Re: [RFC] fs: add userspace critical mounts event support

From	"Luis R. Rodriguez" <mcgrof@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [RFC] fs: add userspace critical mounts event support
Date	2016-10-05 02:30 +0200
Message-ID	<soIfT-1zP-13@gated-at.bofh.it> (permalink)
References	(7 earlier) <sdnHP-h4-1@gated-at.bofh.it> <skKzD-3op-1@gated-at.bofh.it> <skZfk-3Wc-9@gated-at.bofh.it> <soHWy-1q9-13@gated-at.bofh.it> <soI6d-1wm-1@gated-at.bofh.it>
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On Tue, Oct 4, 2016 at 5:12 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Tue, Oct 4, 2016 at 5:00 PM, Luis R. Rodriguez <mcgrof@kernel.org> wrote:
>>
>> I am not sure how/why a firmware loading daemon would be a better
>> idea now. What Marc describes that Josh proposed with signals for
>> userspcae seems more aligned with what we likely need
>
> Quite frankly, I doubt you want a signal.
>
> You will want to have some way to specify where the firmware files
> are. Right now we have "fw_path[]" which is hardcoded except for the
> first entry that can be set as a module parameter. But you'd probably
> want to expand on that, which implies some /sys or /proc interface.
>
> And once you do that, wouldn't it make more sense to just make the
> "update the firmware path /proc/sys/kernel/fw_path file" make things
> re-search for firmware?

We can, but re-searching for firmware assumes we cache pending
firmware, we currently don't, we just either process sync or async
firmware requests.

> In other words, the interface has to be something *sensible*. Not some
> idiotic ad-hoc "send a signal" (of which that stupid original patch
> was just a very odd example).

Note that the races are beyond firmware, so all
kernel_read_file_from_path() users, as such re-using such old /sys/
interafeces for firmware will not suffice to cover all ground now for
the same race for other possible users.

 Luis

Thread

Re: [RFC] fs: add userspace critical mounts event support "Herbert, Marc" <marc.herbert@intel.com> - 2016-09-24 04:10 +0200
  Re: [RFC] fs: add userspace critical mounts event support Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-09-24 19:50 +0200
    Re: [RFC] fs: add userspace critical mounts event support "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-10-05 02:10 +0200
      Re: [RFC] fs: add userspace critical mounts event support Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 02:20 +0200
        Re: [RFC] fs: add userspace critical mounts event support "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-10-05 02:30 +0200
          Re: [RFC] fs: add userspace critical mounts event support Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 02:40 +0200
            Re: [RFC] fs: add userspace critical mounts event support "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-10-05 19:40 +0200
        Re: [RFC] fs: add userspace critical mounts event support Josh Triplett <josh@joshtriplett.org> - 2016-10-05 03:50 +0200
          Re: [RFC] fs: add userspace critical mounts event support Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 04:00 +0200

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