Merge branch 'slab/for-6.12/kmem_cache_args' into slab/for-next

Merge kmem_cache_create() refactoring by Christian Brauner.

Note this includes a merge of the vfs.file tree that contains the
prerequisity kmem_cache_create_rcu() work.

1 files changed, 43 insertions, 96 deletions

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 11ef221bce17..61f32420230a 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -215,32 +215,29 @@ struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
 }
 
 static struct kmem_cache *create_cache(const char *name,
-		unsigned int object_size, unsigned int align,
-		slab_flags_t flags, unsigned int useroffset,
-		unsigned int usersize, void (*ctor)(void *),
-		struct kmem_cache *root_cache)
+				       unsigned int object_size,
+				       struct kmem_cache_args *args,
+				       slab_flags_t flags)
 {
 	struct kmem_cache *s;
 	int err;
 
-	if (WARN_ON(useroffset + usersize > object_size))
-		useroffset = usersize = 0;
+	if (WARN_ON(args->useroffset + args->usersize > object_size))
+		args->useroffset = args->usersize = 0;
+
+	/* If a custom freelist pointer is requested make sure it's sane. */
+	err = -EINVAL;
+	if (args->use_freeptr_offset &&
+	    (args->freeptr_offset >= object_size ||
+	     !(flags & SLAB_TYPESAFE_BY_RCU) ||
+	     !IS_ALIGNED(args->freeptr_offset, sizeof(freeptr_t))))
+		goto out;
 
 	err = -ENOMEM;
 	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
 	if (!s)
 		goto out;
-
-	s->name = name;
-	s->size = s->object_size = object_size;
-	s->align = align;
-	s->ctor = ctor;
-#ifdef CONFIG_HARDENED_USERCOPY
-	s->useroffset = useroffset;
-	s->usersize = usersize;
-#endif
-
-	err = __kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, name, object_size, args, flags);
 	if (err)
 		goto out_free_cache;
 
@@ -255,39 +252,24 @@ out:
 }
 
 /**
- * kmem_cache_create_usercopy - Create a cache with a region suitable
- * for copying to userspace
+ * __kmem_cache_create_args - Create a kmem cache.
  * @name: A string which is used in /proc/slabinfo to identify this cache.
- * @size: The size of objects to be created in this cache.
- * @align: The required alignment for the objects.
- * @flags: SLAB flags
- * @useroffset: Usercopy region offset
- * @usersize: Usercopy region size
- * @ctor: A constructor for the objects.
+ * @object_size: The size of objects to be created in this cache.
+ * @args: Additional arguments for the cache creation (see
+ *        &struct kmem_cache_args).
+ * @flags: See %SLAB_* flags for an explanation of individual @flags.
  *
- * Cannot be called within a interrupt, but can be interrupted.
- * The @ctor is run when new pages are allocated by the cache.
+ * Not to be called directly, use the kmem_cache_create() wrapper with the same
+ * parameters.
  *
- * The flags are
- *
- * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
- * to catch references to uninitialised memory.
- *
- * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
- * for buffer overruns.
- *
- * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
- * cacheline.  This can be beneficial if you're counting cycles as closely
- * as davem.
+ * Context: Cannot be called within a interrupt, but can be interrupted.
  *
  * Return: a pointer to the cache on success, NULL on failure.
  */
-struct kmem_cache *
-kmem_cache_create_usercopy(const char *name,
-		  unsigned int size, unsigned int align,
-		  slab_flags_t flags,
-		  unsigned int useroffset, unsigned int usersize,
-		  void (*ctor)(void *))
+struct kmem_cache *__kmem_cache_create_args(const char *name,
+					    unsigned int object_size,
+					    struct kmem_cache_args *args,
+					    slab_flags_t flags)
 {
 	struct kmem_cache *s = NULL;
 	const char *cache_name;
@@ -309,7 +291,7 @@ kmem_cache_create_usercopy(const char *name,
 
 	mutex_lock(&slab_mutex);
 
