[PATCH v4 00/17] slab: add struct kmem_cache_args

[PATCH v4 00/17] slab: add struct kmem_cache_args

[Christian Brauner]

Hey,

This is v4 which allows NULL to be passed in the struct kmem_cache_args
argument of kmem_cache_create() and substitutes default parameters in
this case.

As discussed last week the various kmem_cache_*() functions should be
replaced by a unified function that is based around a struct, with only
the basic parameters passed separately.

Vlastimil already said that he would like to keep core parameters out
of the struct: name, object size, and flags. I personally don't care
much and would not object to moving everything into the struct but
that's a matter of taste and I yield that decision power to the
maintainer.

In the first version I pointed out that the choice of name is somewhat
forced as kmem_cache_create() is taken and the only way to reuse it
would be to replace all users in one go. Or to do a global
sed/kmem_cache_create()/kmem_cache_create2()/g. And then introduce
kmem_cache_setup(). That doesn't strike me as a viable option.

If we really cared about the *_create() suffix then an alternative might
be to do a sed/kmem_cache_setup()/kmem_cache_create()/g after every user
in the kernel is ported. I honestly don't think that's worth it but I
wanted to at least mention it to highlight the fact that this might lead
to a naming compromise.

However, I came up with an alternative using _Generic() to create a
compatibility layer that will call the correct variant of
kmem_cache_create() depending on whether struct kmem_cache_args is
passed or not. That compatibility layer can stay in place until we
updated all calls to be based on struct kmem_cache_args.

From a cursory grep (and not excluding Documentation mentions) we will
have to replace 44 kmem_cache_create_usercopy() calls and about 463
kmem_cache_create() calls which makes for a bit above 500 calls to port
to kmem_cache_setup(). That'll probably be good work for people getting
into kernel development.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
Changes in v4:
- Allow NULL to be passed in the struct kmem_cache_args argument of
  kmem_cache_create() and use default parameters in this case.
- Link to v3: https://lore.kernel.org/r/20240904-work-kmem_cache_args-v3-0-05db2179a8c2@kernel.org

Changes in v3:
- Reworded some commit messages.
- Picked up various RvBs.
- Added two patches to make two functions static inline.
- Link to v2: https://lore.kernel.org/r/20240903-work-kmem_cache_args-v2-0-76f97e9a4560@kernel.org

Changes in v2:
- Remove kmem_cache_setup() and add a compatibility layer built around
  _Generic() so that we can keep the kmem_cache_create() name and type
  switch on the third argument to either call __kmem_cache_create() or
  __kmem_cache_create_args().
- Link to v1: https://lore.kernel.org/r/20240902-work-kmem_cache_args-v1-0-27d05bc05128@kernel.org

---
Christian Brauner (17):
      slab: s/__kmem_cache_create/do_kmem_cache_create/g
      slab: add struct kmem_cache_args
      slab: port kmem_cache_create() to struct kmem_cache_args
      slab: port kmem_cache_create_rcu() to struct kmem_cache_args
      slab: port kmem_cache_create_usercopy() to struct kmem_cache_args
      slab: pass struct kmem_cache_args to create_cache()
      slab: pull kmem_cache_open() into do_kmem_cache_create()
      slab: pass struct kmem_cache_args to do_kmem_cache_create()
      slab: remove rcu_freeptr_offset from struct kmem_cache
      slab: port KMEM_CACHE() to struct kmem_cache_args
      slab: port KMEM_CACHE_USERCOPY() to struct kmem_cache_args
      slab: create kmem_cache_create() compatibility layer
      file: port to struct kmem_cache_args
      slab: remove kmem_cache_create_rcu()
      slab: make kmem_cache_create_usercopy() static inline
      slab: make __kmem_cache_create() static inline
      io_uring: port to struct kmem_cache_args

 fs/file_table.c      |  11 ++-
 include/linux/slab.h | 130 +++++++++++++++++++++++++++------
 io_uring/io_uring.c  |  14 ++--
 mm/slab.h            |   6 +-
 mm/slab_common.c     | 197 +++++++++++----------------------------------------
 mm/slub.c            | 162 +++++++++++++++++++++---------------------
 6 files changed, 250 insertions(+), 270 deletions(-)
---
base-commit: 6e016babce7c845ed015da25c7a097fa3482d95a
change-id: 20240902-work-kmem_cache_args-e9760972c7d4

