[v2,2/5] mm/sl[au]b: unify __ksize()

Commit Message

Hyeonggon Yoo March 4, 2022, 6:34 a.m. UTC

Now that SLAB passes large requests to page allocator like SLUB,
Unify __ksize(). Only SLOB need to implement own version of __ksize()
because it stores size in object header for kmalloc objects.

Signed-off-by: Hyeonggon Yoo <[e-mail]>
---
 mm/slab.c        | 30 ------------------------------
 mm/slab_common.c | 27 +++++++++++++++++++++++++++
 mm/slub.c        | 16 ----------------
 3 files changed, 27 insertions(+), 46 deletions(-)

Comments

Vlastimil Babka March 4, 2022, 6:25 p.m. UTC | #1

On 3/4/22 07:34, Hyeonggon Yoo wrote:
> Now that SLAB passes large requests to page allocator like SLUB,
> Unify __ksize(). Only SLOB need to implement own version of __ksize()
> because it stores size in object header for kmalloc objects.
> 
> Signed-off-by: Hyeonggon Yoo <[e-mail]>

Reviewed-by: Vlastimil Babka <[e-mail]>

As discussed, we can be more specific about the !folio_test_slab() case, but
that can be done on top.

Hyeonggon Yoo March 5, 2022, 4:02 a.m. UTC | #2

On Fri, Mar 04, 2022 at 07:25:47PM +0100, Vlastimil Babka wrote:
> On 3/4/22 07:34, Hyeonggon Yoo wrote:
> > Now that SLAB passes large requests to page allocator like SLUB,
> > Unify __ksize(). Only SLOB need to implement own version of __ksize()
> > because it stores size in object header for kmalloc objects.
> > 
> > Signed-off-by: Hyeonggon Yoo <[e-mail]>
> 
> Reviewed-by: Vlastimil Babka <[e-mail]>
> 
> As discussed, we can be more specific about the !folio_test_slab() case, but
> that can be done on top.

I'll add that in v3. Thanks!

Patch

diff --git a/mm/slab.c b/mm/slab.c
index 570af6dc3478..3ddf2181d8e4 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -4216,33 +4216,3 @@  void __check_heap_object(const void *ptr, unsigned long n,
 	usercopy_abort("SLAB object", cachep->name, to_user, offset, n);
 }
 #endif /* CONFIG_HARDENED_USERCOPY */
-
-/**
- * __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
- */
-size_t __ksize(const void *objp)
-{
-	struct kmem_cache *c;
-	struct folio *folio;
-	size_t size;
-
-	BUG_ON(!objp);
-	if (unlikely(objp == ZERO_SIZE_PTR))
-		return 0;
-
-	folio = virt_to_folio(objp);
-	if (!folio_test_slab(folio))
-		return folio_size(folio);
-
-	c = virt_to_cache(objp);
-	size = c ? c->object_size : 0;
-
-	return size;
-}
-EXPORT_SYMBOL(__ksize);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 23f2ab0713b7..1d2f92e871d2 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1245,6 +1245,33 @@  void kfree_sensitive(const void *p)
 }
 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
+ */
+size_t __ksize(const void *object)
+{
+	struct folio *folio;
+
+	if (unlikely(object == ZERO_SIZE_PTR))
+		return 0;
+
+	folio = virt_to_folio(object);
+
+	if (unlikely(!folio_test_slab(folio)))
+		return folio_size(folio);
+
+	return slab_ksize(folio_slab(folio)->slab_cache);
+}
+EXPORT_SYMBOL(__ksize);
+#endif
+
 /**
  * ksize - get the actual amount of memory allocated for a given object
  * @objp: Pointer to the object
diff --git a/mm/slub.c b/mm/slub.c
index 04fd084f4709..6f0ebadd8f30 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4507,22 +4507,6 @@  void __check_heap_object(const void *ptr, unsigned long n,
 }
 #endif /* CONFIG_HARDENED_USERCOPY */
 
-size_t __ksize(const void *object)
-{
-	struct folio *folio;
-
-	if (unlikely(object == ZERO_SIZE_PTR))
-		return 0;
-
-	folio = virt_to_folio(object);
-
-	if (unlikely(!folio_test_slab(folio)))
-		return folio_size(folio);
-
-	return slab_ksize(folio_slab(folio)->slab_cache);
-}
-EXPORT_SYMBOL(__ksize);
-
 void kfree(const void *x)
 {
 	struct folio *folio;