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    Subject[PATCH 02/20] KASAN: remove code paths guarded by CONFIG_SLAB
    Date
    With SLAB removed and SLUB the only remaining allocator, we can clean up
    some code that was depending on the choice.

    Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
    ---
    mm/kasan/common.c | 13 ++-----------
    mm/kasan/kasan.h | 3 +--
    mm/kasan/quarantine.c | 7 -------
    3 files changed, 3 insertions(+), 20 deletions(-)

    diff --git a/mm/kasan/common.c b/mm/kasan/common.c
    index 256930da578a..5d95219e69d7 100644
    --- a/mm/kasan/common.c
    +++ b/mm/kasan/common.c
    @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
    * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
    * accessed after being freed. We preassign tags for objects in these
    * caches as well.
    - * 3. For SLAB allocator we can't preassign tags randomly since the freelist
    - * is stored as an array of indexes instead of a linked list. Assign tags
    - * based on objects indexes, so that objects that are next to each other
    - * get different tags.
    */
    static inline u8 assign_tag(struct kmem_cache *cache,
    const void *object, bool init)
    @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache,
    if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
    return init ? KASAN_TAG_KERNEL : kasan_random_tag();

    - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
    -#ifdef CONFIG_SLAB
    - /* For SLAB assign tags based on the object index in the freelist. */
    - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
    -#else
    /*
    - * For SLUB assign a random tag during slab creation, otherwise reuse
    + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
    + * assign a random tag during slab creation, otherwise reuse
    * the already assigned tag.
    */
    return init ? kasan_random_tag() : get_tag(object);
    -#endif
    }

    void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
    diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
    index 8b06bab5c406..eef50233640a 100644
    --- a/mm/kasan/kasan.h
    +++ b/mm/kasan/kasan.h
    @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags);
    void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
    void kasan_save_free_info(struct kmem_cache *cache, void *object);

    -#if defined(CONFIG_KASAN_GENERIC) && \
    - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
    +#ifdef CONFIG_KASAN_GENERIC
    bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
    void kasan_quarantine_reduce(void);
    void kasan_quarantine_remove_cache(struct kmem_cache *cache);
    diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
    index ca4529156735..138c57b836f2 100644
    --- a/mm/kasan/quarantine.c
    +++ b/mm/kasan/quarantine.c
    @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
    {
    void *object = qlink_to_object(qlink, cache);
    struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
    - unsigned long flags;
    -
    - if (IS_ENABLED(CONFIG_SLAB))
    - local_irq_save(flags);

    /*
    * If init_on_free is enabled and KASAN's free metadata is stored in
    @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
    *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;

    ___cache_free(cache, object, _THIS_IP_);
    -
    - if (IS_ENABLED(CONFIG_SLAB))
    - local_irq_restore(flags);
    }

    static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
    --
    2.42.1
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