[PATCH v4 01/17] slab: s/__kmem_cache_create/do_kmem_cache_create/g

[Christian Brauner]

Free up reusing the double-underscore variant for follow-up patches.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab.h        | 2 +-
 mm/slab_common.c | 4 ++--
 mm/slub.c        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index a6051385186e..684bb48c4f39 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -424,7 +424,7 @@ kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller)
 gfp_t kmalloc_fix_flags(gfp_t flags);
 
 /* Functions provided by the slab allocators */
-int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
+int do_kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
 
 void __init kmem_cache_init(void);
 extern void create_boot_cache(struct kmem_cache *, const char *name,
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 95db3702f8d6..91e0e36e4379 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -234,7 +234,7 @@ static struct kmem_cache *create_cache(const char *name,
 	s->useroffset = useroffset;
 	s->usersize = usersize;
 #endif
-	err = __kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, flags);
 	if (err)
 		goto out_free_cache;
 
@@ -778,7 +778,7 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
 	s->usersize = usersize;
 #endif
 
-	err = __kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, flags);
 
 	if (err)
 		panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
diff --git a/mm/slub.c b/mm/slub.c
index 9aa5da1e8e27..23d9d783ff26 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5902,7 +5902,7 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 	return s;
 }
 
-int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
+int do_kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
 {
 	int err;
 

-- 
2.45.2

Re: [PATCH v4 01/17] slab: s/__kmem_cache_create/do_kmem_cache_create/g

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:44AM +0200, Christian Brauner wrote:
> Free up reusing the double-underscore variant for follow-up patches.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

Thanks

[PATCH v4 02/17] slab: add struct kmem_cache_args

[Christian Brauner]

Currently we have multiple kmem_cache_create*() variants that take up to
seven separate parameters with one of the functions having to grow an
eigth parameter in the future to handle both usercopy and a custom
freelist pointer.

Add a struct kmem_cache_args structure and move less common parameters
into it. Core parameters such as name, object size, and flags continue
to be passed separately.

Add a new function __kmem_cache_create_args() that takes a struct
kmem_cache_args pointer and port do_kmem_cache_create_usercopy() over to
it.

In follow-up patches we will port the other kmem_cache_create*()
variants over to it as well.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h | 21 ++++++++++++++++
 mm/slab_common.c     | 67 +++++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 72 insertions(+), 16 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 5b2da2cf31a8..79d8c8bca4a4 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -240,6 +240,27 @@ struct mem_cgroup;
  */
 bool slab_is_available(void);
 
+/**
+ * @align: The required alignment for the objects.
+ * @useroffset: Usercopy region offset
+ * @usersize: Usercopy region size
+ * @freeptr_offset: Custom offset for the free pointer in RCU caches
+ * @use_freeptr_offset: Whether a @freeptr_offset is used
+ * @ctor: A constructor for the objects.
+ */
+struct kmem_cache_args {
+	unsigned int align;
+	unsigned int useroffset;
+	unsigned int usersize;
+	unsigned int freeptr_offset;
+	bool use_freeptr_offset;
+	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 *kmem_cache_create(const char *name, unsigned int size,
 			unsigned int align, slab_flags_t flags,
 			void (*ctor)(void *));
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 91e0e36e4379..0f13c045b8d1 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -248,14 +248,24 @@ static struct kmem_cache *create_cache(const char *name,
 	return ERR_PTR(err);
 }
 
-static struct kmem_cache *
-do_kmem_cache_create_usercopy(const char *name,
-		  unsigned int size, unsigned int freeptr_offset,
-		  unsigned int align, slab_flags_t flags,
-		  unsigned int useroffset, unsigned int usersize,
-		  void (*ctor)(void *))
+/**
+ * __kmem_cache_create_args - Create a kmem cache
+ * @name: A string which is used in /proc/slabinfo to identify this cache.
+ * @object_size: The size of objects to be created in this cache.
+ * @args: 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.
+ *
+ * Return: a pointer to the cache on success, NULL on failure.
+ */
+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;
+	unsigned int freeptr_offset = UINT_MAX;
 	const char *cache_name;
 	int err;
 
