From: Joe Lawrence <joe.lawrence@redhat.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Jiri Kosina <jikos@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>, Jason Baron <jbaron@akamai.com>,
Evgenii Shatokhin <eshatokhin@virtuozzo.com>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Jessica Yu <jeyu@kernel.org>
Subject: Re: [PATCH v14 03/11] livepatch: Consolidate klp_free functions
Date: Thu, 6 Dec 2018 09:23:47 -0500 [thread overview]
Message-ID: <d4dcf407-462a-e6bd-7ab5-6d27fbcccb99@redhat.com> (raw)
In-Reply-To: <20181206081501.jkki7hg4u43fqwth@pathway.suse.cz>
On 12/06/2018 03:15 AM, Petr Mladek wrote:
> On Wed 2018-12-05 14:02:20, Joe Lawrence wrote:
>> On Thu, Nov 29, 2018 at 10:44:23AM +0100, Petr Mladek wrote:
>>> The code for freeing livepatch structures is a bit scattered and tricky:
>>>
>>> [ ... snip ... ]
>>>
>>> +static int klp_init_patch(struct klp_patch *patch)
>>> +{
>>> + struct klp_object *obj;
>>> + int ret;
>>> +
>>> + mutex_lock(&klp_mutex);
>>> +
>>> + ret = klp_init_patch_before_free(patch);
>>> if (ret) {
>>> mutex_unlock(&klp_mutex);
>>> return ret;
>>> }
>>>
>>
>> I believe klp_init_patch_before_free() accumulates more responsibilities
>> later in the patchset, but I'll ask here: does it really need the
>> klp_mutex since it looks to be operating only on the klp_patch, its
>> objects and functions?
>
> I do not have a strong opinion about it.
>
> On one hand, we are manipulating all the structures and should prevent
> any parallel use. On the other hand, the rest of the code will not
> touch the patch until it is added into klp_patches list or until
> the sysfs interface is created.
>
> If you think that it might cause false expectations and confusions
> then I could move it out of the lock.
I didn't find it confusing, nor is it performance limiting. I figured I
would point it out in case there was some reason for the mutex that I
had missed.
> Well, in the final version we need to call klp_check_patch_conflict()
> under the mutex.
That's right.
-- Joe
next prev parent reply other threads:[~2018-12-06 14:23 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 9:44 [PATCH v14 00/11] livepatch: Atomic replace feature Petr Mladek
2018-11-29 9:44 ` [PATCH v14 01/11] livepatch: Change unsigned long old_addr -> void *old_func in struct klp_func Petr Mladek
2018-12-03 13:24 ` Miroslav Benes
2018-12-05 18:45 ` Joe Lawrence
2018-12-06 11:08 ` Alice Ferrazzi
2018-11-29 9:44 ` [PATCH v14 02/11] livepatch: Shuffle klp_enable_patch()/klp_disable_patch() code Petr Mladek
2018-12-03 13:36 ` Miroslav Benes
2018-12-05 18:45 ` Joe Lawrence
2018-11-29 9:44 ` [PATCH v14 03/11] livepatch: Consolidate klp_free functions Petr Mladek
2018-12-03 14:59 ` Miroslav Benes
2018-12-04 14:00 ` Petr Mladek
2018-12-13 22:35 ` Josh Poimboeuf
2018-12-14 9:37 ` Miroslav Benes
2018-12-05 19:02 ` Joe Lawrence
2018-12-06 8:15 ` Petr Mladek
2018-12-06 14:23 ` Joe Lawrence [this message]
2018-12-13 22:10 ` Josh Poimboeuf
