From: Miroslav Benes <mbenes@suse.cz>
To: Petr Mladek <pmladek@suse.com>
Cc: Jiri Kosina <jikos@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jason Baron <jbaron@akamai.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Evgenii Shatokhin <eshatokhin@virtuozzo.com>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Jessica Yu <jeyu@kernel.org>
Subject: Re: [PATCH v15 03/11] livepatch: Consolidate klp_free functions
Date: Wed, 9 Jan 2019 15:35:49 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.21.1901091535210.12972@pobox.suse.cz> (raw)
In-Reply-To: <20190109124329.21991-4-pmladek@suse.com>
On Wed, 9 Jan 2019, Petr Mladek wrote:
> The code for freeing livepatch structures is a bit scattered and tricky:
>
> + direct calls to klp_free_*_limited() and kobject_put() are
> used to release partially initialized objects
>
> + klp_free_patch() removes the patch from the public list
> and releases all objects except for patch->kobj
>
> + object_put(&patch->kobj) and the related wait_for_completion()
> are called directly outside klp_mutex; this code is duplicated;
>
> Now, we are going to remove the registration stage to simplify the API
> and the code. This would require handling more situations in
> klp_enable_patch() error paths.
>
> More importantly, we are going to add a feature called atomic replace.
> It will need to dynamically create func and object structures. We will
> want to reuse the existing init() and free() functions. This would
> create even more error path scenarios.
>
> This patch implements more straightforward free functions:
>
> + checks kobj_added flag instead of @limit[*]
>
> + initializes patch->list early so that the check for empty list
> always works
>
> + The action(s) that has to be done outside klp_mutex are done
> in separate klp_free_patch_finish() function. It waits only
> when patch->kobj was really released via the _start() part.
>
> The patch does not change the existing behavior.
>
> [*] We need our own flag to track that the kobject was successfully
> added to the hierarchy. Note that kobj.state_initialized only
> indicates that kobject has been initialized, not whether is has
> been added (and needs to be removed on cleanup).
>
> Signed-off-by: Petr Mladek <pmladek@suse.com>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Miroslav Benes <mbenes@suse.cz>
> Cc: Jessica Yu <jeyu@kernel.org>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: Jason Baron <jbaron@akamai.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Miroslav
next prev parent reply other threads:[~2019-01-09 14:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 12:43 [PATCH v15 00/11] livepatch: Atomic replace feature Petr Mladek
2019-01-09 12:43 ` [PATCH v15 01/11] livepatch: Change unsigned long old_addr -> void *old_func in struct klp_func Petr Mladek
2019-01-09 12:43 ` [PATCH v15 02/11] livepatch: Shuffle klp_enable_patch()/klp_disable_patch() code Petr Mladek
2019-01-09 12:43 ` [PATCH v15 03/11] livepatch: Consolidate klp_free functions Petr Mladek
2019-01-09 14:35 ` Miroslav Benes [this message]
2019-01-09 12:43 ` [PATCH v15 04/11] livepatch: Don't block the removal of patches loaded after a forced transition Petr Mladek
2019-01-09 14:50 ` Miroslav Benes
2019-01-09 12:43 ` [PATCH v15 05/11] livepatch: Simplify API by removing registration step Petr Mladek
2019-01-10 12:32 ` Miroslav Benes
2019-01-09 12:43 ` [PATCH v15 06/11] livepatch: Use lists to manage patches, objects and functions Petr Mladek
2019-01-09 12:43 ` [PATCH v15 07/11] livepatch: Add atomic replace Petr Mladek
2019-01-10 13:05 ` Miroslav Benes
2019-01-09 12:43 ` [PATCH v15 08/11] livepatch: Remove Nop structures when unused Petr Mladek
2019-01-10 13:42 ` Miroslav Benes
2019-01-09 12:43 ` [PATCH v15 09/11] livepatch: Atomic replace and cumulative patches documentation Petr Mladek
2019-01-09 12:43 ` [PATCH v15 10/11] livepatch: Remove ordering (stacking) of the livepatches Petr Mladek
2019-01-10 13:56 ` Miroslav Benes
2019-01-09 12:43 ` [PATCH v15 11/11] selftests/livepatch: introduce tests Petr Mladek
2019-01-11 17:44 ` [PATCH v15 00/11] livepatch: Atomic replace feature Josh Poimboeuf
2019-01-11 19:56 ` Jiri Kosina
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