@@ -275,7 +285,7 @@ do_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;
 	}
@@ -296,12 +306,14 @@ do_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;
 
@@ -311,9 +323,11 @@ do_kmem_cache_create_usercopy(const char *name,
 		goto out_unlock;
 	}
 
-	s = create_cache(cache_name, size, freeptr_offset,
-			 calculate_alignment(flags, align, size),
-			 flags, useroffset, usersize, ctor);
+	if (args->use_freeptr_offset)
+		freeptr_offset = args->freeptr_offset;
+	s = create_cache(cache_name, object_size, freeptr_offset,
+			 calculate_alignment(flags, args->align, object_size),
+			 flags, args->useroffset, args->usersize, args->ctor);
 	if (IS_ERR(s)) {
 		err = PTR_ERR(s);
 		kfree_const(cache_name);
@@ -335,6 +349,27 @@ do_kmem_cache_create_usercopy(const char *name,
 	}
 	return s;
 }
+EXPORT_SYMBOL(__kmem_cache_create_args);
+
+static struct kmem_cache *
+do_kmem_cache_create_usercopy(const char *name,
+                 unsigned int size, unsigned int freeptr_offset,
+                 unsigned int align, slab_flags_t flags,
+                 unsigned int useroffset, unsigned int usersize,
+                 void (*ctor)(void *))
+{
+	struct kmem_cache_args kmem_args = {
+		.align			= align,
+		.use_freeptr_offset	= freeptr_offset != UINT_MAX,
+		.freeptr_offset		= freeptr_offset,
+		.useroffset		= useroffset,
+		.usersize		= usersize,
+		.ctor			= ctor,
+	};
+
+	return __kmem_cache_create_args(name, size, &kmem_args, flags);
+}
+
 
 /**
  * kmem_cache_create_usercopy - Create a cache with a region suitable

-- 
2.45.2

Re: [PATCH v4 02/17] slab: add struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:45AM +0200, Christian Brauner wrote:
> Currently we have multiple kmem_cache_create*() variants that take up to
> seven separate parameters with one of the functions having to grow an
> eigth parameter in the future to handle both usercopy and a custom
> freelist pointer.
> 
> Add a struct kmem_cache_args structure and move less common parameters
> into it. Core parameters such as name, object size, and flags continue
> to be passed separately.
> 
> Add a new function __kmem_cache_create_args() that takes a struct
> kmem_cache_args pointer and port do_kmem_cache_create_usercopy() over to
> it.
> 
> In follow-up patches we will port the other kmem_cache_create*()
> variants over to it as well.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 03/17] slab: port kmem_cache_create() to struct kmem_cache_args

[Christian Brauner]

Port kmem_cache_create() to struct kmem_cache_args.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab_common.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 0f13c045b8d1..ac0832dac01e 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -439,8 +439,12 @@ struct kmem_cache *
 kmem_cache_create(const char *name, unsigned int size, unsigned int align,
 		slab_flags_t flags, void (*ctor)(void *))
 {
-	return do_kmem_cache_create_usercopy(name, size, UINT_MAX, align, flags,
-					     0, 0, ctor);
+	struct kmem_cache_args kmem_args = {
+		.align	= align,
+		.ctor	= ctor,
+	};
+
+	return __kmem_cache_create_args(name, size, &kmem_args, flags);
 }
 EXPORT_SYMBOL(kmem_cache_create);
 

-- 
2.45.2

Re: [PATCH v4 03/17] slab: port kmem_cache_create() to struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:46AM +0200, Christian Brauner wrote:
> Port kmem_cache_create() to struct kmem_cache_args.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 04/17] slab: port kmem_cache_create_rcu() to struct kmem_cache_args

[Christian Brauner]

