosavljevic
2018-02-27 14:22 ` [bug#30629] [PATCH 4/5] system: Add 'initrd-modules' field Ludovic Courtès
2018-03-01 18:39 ` Danny Milosavljevic
2018-02-27 14:22 ` [bug#30629] [PATCH 5/5] guix system: Check for the lack of modules in the initrd Ludovic Courtès
2018-03-02 12:39 ` Danny Milosavljevic
2018-02-27 21:29 ` [bug#30629] [PATCH 0/5] Detect missing " Danny Milosavljevic
2018-02-27 21:15 ` Ludovic Courtès
2018-02-27 22:50 ` Danny Milosavljevic
2018-02-27 23:13 ` [bug#30638] [WIP v2] linux-initrd: Make modprobe pure-Guile Danny Milosavljevic
2018-02-27 23:17 ` Danny Milosavljevic
2018-02-28 11:47 ` [bug#30638] [WIP v3] " Danny Milosavljevic
2018-02-28 12:05 ` [bug#30638] [WIP v4] " Danny Milosavljevic
2018-02-28 11:36 ` [bug#30629] [PATCH 0/5] Detect missing modules in the initrd Danny Milosavljevic
2018-03-01 10:05 ` Ludovic Courtès
2018-03-01 10:11 ` Danny Milosavljevic
2018-03-01 11:46 ` Danny Milosavljevic
2018-03-01 13:39 ` Ludovic Courtès
2018-03-01 13:54 ` Danny Milosavljevic
2018-03-02 12:56 ` bug#30629: " Ludovic Courtès
2018-03-02 17:50 ` [bug#30629] " Danny Milosavljevic
2018-03-02 18:16 ` Danny Milosavljevic
2018-03-03 8:42 ` Ludovic Courtès
2018-03-01 13:55 ` Danny Milosavljevic
2018-03-01 21:20 ` Ludovic Courtès
2018-03-02 11:42 ` Danny Milosavljevic
2018-02-28 3:03 ` [bug#30629] Device mapper modalias Danny Milosavljevic
2018-03-01 8:56 ` Danny Milosavljevic
2018-03-01 10:11 ` Ludovic Courtès
2018-03-07 18:56 ` Danny Milosavljevic [this message]
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