From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Miroslav Benes <mbenes@suse.cz>
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 3/9] livepatch: move patching functions into patch.c
Date: Fri, 13 Feb 2015 09:09:11 -0600 [thread overview]
Message-ID: <20150213150911.GF27180@treble.redhat.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1502131508510.14133@pobox.suse.cz>
On Fri, Feb 13, 2015 at 03:28:28PM +0100, Miroslav Benes wrote:
> On Mon, 9 Feb 2015, Josh Poimboeuf wrote:
>
> > Move functions related to the actual patching of functions and objects
> > into a new patch.c file.
>
> I am definitely for splitting the code to several different files.
> Otherwise it would be soon unmanageable. However I don't know if this
> patch is the best possible. Maybe it is just nitpicking so let's not spend
> too much time on this :)
>
> Without this patch there are several different groups of functions in
> core.c:
> 1. infrastructure such as global variables, klp_init and some helper
> functions
> 2. (un)registration and initialization of the patch
> 3. enable/disable with patching/unpatching, ftrace handler
> 4. sysfs code
> 5. module notifier
> 6. relocations
>
> I would move sysfs code away to separate file.
I'm not sure about moving the sysfs code to its own file, mainly because
of enabled_store():
1. It needs the klp_mutex. It's really nice and clean to keep the
klp_mutex a static variable in core.c (which I plan on doing in v2 of
the patch set).
2. It's one of the main entry points into the klp code, along with
register/unregister and enable/disable. It makes a lot of sense to
keep all of those entry points in the same file IMO.
> If we decide to move patching code I think it would make sense to move
> enable/disable functions along with it. Or perhaps __klp_enable_patch and
> __klp_disable_patch only. It is possible though that the result would be
> much worse.
I would vote to keep enable/disable in core.c for the same reasons as
stated above for enabled_store(). It's possible that
__klp_enable_patch() and __klp_disable_patch() could be moved elsewhere.
Personally I like them where they are, since they call into both
"transition" functions and "patch" functions.
So, big surprise, I agree with my own code splitting decisions ;-)
>
> Or we can move some other group of functions...
>
> [...]
>
> > diff --git a/kernel/livepatch/patch.h b/kernel/livepatch/patch.h
> > new file mode 100644
> > index 0000000..bb34bd3
> > --- /dev/null
> > +++ b/kernel/livepatch/patch.h
> > @@ -0,0 +1,25 @@
> > +#include <linux/livepatch.h>
> > +
> > +/**
> > + * struct klp_ops - structure for tracking registered ftrace ops structs
> > + *
> > + * A single ftrace_ops is shared between all enabled replacement functions
> > + * (klp_func structs) which have the same old_addr. This allows the switch
> > + * between function versions to happen instantaneously by updating the klp_ops
> > + * struct's func_stack list. The winner is the klp_func at the top of the
> > + * func_stack (front of the list).
> > + *
> > + * @node: node for the global klp_ops list
> > + * @func_stack: list head for the stack of klp_func's (active func is on top)
> > + * @fops: registered ftrace ops struct
> > + */
> > +struct klp_ops {
> > + struct list_head node;
> > + struct list_head func_stack;
> > + struct ftrace_ops fops;
> > +};
> > +
> > +struct klp_ops *klp_find_ops(unsigned long old_addr);
> > +
> > +extern int klp_patch_object(struct klp_object *obj);
> > +extern void klp_unpatch_object(struct klp_object *obj);
>
> Is there a reason why klp_find_ops is not extern and the other two
> functions are? I think it is redundant and it is better to be consistent.
Good catch, thanks.
--
Josh
next prev parent reply other threads:[~2015-02-13 15:09 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 [this message]
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
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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