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SubjectRe: [PATCH v15 03/11] livepatch: Consolidate klp_free functions
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

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