lkml.org 
[lkml]   [2013]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] firmware: Avoid superfluous usermodehelper lock
At Wed, 8 May 2013 23:52:02 +0800,
Ming Lei wrote:
>
> On Wed, May 8, 2013 at 2:56 PM, Takashi Iwai <tiwai@suse.de> wrote:
> > When a firmware file can be loaded directly, there is no good reason
> > to lock usermodehelper. It's needed only when the direct fw load
> > fails and falls back to the user-mode helper.
>
> I remembered that we discussed the problem before, :-)
>
> Some crazy drivers might call request_firmware inside resume callback
> (for example, USB devices might be rebind in resume), with
> usermodehelper_read_lock, we can find the mistake easily and log it.
>
> I am wondering if it is good to remove the usermodehelper lock.
>
> Could you let us know any benefit to do it?

Well, the question is whether usermodehelper lock is really an
appropriate stuff for *checking* the availability of direct fs
access. I find it doesn't fit well any longer, in the situation where
no actual user-space call is needed. Though, I'm not quite sure which
lock or flag can be used instead...


Takashi



\
 
 \ /
  Last update: 2013-05-08 19:01    [W:0.119 / U:0.360 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site