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    SubjectRe: [PATCH mm v3 09/19] kasan: open-code kasan_unpoison_slab
    On Fri, Nov 13, 2020 at 11:19PM +0100, Andrey Konovalov wrote:
    > There's the external annotation kasan_unpoison_slab() that is currently
    > defined as static inline and uses kasan_unpoison_range(). Open-code this
    > function in mempool.c. Otherwise with an upcoming change this function
    > will result in an unnecessary function call.
    >
    > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
    > Link: https://linux-review.googlesource.com/id/Ia7c8b659f79209935cbaab3913bf7f082cc43a0e

    Reviewed-by: Marco Elver <elver@google.com>

    Thank you!

    I also think this change made the code more readable, as
    kasan_unpoison_slab() made me think it's unpoisoning the *whole* slab,
    which is clearly not the case.

    > ---
    > include/linux/kasan.h | 6 ------
    > mm/mempool.c | 2 +-
    > 2 files changed, 1 insertion(+), 7 deletions(-)
    >
    > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
    > index 1594177f86bb..872bf145ddde 100644
    > --- a/include/linux/kasan.h
    > +++ b/include/linux/kasan.h
    > @@ -106,11 +106,6 @@ struct kasan_cache {
    > int free_meta_offset;
    > };
    >
    > -size_t __ksize(const void *);
    > -static inline void kasan_unpoison_slab(const void *ptr)
    > -{
    > - kasan_unpoison_range(ptr, __ksize(ptr));
    > -}
    > size_t kasan_metadata_size(struct kmem_cache *cache);
    >
    > bool kasan_save_enable_multi_shot(void);
    > @@ -166,7 +161,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
    > return false;
    > }
    >
    > -static inline void kasan_unpoison_slab(const void *ptr) { }
    > static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
    >
    > #endif /* CONFIG_KASAN */
    > diff --git a/mm/mempool.c b/mm/mempool.c
    > index f473cdddaff0..583a9865b181 100644
    > --- a/mm/mempool.c
    > +++ b/mm/mempool.c
    > @@ -112,7 +112,7 @@ static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
    > static void kasan_unpoison_element(mempool_t *pool, void *element)
    > {
    > if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
    > - kasan_unpoison_slab(element);
    > + kasan_unpoison_range(element, __ksize(element));
    > else if (pool->alloc == mempool_alloc_pages)
    > kasan_alloc_pages(element, (unsigned long)pool->pool_data);
    > }
    > --
    > 2.29.2.299.gdc1121823c-goog
    >

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