Port kmem_cache_create_rcu() to struct kmem_cache_args.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab_common.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index ac0832dac01e..da62ed30f95d 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -481,9 +481,13 @@ struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size,
 					 unsigned int freeptr_offset,
 					 slab_flags_t flags)
 {
-	return do_kmem_cache_create_usercopy(name, size, freeptr_offset, 0,
-					     flags | SLAB_TYPESAFE_BY_RCU, 0, 0,
-					     NULL);
+	struct kmem_cache_args kmem_args = {
+		.freeptr_offset		= freeptr_offset,
+		.use_freeptr_offset	= true,
+	};
+
+	return __kmem_cache_create_args(name, size, &kmem_args,
+					flags | SLAB_TYPESAFE_BY_RCU);
 }
 EXPORT_SYMBOL(kmem_cache_create_rcu);
 

-- 
2.45.2

Re: [PATCH v4 04/17] slab: port kmem_cache_create_rcu() to struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:47AM +0200, Christian Brauner wrote:
> Port kmem_cache_create_rcu() to struct kmem_cache_args.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 05/17] slab: port kmem_cache_create_usercopy() to struct kmem_cache_args

[Christian Brauner]

Port kmem_cache_create_usercopy() to struct kmem_cache_args and remove
the now unused do_kmem_cache_create_usercopy() helper.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab_common.c | 30 ++++++++----------------------
 1 file changed, 8 insertions(+), 22 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index da62ed30f95d..16c36a946135 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -351,26 +351,6 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 }
 EXPORT_SYMBOL(__kmem_cache_create_args);
 
-static struct kmem_cache *
-do_kmem_cache_create_usercopy(const char *name,
-                 unsigned int size, unsigned int freeptr_offset,
-                 unsigned int align, slab_flags_t flags,
-                 unsigned int useroffset, unsigned int usersize,
-                 void (*ctor)(void *))
-{
-	struct kmem_cache_args kmem_args = {
-		.align			= align,
-		.use_freeptr_offset	= freeptr_offset != UINT_MAX,
-		.freeptr_offset		= freeptr_offset,
-		.useroffset		= useroffset,
-		.usersize		= usersize,
-		.ctor			= ctor,
-	};
-
-	return __kmem_cache_create_args(name, size, &kmem_args, flags);
-}
-
-
 /**
  * kmem_cache_create_usercopy - Create a cache with a region suitable
  * for copying to userspace
@@ -405,8 +385,14 @@ kmem_cache_create_usercopy(const char *name, unsigned int size,
 			   unsigned int useroffset, unsigned int usersize,
 			   void (*ctor)(void *))
 {
-	return do_kmem_cache_create_usercopy(name, size, UINT_MAX, align, flags,
-					     useroffset, usersize, ctor);
+	struct kmem_cache_args kmem_args = {
+		.align		= align,
+		.ctor		= ctor,
+		.useroffset	= useroffset,
+		.usersize	= usersize,
+	};
+
+	return __kmem_cache_create_args(name, size, &kmem_args, flags);
 }
 EXPORT_SYMBOL(kmem_cache_create_usercopy);
 

-- 
2.45.2

Re: [PATCH v4 05/17] slab: port kmem_cache_create_usercopy() to struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:48AM +0200, Christian Brauner wrote:
> Port kmem_cache_create_usercopy() to struct kmem_cache_args and remove
> the now unused do_kmem_cache_create_usercopy() helper.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 06/17] slab: pass struct kmem_cache_args to create_cache()

[Christian Brauner]

Pass struct kmem_cache_args to create_cache() so that we can later
simplify further helpers.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab_common.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 16c36a946135..9baa61c9c670 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -202,22 +202,22 @@ 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 freeptr_offset,
-		unsigned int align, slab_flags_t flags,
-		unsigned int useroffset, unsigned int usersize,
-		void (*ctor)(void *))
+				       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 (freeptr_offset != UINT_MAX &&
-	    (freeptr_offset >= object_size || !(flags & SLAB_TYPESAFE_BY_RCU) ||
-	     !IS_ALIGNED(freeptr_offset, sizeof(freeptr_t))))
+	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;
@@ -227,12 +227,15 @@ static struct kmem_cache *create_cache(const char *name,
 
