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From: Miroslav Benes <mbenes@suse.cz>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Seth Jennings <sjenning@redhat.com>,
	Jiri Kosina <jkosina@suse.cz>, Vojtech Pavlik <vojtech@suse.cz>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 6/9] livepatch: create per-task consistency model
Date: Wed, 18 Feb 2015 14:42:06 +0100 (CET)	[thread overview]
Message-ID: <alpine.LNX.2.00.1502181441490.26278@pobox.suse.cz> (raw)
In-Reply-To: <20150218131526.GB8611@treble.redhat.com>

On Wed, 18 Feb 2015, Josh Poimboeuf wrote:

> On Wed, Feb 18, 2015 at 01:42:56PM +0100, Miroslav Benes wrote:
> > On Tue, 17 Feb 2015, Josh Poimboeuf wrote:
> > 
> > > On Tue, Feb 17, 2015 at 04:48:39PM +0100, Miroslav Benes wrote:
> > > > On Tue, 17 Feb 2015, Josh Poimboeuf wrote:
> > > > 
> > > > > On Mon, Feb 16, 2015 at 03:19:10PM +0100, Miroslav Benes wrote:
> > > 
> > > > > > and externs for functions are redundant.
> > > > > 
> > > > > I agree, but it seems to be the norm in Linux.  I have no idea why.  I'm
> > > > > just following the existing convention.
> > > > 
> > > > Yes, I know. It seems that each author does it differently. You can find 
> > > > both forms even in one header file in the kernel. There is no functional 
> > > > difference AFAIK (it is not the case for variables of course). So as long 
> > > > as we are consistent I do not care. And since we have externs already in 
> > > > livepatch.h... you can scratch this remark if you want to :)
> > > 
> > > Ok.  If there are no objections, let's stick with our existing
> > > nonsensical convention for now :-)
> > 
> > So I was thinking about it again and we should not use bad patterns in our 
> > code from the beginning. Externs do not make sense so let's get rid of 
> > them everywhere (i.e. in the consistency model and also in livepatch.h). 
> > 
> > The C specification talks about extern in context of internal and external 
> > linkages or in context of inline functions but it does not make any sense 
> > to me. Could you look at the specification and tell me if it makes any 
> > sense to you, please?
> 
> Relevant parts from C11:
> 
> 	For an identifier declared with the storage-class specifier extern in a
> 	scope in which a prior declaration of that identifier is visible, if the
> 	prior declaration specifies internal or external linkage, the linkage of
> 	the identifier at the later declaration is the same as the linkage
> 	specified at the prior declaration.  If no prior declaration is visible,
> 	or if the prior declaration specifies no linkage, then the identifier
> 	has external linkage.
> 
> 	If the declaration of an identifier for a function has no storage-class
> 	specifier, its linkage is determined exactly as if it were declared with
> 	the storage-class specifier extern .If the declaration of an identifier
> 	for an object has file scope and no storage-class specifier, its linkage
> 	is external.
> 
> Sounds to me like "extern" is redundant for functions.  I'm fine with
> removing it.  Care to work up a patch for livepatch.h?

Agreed. I'll do that. Thanks.

Miroslav

  reply	other threads:[~2015-02-18 13:42 UTC|newest]

