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From: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>
To: Colin Cross <ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
Cc: lkml <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Trond Myklebust
	<Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
	Len Brown <len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>,
	Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
	Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"J. Bruce Fields"
	<bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Mandeep Singh Baines
	<msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Paul Walmsley <paul-DWxLp4Yu+b8AvxtiuMwx3w@public.gmane.org>,
	Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
	"Eric W. Biederman"
	<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
	Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Linux PM list <linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Linus Torvalds
	<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Ben Chan <benchan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Subject: Re: [PATCH 1/2] freezer: add unsafe versions of freezable helpers
Date: Sun, 5 May 2013 00:55:49 +0200	[thread overview]
Message-ID: <20130504225549.GA24276@amd.pavel.ucw.cz> (raw)
In-Reply-To: <CAMbhsRS6+hjTmrihVzgu3Dtyp8XAhJJ4VKMj=28G6xH3H73=6Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

Hi!

> >> NFS calls the freezable helpers with locks held, which is unsafe
> >> and caused lockdep warnings when 6aa9707 "lockdep: check that no
> >> locks held at freeze time" was applied (reverted in dbf520a).
> >> Add new *_unsafe versions of the helpers that will not run the
> >> lockdep test when 6aa9707 is reapplied, and call them from NFS.
> >>
> >> Signed-off-by: Colin Cross <ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
> >
> > Looks mostly good.
> >
> >> @@ -152,6 +169,14 @@ static inline bool freezer_should_skip(struct task_struct *p)
> >>       freezer_count();                                                \
> >>  })
> >>
> >> +/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
> >> +#define freezable_schedule_unsafe()                                  \
> >> +({                                                                   \
> >> +     freezer_do_not_count();                                         \
> >> +     schedule();                                                     \
> >> +     freezer_count_unsafe();                                         \
> >> +})
> >> +
> >
> > Make it inline function? :-). Add short explanation why it is good
> > idea?
> 
> These are exact copies of the existing non-unsafe versions, except
> they call freezer_count_unsafe() instead of freezer_count().  The next
> version of my other patch stack that goes on top of this has a patch
> to convert the macros in this file to static inline functions (at
> least the ones that can be).  I'd rather not mix it in with this patch
> for ease of comparison with the existing calls.

Ok.

Acked-by: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>

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  parent reply	other threads:[~2013-05-04 22:55 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-03 21:04 [PATCH 1/2] freezer: add unsafe versions of freezable helpers Colin Cross
2013-05-03 21:04 ` [PATCH 2/2] lockdep: check that no locks held at freeze time Colin Cross
     [not found]   ` <1367615050-3894-2-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-04 13:04     ` Pavel Machek
2013-05-04 20:27       ` Colin Cross
2013-05-04 22:57         ` Pavel Machek
     [not found]           ` <20130504225715.GB24276-tWAi6jLit6GreWDznjuHag@public.gmane.org>
2013-05-04 23:49             ` Colin Cross
2013-05-05  0:05               ` Pavel Machek
     [not found]                 ` <20130505000528.GA25454-tWAi6jLit6GreWDznjuHag@public.gmane.org>
2013-05-05  0:23                   ` Colin Cross
     [not found]                     ` <CAMbhsRQso4fW_DVL6U3zfbX3YbLsTy8-rUA-fo61Aw93bU+sQQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-05  1:13                       ` Pavel Machek
2013-05-05  9:18                   ` Ingo Molnar
     [not found]                     ` <20130505091844.GC22239-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-05-06  8:55                       ` Peter Zijlstra
2013-05-06 12:11                         ` Pavel Machek
2013-05-06 14:33                         ` Linus Torvalds
2013-05-06 14:42                           ` Peter Zijlstra
2013-05-06 19:01     ` Tejun Heo
2013-05-06 19:30       ` Colin Cross
2013-05-06 19:33         ` Tejun Heo
2013-05-06 20:06           ` Rafael J. Wysocki
2013-05-04 13:00 ` [PATCH 1/2] freezer: add unsafe versions of freezable helpers Pavel Machek
2013-05-04 20:23   ` Colin Cross
     [not found]     ` <CAMbhsRS6+hjTmrihVzgu3Dtyp8XAhJJ4VKMj=28G6xH3H73=6Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-04 22:55       ` Pavel Machek [this message]
2013-05-05  9:23 ` Ingo Molnar
     [not found]   ` <20130505092318.GD22239-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-05-05 22:12     ` Pavel Machek
     [not found] ` <1367615050-3894-1-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-06  8:50   ` Peter Zijlstra
2013-05-06 10:58     ` Jeff Layton
2013-05-06 18:55   ` Tejun Heo
2013-05-06 10:56 ` Jeff Layton
2013-05-06 19:57   ` Colin Cross
     [not found]     ` <CAMbhsRQsFT2j_CuPL45J03itymcp3PNP8ckt3fAAo+hzavNrbw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-06 21:43       ` Jeff Layton
     [not found]         ` <20130506174336.447d0d75-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2013-05-06 21:54           ` Colin Cross
2013-05-06 21:58             ` Linus Torvalds
2013-05-06 22:05               ` Jeff Layton
2013-05-06 22:11               ` Colin Cross
2013-05-06 22:14               ` Tejun Heo
2013-05-06 21:59             ` Jeff Layton

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