 	s->name = name;
 	s->size = s->object_size = object_size;
-	s->rcu_freeptr_offset = freeptr_offset;
-	s->align = align;
-	s->ctor = ctor;
+	if (args->use_freeptr_offset)
+		s->rcu_freeptr_offset = args->freeptr_offset;
+	else
+		s->rcu_freeptr_offset = UINT_MAX;
+	s->align = args->align;
+	s->ctor = args->ctor;
 #ifdef CONFIG_HARDENED_USERCOPY
-	s->useroffset = useroffset;
-	s->usersize = usersize;
+	s->useroffset = args->useroffset;
+	s->usersize = args->usersize;
 #endif
 	err = do_kmem_cache_create(s, flags);
 	if (err)
@@ -265,7 +268,6 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 					    slab_flags_t flags)
 {
 	struct kmem_cache *s = NULL;
-	unsigned int freeptr_offset = UINT_MAX;
 	const char *cache_name;
 	int err;
 
@@ -323,11 +325,8 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 		goto out_unlock;
 	}
 
-	if (args->use_freeptr_offset)
-		freeptr_offset = args->freeptr_offset;
-	s = create_cache(cache_name, object_size, freeptr_offset,
-			 calculate_alignment(flags, args->align, object_size),
-			 flags, args->useroffset, args->usersize, args->ctor);
+	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);

-- 
2.45.2

Re: [PATCH v4 06/17] slab: pass struct kmem_cache_args to create_cache()

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:49AM +0200, Christian Brauner wrote:
> Pass struct kmem_cache_args to create_cache() so that we can later
> simplify further helpers.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 07/17] slab: pull kmem_cache_open() into do_kmem_cache_create()

[Christian Brauner]

do_kmem_cache_create() is the only caller and we're going to pass down
struct kmem_cache_args in a follow-up patch.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slub.c | 132 +++++++++++++++++++++++++++++---------------------------------
 1 file changed, 62 insertions(+), 70 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 23d9d783ff26..30f4ca6335c7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5290,65 +5290,6 @@ static int calculate_sizes(struct kmem_cache *s)
 	return !!oo_objects(s->oo);
 }
 
-static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
-{
-	s->flags = kmem_cache_flags(flags, s->name);
-#ifdef CONFIG_SLAB_FREELIST_HARDENED
-	s->random = get_random_long();
-#endif
-
-	if (!calculate_sizes(s))
-		goto error;
-	if (disable_higher_order_debug) {
-		/*
-		 * Disable debugging flags that store metadata if the min slab
-		 * order increased.
-		 */
-		if (get_order(s->size) > get_order(s->object_size)) {
-			s->flags &= ~DEBUG_METADATA_FLAGS;
-			s->offset = 0;
-			if (!calculate_sizes(s))
-				goto error;
-		}
-	}
-
-#ifdef system_has_freelist_aba
-	if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
-		/* Enable fast mode */
-		s->flags |= __CMPXCHG_DOUBLE;
-	}
-#endif
-
-	/*
-	 * The larger the object size is, the more slabs we want on the partial
-	 * list to avoid pounding the page allocator excessively.
-	 */
-	s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
-	s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
-
-	set_cpu_partial(s);
-
-#ifdef CONFIG_NUMA
-	s->remote_node_defrag_ratio = 1000;
-#endif
-
-	/* Initialize the pre-computed randomized freelist if slab is up */
-	if (slab_state >= UP) {
-		if (init_cache_random_seq(s))
-			goto error;
-	}
-
-	if (!init_kmem_cache_nodes(s))
-		goto error;
-
-	if (alloc_kmem_cache_cpus(s))
-		return 0;
-
-error:
-	__kmem_cache_release(s);
-	return -EINVAL;
-}
-
 static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
 			      const char *text)
 {
@@ -5904,26 +5845,77 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 
 int do_kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
 {
-	int err;
+	int err = -EINVAL;
 
