2022-03-04 10:19:51

by Hyeonggon Yoo

[permalink] [raw]
Subject: [PATCH v2 3/5] mm/sl[auo]b: move definition of __ksize() to mm/slab.h

__ksize() is only called by KASAN. Remove export symbol and move
definition to mm/slab.h as we don't want to grow its callers.

[ [email protected]: Move definition to mm/slab.h and reduce comments ]

Signed-off-by: Hyeonggon Yoo <[email protected]>
---
include/linux/slab.h | 1 -
mm/slab.h | 2 ++
mm/slab_common.c | 9 +--------
mm/slob.c | 1 -
4 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index e7b3330db4f3..d2b896553315 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -182,7 +182,6 @@ int kmem_cache_shrink(struct kmem_cache *s);
void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __alloc_size(2);
void kfree(const void *objp);
void kfree_sensitive(const void *objp);
-size_t __ksize(const void *objp);
size_t ksize(const void *objp);
#ifdef CONFIG_PRINTK
bool kmem_valid_obj(void *object);
diff --git a/mm/slab.h b/mm/slab.h
index 31e98beb47a3..79b319d58504 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -685,6 +685,8 @@ static inline void free_large_kmalloc(struct folio *folio, void *object)
}
#endif /* CONFIG_SLOB */

+size_t __ksize(const void *objp);
+
static inline size_t slab_ksize(const struct kmem_cache *s)
{
#ifndef CONFIG_SLUB
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 1d2f92e871d2..b126fc7247b9 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1247,13 +1247,7 @@ EXPORT_SYMBOL(kfree_sensitive);

#ifndef CONFIG_SLOB
/**
- * __ksize -- Uninstrumented ksize.
- * @objp: pointer to the object
- *
- * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
- * safety checks as ksize() with KASAN instrumentation enabled.
- *
- * Return: size of the actual memory used by @objp in bytes
+ * __ksize -- Uninstrumented ksize. Only called by KASAN.
*/
size_t __ksize(const void *object)
{
@@ -1269,7 +1263,6 @@ size_t __ksize(const void *object)

return slab_ksize(folio_slab(folio)->slab_cache);
}
-EXPORT_SYMBOL(__ksize);
#endif

/**
diff --git a/mm/slob.c b/mm/slob.c
index 60c5842215f1..d8af6c54f133 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -588,7 +588,6 @@ size_t __ksize(const void *block)
m = (unsigned int *)(block - align);
return SLOB_UNITS(*m) * SLOB_UNIT;
}
-EXPORT_SYMBOL(__ksize);

int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
{
--
2.33.1


2022-03-04 19:59:01

by Vlastimil Babka

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] mm/sl[auo]b: move definition of __ksize() to mm/slab.h

On 3/4/22 07:34, Hyeonggon Yoo wrote:
> __ksize() is only called by KASAN. Remove export symbol and move
> definition to mm/slab.h as we don't want to grow its callers.
>
> [ [email protected]: Move definition to mm/slab.h and reduce comments ]
>
> Signed-off-by: Hyeonggon Yoo <[email protected]>

Reviewed-by: Vlastimil Babka <[email protected]>

> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -685,6 +685,8 @@ static inline void free_large_kmalloc(struct folio *folio, void *object)
> }
> #endif /* CONFIG_SLOB */
>
> +size_t __ksize(const void *objp);
> +
> static inline size_t slab_ksize(const struct kmem_cache *s)
> {
> #ifndef CONFIG_SLUB
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 1d2f92e871d2..b126fc7247b9 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1247,13 +1247,7 @@ EXPORT_SYMBOL(kfree_sensitive);
>
> #ifndef CONFIG_SLOB
> /**

Maybe just /* so it's not even parsed as a kernel-doc anymore?

> - * __ksize -- Uninstrumented ksize.
> - * @objp: pointer to the object
> - *
> - * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
> - * safety checks as ksize() with KASAN instrumentation enabled.
> - *
> - * Return: size of the actual memory used by @objp in bytes
> + * __ksize -- Uninstrumented ksize. Only called by KASAN.
> */
> size_t __ksize(const void *object)
> {
> @@ -1269,7 +1263,6 @@ size_t __ksize(const void *object)
>
> return slab_ksize(folio_slab(folio)->slab_cache);
> }
> -EXPORT_SYMBOL(__ksize);
> #endif
>

2022-03-05 09:25:55

by Hyeonggon Yoo

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] mm/sl[auo]b: move definition of __ksize() to mm/slab.h

On Fri, Mar 04, 2022 at 07:29:21PM +0100, Vlastimil Babka wrote:
> On 3/4/22 07:34, Hyeonggon Yoo wrote:
> > __ksize() is only called by KASAN. Remove export symbol and move
> > definition to mm/slab.h as we don't want to grow its callers.
> >
> > [ [email protected]: Move definition to mm/slab.h and reduce comments ]
> >
> > Signed-off-by: Hyeonggon Yoo <[email protected]>
>
> Reviewed-by: Vlastimil Babka <[email protected]>
>

Thanks!

> > --- a/mm/slab.h
> > +++ b/mm/slab.h
> > @@ -685,6 +685,8 @@ static inline void free_large_kmalloc(struct folio *folio, void *object)
> > }
> > #endif /* CONFIG_SLOB */
> >
> > +size_t __ksize(const void *objp);
> > +
> > static inline size_t slab_ksize(const struct kmem_cache *s)
> > {
> > #ifndef CONFIG_SLUB
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > index 1d2f92e871d2..b126fc7247b9 100644
> > --- a/mm/slab_common.c
> > +++ b/mm/slab_common.c
> > @@ -1247,13 +1247,7 @@ EXPORT_SYMBOL(kfree_sensitive);
> >
> > #ifndef CONFIG_SLOB
> > /**
>
> Maybe just /* so it's not even parsed as a kernel-doc anymore?
>

Oh yes, that would be better.

> > - * __ksize -- Uninstrumented ksize.
> > - * @objp: pointer to the object
> > - *
> > - * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
> > - * safety checks as ksize() with KASAN instrumentation enabled.
> > - *
> > - * Return: size of the actual memory used by @objp in bytes
> > + * __ksize -- Uninstrumented ksize. Only called by KASAN.
> > */
> > size_t __ksize(const void *object)
> > {
> > @@ -1269,7 +1263,6 @@ size_t __ksize(const void *object)
> >
> > return slab_ksize(folio_slab(folio)->slab_cache);
> > }
> > -EXPORT_SYMBOL(__ksize);
> > #endif
> >

--
Thank you, You are awesome!
Hyeonggon :-)