Thread overview: 106+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-09 17:31 [RFC PATCH 0/9] livepatch: consistency model Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 1/9] livepatch: simplify disable error path Josh Poimboeuf
2015-02-13 12:25   ` Miroslav Benes
2015-02-18 17:03     ` Petr Mladek
2015-02-18 20:07   ` Jiri Kosina
2015-02-09 17:31 ` [RFC PATCH 2/9] livepatch: separate enabled and patched states Josh Poimboeuf
2015-02-10 16:44   ` Jiri Slaby
2015-02-10 17:21     ` Josh Poimboeuf
2015-02-13 12:57   ` Miroslav Benes
2015-02-13 14:39     ` Josh Poimboeuf
2015-02-13 14:46       ` Miroslav Benes
2015-02-09 17:31 ` [RFC PATCH 3/9] livepatch: move patching functions into patch.c Josh Poimboeuf
2015-02-10 18:27   ` Jiri Slaby
2015-02-10 18:50     ` Josh Poimboeuf
2015-02-13 14:28   ` Miroslav Benes
2015-02-13 15:09     ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 4/9] livepatch: get function sizes Josh Poimboeuf
2015-02-10 18:30   ` Jiri Slaby
2015-02-10 18:53     ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 5/9] sched: move task rq locking functions to sched.h Josh Poimboeuf
2015-02-10 10:48   ` Masami Hiramatsu
2015-02-10 14:54     ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 6/9] livepatch: create per-task consistency model Josh Poimboeuf
2015-02-10 10:58   ` Masami Hiramatsu
2015-02-10 14:59     ` Josh Poimboeuf
2015-02-10 15:59   ` Miroslav Benes
2015-02-10 16:56     ` Josh Poimboeuf
2015-02-11 16:28       ` Miroslav Benes
2015-02-11 20:23         ` Josh Poimboeuf
2015-02-10 19:27   ` Seth Jennings
2015-02-10 19:32     ` Josh Poimboeuf
2015-02-11 10:21   ` Miroslav Benes
2015-02-11 20:19     ` Josh Poimboeuf
2015-02-12 10:45       ` Miroslav Benes
2015-02-12  3:21   ` Josh Poimboeuf
2015-02-12 11:56     ` Peter Zijlstra
2015-02-12 12:25       ` Jiri Kosina
2015-02-12 12:36         ` Peter Zijlstra
2015-02-12 12:39           ` Jiri Kosina
2015-02-12 12:39         ` Peter Zijlstra
2015-02-12 12:42           ` Jiri Kosina
2015-02-12 13:01             ` Josh Poimboeuf
2015-02-12 12:51       ` Josh Poimboeuf
2015-02-12 13:08         ` Peter Zijlstra
2015-02-12 13:16           ` Jiri Kosina
2015-02-12 14:20             ` Josh Poimboeuf
2015-02-12 14:27               ` Jiri Kosina
2015-02-12 13:16           ` Jiri Slaby
2015-02-12 13:35             ` Peter Zijlstra
2015-02-12 14:08               ` Jiri Kosina
2015-02-12 15:24                 ` Josh Poimboeuf
2015-02-12 14:20               ` Jiri Slaby
2015-02-12 14:32           ` Jiri Kosina
2015-02-18 20:17             ` Ingo Molnar
2015-02-18 20:44               ` Vojtech Pavlik
2015-02-19  9:52                 ` Peter Zijlstra
2015-02-19 10:11                   ` Vojtech Pavlik
2015-02-19 10:51                     ` Peter Zijlstra
2015-02-12 13:26     ` Jiri Slaby
2015-02-12 15:48       ` Josh Poimboeuf
2015-02-14 11:40   ` Jiri Slaby
2015-02-17 14:59     ` Josh Poimboeuf
2015-02-16 14:19   ` Miroslav Benes
2015-02-17 15:10     ` Josh Poimboeuf
2015-02-17 15:48       ` Miroslav Benes
2015-02-17 16:01         ` Josh Poimboeuf
2015-02-18 12:42           ` Miroslav Benes
2015-02-18 13:15             ` Josh Poimboeuf
2015-02-18 13:42               ` Miroslav Benes [this message]
2015-02-09 17:31 ` [RFC PATCH 7/9] proc: add /proc/<pid>/universe to show livepatch status Josh Poimboeuf
2015-02-10 18:47   ` Jiri Slaby
2015-02-10 18:57     ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 8/9] livepatch: allow patch modules to be removed Josh Poimboeuf
2015-02-10 19:02   ` Jiri Slaby
2015-02-10 19:57     ` Josh Poimboeuf
2015-02-11 10:55       ` Jiri Slaby
2015-02-11 18:39         ` Josh Poimboeuf
2015-02-12 15:22     ` Miroslav Benes
2015-02-13 12:44       ` Josh Poimboeuf
2015-02-13 16:04       ` Josh Poimboeuf
2015-02-13 16:17         ` Miroslav Benes
2015-02-13 20:49           ` Josh Poimboeuf
2015-02-16 16:06             ` Miroslav Benes
2015-02-17 15:55               ` Josh Poimboeuf
2015-02-17 16:38                 ` Miroslav Benes
2015-02-09 17:31 ` [RFC PATCH 9/9] livepatch: update task universe when exiting kernel Josh Poimboeuf
2015-02-16 10:16   ` Jiri Slaby
2015-02-17 14:58     ` Josh Poimboeuf
2015-02-09 23:15 ` [RFC PATCH 0/9] livepatch: consistency model Jiri Kosina
2015-02-10  3:05   ` Josh Poimboeuf
2015-02-10  7:21     ` Jiri Kosina
2015-02-10  8:57 ` Jiri Kosina
2015-02-10 14:43   ` Josh Poimboeuf
2015-02-10 11:16 ` Masami Hiramatsu
2015-02-10 15:59   ` Josh Poimboeuf
2015-02-10 17:29     ` Josh Poimboeuf
2015-02-13 10:14 ` Jiri Kosina
2015-02-13 14:19   ` Josh Poimboeuf
2015-02-13 14:22     ` Jiri Kosina
2015-02-13 14:40       ` Miroslav Benes
2015-02-13 14:55         ` Josh Poimboeuf
2015-02-13 14:41       ` Josh Poimboeuf
2015-02-24 11:27         ` Masami Hiramatsu
2015-03-10 16:23 ` Josh Poimboeuf
2015-03-10 21:02   ` Jiri Kosina
2015-03-10 21:30     ` Josh Poimboeuf

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