-	err = kmem_cache_open(s, flags);
-	if (err)
-		return err;
+	s->flags = kmem_cache_flags(flags, s->name);
+#ifdef CONFIG_SLAB_FREELIST_HARDENED
+	s->random = get_random_long();
+#endif
+
+	if (!calculate_sizes(s))
+		goto out;
+	if (disable_higher_order_debug) {
+		/*
+		 * Disable debugging flags that store metadata if the min slab
+		 * order increased.
+		 */
+		if (get_order(s->size) > get_order(s->object_size)) {
+			s->flags &= ~DEBUG_METADATA_FLAGS;
+			s->offset = 0;
+			if (!calculate_sizes(s))
+				goto out;
+		}
+	}
+
+#ifdef system_has_freelist_aba
+	if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
+		/* Enable fast mode */
+		s->flags |= __CMPXCHG_DOUBLE;
+	}
+#endif
+
+	/*
+	 * The larger the object size is, the more slabs we want on the partial
+	 * list to avoid pounding the page allocator excessively.
+	 */
+	s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
+	s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
+
+	set_cpu_partial(s);
+
+#ifdef CONFIG_NUMA
+	s->remote_node_defrag_ratio = 1000;
+#endif
+
+	/* Initialize the pre-computed randomized freelist if slab is up */
+	if (slab_state >= UP) {
+		if (init_cache_random_seq(s))
+			goto out;
+	}
+
+	if (!init_kmem_cache_nodes(s))
+		goto out;
+
+	if (!alloc_kmem_cache_cpus(s))
+		goto out;
 
 	/* Mutex is not taken during early boot */
-	if (slab_state <= UP)
-		return 0;
+	if (slab_state <= UP) {
+		err = 0;
+		goto out;
+	}
 
 	err = sysfs_slab_add(s);
-	if (err) {
-		__kmem_cache_release(s);
-		return err;
-	}
+	if (err)
+		goto out;
 
 	if (s->flags & SLAB_STORE_USER)
 		debugfs_slab_add(s);
 
-	return 0;
+out:
+	if (err)
+		__kmem_cache_release(s);
+	return err;
 }
 
 #ifdef SLAB_SUPPORTS_SYSFS

-- 
2.45.2

Re: [PATCH v4 07/17] slab: pull kmem_cache_open() into do_kmem_cache_create()

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:50AM +0200, Christian Brauner wrote:
> do_kmem_cache_create() is the only caller and we're going to pass down
> struct kmem_cache_args in a follow-up patch.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 08/17] slab: pass struct kmem_cache_args to do_kmem_cache_create()

[Christian Brauner]

and initialize most things in do_kmem_cache_create(). In a follow-up
patch we'll remove rcu_freeptr_offset from struct kmem_cache.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab.h        |  4 +++-
 mm/slab_common.c | 27 ++++++---------------------
 mm/slub.c        | 17 ++++++++++++++++-
 3 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index 684bb48c4f39..c7a4e0fc3cf1 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -424,7 +424,9 @@ kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller)
 gfp_t kmalloc_fix_flags(gfp_t flags);
 
 /* Functions provided by the slab allocators */
-int do_kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
+int do_kmem_cache_create(struct kmem_cache *s, const char *name,
+			 unsigned int size, struct kmem_cache_args *args,
+			 slab_flags_t flags);
 
 void __init kmem_cache_init(void);
 extern void create_boot_cache(struct kmem_cache *, const char *name,
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 9baa61c9c670..19ae3dd6e36f 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -224,20 +224,7 @@ static struct kmem_cache *create_cache(const char *name,
 	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
 	if (!s)
 		goto out;
-
-	s->name = name;
-	s->size = s->object_size = object_size;
-	if (args->use_freeptr_offset)
-		s->rcu_freeptr_offset = args->freeptr_offset;
-	else
-		s->rcu_freeptr_offset = UINT_MAX;
-	s->align = args->align;
-	s->ctor = args->ctor;
-#ifdef CONFIG_HARDENED_USERCOPY
-	s->useroffset = args->useroffset;
-	s->usersize = args->usersize;
-#endif
-	err = do_kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, name, object_size, args, flags);
 	if (err)
 		goto out_free_cache;
 
