linux-kernel - Re: [PATCH 2/2] livepatch: introduce patch/func-walking helpers

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Message-ID: <20150523132309.GA8636@dhcp-128-1.nay.redhat.com>
Date:	Sat, 23 May 2015 21:23:09 +0800
From:	Minfei Huang <mhuang@...hat.com>
To:	Jiri Slaby <jslaby@...e.cz>
Cc:	Minfei Huang <mnfhuang@...il.com>, Jiri Kosina <jkosina@...e.cz>,
	live-patching@...r.kernel.org, jpoimboe@...hat.com,
	sjenning@...hat.com, vojtech@...e.cz, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] livepatch: introduce patch/func-walking helpers

On 05/20/15 at 09:11am, Jiri Slaby wrote:
> On 05/20/2015, 03:51 AM, Minfei Huang wrote:
> > Sure. Sorry for confuse you with my comment.
> 
> Oh, I see now, but:
> 
> > list_for_each_entry(patch, &klp_patches, list) {
> > 	for (obj = patch->objs; obj->funcs; obj++) {
> > ----------------------------------
> > We get the fisrt object from the patch, then we break the loop. The code is more clearly to
> > use "if", instead of the loop.
> > ----------------------------------
> > 		if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
> > 			continue;
> 
> See 'continue' here. This *is* a loop and we do not fetch the first
> object. We look for the one with the same name.
> 
> > 		if (action == MODULE_STATE_COMING) {
> > 			obj->mod = mod;
> > 			klp_module_notify_coming(patch, obj);
> > 		} else /* MODULE_STATE_GOING */
> > 			klp_module_notify_going(patch, obj);
> > 
> > 		break;
> > ----------------------------------
> > Here we break the loop.
> 
> Only if we found the one.
> 

Hi, Jiri.

Ooops!

Since it is impossible for the differect objects which have the some
name in one patch, it is right to break the loop once we find a matched
object. It confuses me with the logic in __klp_enable_patch.

Thanks for your explanation.

Thanks
Minfei
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