-	err = kmem_cache_sanity_check(name, size);
+	err = kmem_cache_sanity_check(name, object_size);
 	if (err) {
 		goto out_unlock;
 	}
@@ -330,12 +312,14 @@ kmem_cache_create_usercopy(const char *name,
 
 	/* Fail closed on bad usersize of useroffset values. */
 	if (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) ||
-	    WARN_ON(!usersize && useroffset) ||
-	    WARN_ON(size < usersize || size - usersize < useroffset))
-		usersize = useroffset = 0;
-
-	if (!usersize)
-		s = __kmem_cache_alias(name, size, align, flags, ctor);
+	    WARN_ON(!args->usersize && args->useroffset) ||
+	    WARN_ON(object_size < args->usersize ||
+		    object_size - args->usersize < args->useroffset))
+		args->usersize = args->useroffset = 0;
+
+	if (!args->usersize)
+		s = __kmem_cache_alias(name, object_size, args->align, flags,
+				       args->ctor);
 	if (s)
 		goto out_unlock;
 
@@ -345,9 +329,8 @@ kmem_cache_create_usercopy(const char *name,
 		goto out_unlock;
 	}
 
-	s = create_cache(cache_name, size,
-			 calculate_alignment(flags, align, size),
-			 flags, useroffset, usersize, ctor, NULL);
+	args->align = calculate_alignment(flags, args->align, object_size);
+	s = create_cache(cache_name, object_size, args, flags);
 	if (IS_ERR(s)) {
 		err = PTR_ERR(s);
 		kfree_const(cache_name);
@@ -369,41 +352,7 @@ out_unlock:
 	}
 	return s;
 }
-EXPORT_SYMBOL(kmem_cache_create_usercopy);
-
-/**
- * kmem_cache_create - Create a cache.
- * @name: A string which is used in /proc/slabinfo to identify this cache.
- * @size: The size of objects to be created in this cache.
- * @align: The required alignment for the objects.
- * @flags: SLAB flags
- * @ctor: A constructor for the objects.
- *
- * Cannot be called within a interrupt, but can be interrupted.
- * The @ctor is run when new pages are allocated by the cache.
- *
- * The flags are
- *
- * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
- * to catch references to uninitialised memory.
- *
- * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
- * for buffer overruns.
- *
- * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
- * cacheline.  This can be beneficial if you're counting cycles as closely
- * as davem.
- *
- * Return: a pointer to the cache on success, NULL on failure.
- */
-struct kmem_cache *
-kmem_cache_create(const char *name, unsigned int size, unsigned int align,
-		slab_flags_t flags, void (*ctor)(void *))
-{
-	return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
-					  ctor);
-}
-EXPORT_SYMBOL(kmem_cache_create);
+EXPORT_SYMBOL(__kmem_cache_create_args);
 
 static struct kmem_cache *kmem_buckets_cache __ro_after_init;
 
@@ -689,9 +638,7 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
 {
 	int err;
 	unsigned int align = ARCH_KMALLOC_MINALIGN;
-
-	s->name = name;
-	s->size = s->object_size = size;
+	struct kmem_cache_args kmem_args = {};
 
 	/*
 	 * kmalloc caches guarantee alignment of at least the largest
@@ -700,14 +647,14 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
 	 */
 	if (flags & SLAB_KMALLOC)
 		align = max(align, 1U << (ffs(size) - 1));
-	s->align = calculate_alignment(flags, align, size);
+	kmem_args.align = calculate_alignment(flags, align, size);
 
 #ifdef CONFIG_HARDENED_USERCOPY
-	s->useroffset = useroffset;
-	s->usersize = usersize;
+	kmem_args.useroffset = useroffset;
+	kmem_args.usersize = usersize;
 #endif
 
-	err = __kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, name, size, &kmem_args, flags);
 
 	if (err)
 		panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",