[PATCH V4 1/3] livepatch: remove 'struct completion finish' from klp_patch

From: Ming Lei
Date: Tue Nov 02 2021 - 10:59:56 EST


The completion finish is just for waiting release of the klp_patch
object, then releases module refcnt. We can simply drop the module
refcnt in the kobject release handler of klp_patch.

This way also helps to support allocating klp_patch from heap.

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
include/linux/livepatch.h | 1 -
kernel/livepatch/core.c | 12 +++---------
2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 2614247a9781..9712818997c5 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -170,7 +170,6 @@ struct klp_patch {
bool enabled;
bool forced;
struct work_struct free_work;
- struct completion finish;
};

#define klp_for_each_object_static(patch, obj) \
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 335d988bd811..b967b4b0071b 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -551,10 +551,10 @@ static int klp_add_nops(struct klp_patch *patch)

static void klp_kobj_release_patch(struct kobject *kobj)
{
- struct klp_patch *patch;
+ struct klp_patch *patch = container_of(kobj, struct klp_patch, kobj);

- patch = container_of(kobj, struct klp_patch, kobj);
- complete(&patch->finish);
+ if (!patch->forced)
+ module_put(patch->mod);
}

static struct kobj_type klp_ktype_patch = {
@@ -678,11 +678,6 @@ static void klp_free_patch_finish(struct klp_patch *patch)
* cannot get enabled again.
*/
kobject_put(&patch->kobj);
- wait_for_completion(&patch->finish);
-
- /* Put the module after the last access to struct klp_patch. */
- if (!patch->forced)
- module_put(patch->mod);
}

/*
@@ -876,7 +871,6 @@ static int klp_init_patch_early(struct klp_patch *patch)
patch->enabled = false;
patch->forced = false;
INIT_WORK(&patch->free_work, klp_free_patch_work_fn);
- init_completion(&patch->finish);

klp_for_each_object_static(patch, obj) {
if (!obj->funcs)
--
2.31.1