2018-12-14 9:32 ` Petr Mladek
2018-12-14 14:23 ` Josh Poimboeuf
2018-11-29 9:44 ` [PATCH v14 04/11] livepatch: Refuse to unload only livepatches available during a forced transition Petr Mladek
2018-12-03 15:29 ` Miroslav Benes
2018-12-06 8:46 ` Petr Mladek
2018-12-06 9:18 ` Miroslav Benes
2018-12-05 19:05 ` Joe Lawrence
2018-12-13 22:17 ` Josh Poimboeuf
2018-11-29 9:44 ` [PATCH v14 05/11] livepatch: Simplify API by removing registration step Petr Mladek
2018-12-04 12:54 ` Miroslav Benes
2018-12-04 14:47 ` Petr Mladek
2018-12-04 15:32 ` Miroslav Benes
2018-12-05 19:32 ` Joe Lawrence
2018-12-06 8:28 ` Petr Mladek
2018-12-06 9:23 ` Miroslav Benes
2018-12-06 10:14 ` Petr Mladek
2018-12-06 14:36 ` Joe Lawrence
2018-12-13 22:29 ` Josh Poimboeuf
2018-12-14 9:40 ` Petr Mladek
2018-12-14 14:24 ` Josh Poimboeuf
2019-01-03 11:47 ` Petr Mladek
2018-12-13 22:46 ` Josh Poimboeuf
2018-12-14 10:02 ` Petr Mladek
2018-12-14 14:27 ` Josh Poimboeuf
2018-11-29 9:44 ` [PATCH v14 06/11] livepatch: Use lists to manage patches, objects and functions Petr Mladek
2018-12-04 14:13 ` Miroslav Benes
2018-12-05 19:34 ` Joe Lawrence
2018-11-29 9:44 ` [PATCH v14 07/11] livepatch: Add atomic replace Petr Mladek
2018-12-04 15:27 ` Miroslav Benes
2018-12-05 19:37 ` Joe Lawrence
2018-12-13 22:55 ` Josh Poimboeuf
2018-12-17 15:27 ` Petr Mladek
2019-01-03 12:47 ` Petr Mladek
2019-01-03 13:37 ` Josh Poimboeuf
2018-11-29 9:44 ` [PATCH v14 08/11] livepatch: Remove Nop structures when unused Petr Mladek
2018-12-04 16:08 ` Miroslav Benes
2018-12-05 20:17 ` Joe Lawrence
2018-12-13 23:00 ` Josh Poimboeuf
2018-12-17 15:54 ` Petr Mladek
2018-12-17 16:11 ` Josh Poimboeuf
2018-11-29 9:44 ` [PATCH v14 09/11] livepatch: Atomic replace and cumulative patches documentation Petr Mladek
2018-12-04 16:12 ` Miroslav Benes
2018-12-05 20:20 ` Joe Lawrence
2018-11-29 9:44 ` [PATCH v14 10/11] livepatch: Remove ordering and refuse loading conflicting patches Petr Mladek
2018-12-05 10:27 ` Miroslav Benes
2018-12-05 20:24 ` Joe Lawrence
2018-12-13 23:06 ` Josh Poimboeuf
2018-12-17 16:07 ` Petr Mladek
2018-12-17 16:27 ` Josh Poimboeuf
2018-12-18 8:51 ` Petr Mladek
2018-11-29 9:44 ` [PATCH v14 11/11] selftests/livepatch: introduce tests Petr Mladek
2018-12-05 11:38 ` Miroslav Benes
2018-12-05 20:27 ` Joe Lawrence
2018-12-08 16:54 ` Alice Ferrazzi
2018-12-05 20:49 ` [PATCH v14 00/11] livepatch: Atomic replace feature Joe Lawrence
2018-12-06 7:54 ` Petr Mladek
2018-12-06 9:32 ` Miroslav Benes
2018-12-06 10:15 ` Petr Mladek
2018-12-06 12:37 ` Petr Mladek
2018-12-06 14:29 ` Joe Lawrence
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d4dcf407-462a-e6bd-7ab5-6d27fbcccb99@redhat.com \
--to=joe.lawrence@redhat.com \
--cc=eshatokhin@virtuozzo.com \
--cc=jbaron@akamai.com \
--cc=jeyu@kernel.org \
--cc=jikos@kernel.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=live-patching@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=pmladek@suse.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).