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    SubjectRe: [PATCH v7 5/7] livepatch: Support separate list for replaced patches.
    On Tue, 6 Feb 2018, Petr Mladek wrote:

    > From: Jason Baron <jbaron@akamai.com>
    >
    > We are going to add a feature called atomic replace. It will allow to
    > create a patch that would replace all already registered patches.
    >
    > The replaced patches will stay registered because they are typically
    > unregistered by some package uninstall scripts. But we will remove
    > these patches from @klp_patches list to keep the enabled patch
    > on the bottom of the stack. Otherwise, we would need to implement
    > rather complex logic for moving the patches on the stack. Also
    > it would complicate implementation of the atomic replace feature.
    > It is not worth it.
    >
    > As a result, we will have patches that are registered but that
    > are not longer usable. Let's get prepared for this and use
    > a better descriptive name for klp_is_patch_registered() function.
    >
    > Also create separate list for the replaced patches and allow to
    > unregister them. Alternative solution would be to add a flag
    > into struct klp_patch. Note that patch->kobj.state_initialized
    > is not safe because it can be cleared outside klp_mutex.
    >
    > This patch does not change the existing behavior.
    >
    > Signed-off-by: Jason Baron <jbaron@akamai.com>
    > [pmladek@suse.com: Split and renamed klp_is_patch_usable()]
    > Signed-off-by: Petr Mladek <pmladek@suse.com>
    > Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    > Cc: Jessica Yu <jeyu@kernel.org>
    > Cc: Jiri Kosina <jikos@kernel.org>
    > Cc: Miroslav Benes <mbenes@suse.cz>
    > ---
    > kernel/livepatch/core.c | 30 ++++++++++++++++++++++++------
    > 1 file changed, 24 insertions(+), 6 deletions(-)
    >
    > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
    > index fccb603942f1..11632fe8716a 100644
    > --- a/kernel/livepatch/core.c
    > +++ b/kernel/livepatch/core.c
    > @@ -47,6 +47,13 @@ DEFINE_MUTEX(klp_mutex);
    >
    > static LIST_HEAD(klp_patches);
    >
    > +/*
    > + * List of 'replaced' patches that have been replaced by a patch that has the
    > + * 'replace' bit set. When they are added to this list, they are disabled and
    > + * can not be re-enabled, but they can be unregistered().
    > + */
    > +LIST_HEAD(klp_replaced_patches);

    It should be static, I think. It is used only in kernel/livepatch/core.c.
    And sparse complains about it.

    With that fixed

    Acked-by: Miroslav Benes <mbenes@suse.cz>

    Miroslav

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