@@ -788,9 +775,7 @@ 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
@@ -799,14 +784,14 @@ 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 = do_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",
diff --git a/mm/slub.c b/mm/slub.c
index 30f4ca6335c7..4719b60215b8 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5843,14 +5843,29 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 	return s;
 }
 
-int do_kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
+int do_kmem_cache_create(struct kmem_cache *s, const char *name,
+			 unsigned int size, struct kmem_cache_args *args,
+			 slab_flags_t flags)
 {
 	int err = -EINVAL;
 
+	s->name = name;
+	s->size = s->object_size = size;
+
 	s->flags = kmem_cache_flags(flags, s->name);
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
 	s->random = get_random_long();
 #endif
+	if (args->use_freeptr_offset)
+		s->rcu_freeptr_offset = args->freeptr_offset;
+	else
+		s->rcu_freeptr_offset = UINT_MAX;
+	s->align = args->align;
+	s->ctor = args->ctor;
+#ifdef CONFIG_HARDENED_USERCOPY
+	s->useroffset = args->useroffset;
+	s->usersize = args->usersize;
+#endif
 
 	if (!calculate_sizes(s))
 		goto out;

-- 
2.45.2

Re: [PATCH v4 08/17] slab: pass struct kmem_cache_args to do_kmem_cache_create()

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:51AM +0200, Christian Brauner wrote:
> and initialize most things in do_kmem_cache_create(). In a follow-up
> patch we'll remove rcu_freeptr_offset from struct kmem_cache.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 09/17] slab: remove rcu_freeptr_offset from struct kmem_cache

[Christian Brauner]

Pass down struct kmem_cache_args to calculate_sizes() so we can use
args->{use}_freeptr_offset directly. This allows us to remove
->rcu_freeptr_offset from struct kmem_cache.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 mm/slab.h |  2 --
 mm/slub.c | 25 +++++++------------------
 2 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index c7a4e0fc3cf1..36ac38e21fcb 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -261,8 +261,6 @@ struct kmem_cache {
 	unsigned int object_size;	/* Object size without metadata */
 	struct reciprocal_value reciprocal_size;
 	unsigned int offset;		/* Free pointer offset */
-	/* Specific free pointer requested (if not UINT_MAX) */
-	unsigned int rcu_freeptr_offset;
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 	/* Number of per cpu partial objects to keep around */
 	unsigned int cpu_partial;
diff --git a/mm/slub.c b/mm/slub.c
index 4719b60215b8..a23c7036cd61 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3916,8 +3916,7 @@ static void *__slab_alloc_node(struct kmem_cache *s,
  * If the object has been wiped upon free, make sure it's fully initialized by
  * zeroing out freelist pointer.
  *
- * Note that we also wipe custom freelist pointers specified via
- * s->rcu_freeptr_offset.
+ * Note that we also wipe custom freelist pointers.
  */
 static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
 						   void *obj)
@@ -5141,17 +5140,11 @@ static void set_cpu_partial(struct kmem_cache *s)
 #endif
 }
 
-/* Was a valid freeptr offset requested? */
-static inline bool has_freeptr_offset(const struct kmem_cache *s)
-{
-	return s->rcu_freeptr_offset != UINT_MAX;
-}
-
 /*
  * calculate_sizes() determines the order and the distribution of data within
  * a slab object.
  */
-static int calculate_sizes(struct kmem_cache *s)
+static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s)
 {
 	slab_flags_t flags = s->flags;
 	unsigned int size = s->object_size;
@@ -5192,7 +5185,7 @@ static int calculate_sizes(struct kmem_cache *s)
 	 */
 	s->inuse = size;
 
-	if (((flags & SLAB_TYPESAFE_BY_RCU) && !has_freeptr_offset(s)) ||
+	if (((flags & SLAB_TYPESAFE_BY_RCU) && !args->use_freeptr_offset) ||
 	    (flags & SLAB_POISON) || s->ctor ||
 	    ((flags & SLAB_RED_ZONE) &&
 	     (s->object_size < sizeof(void *) || slub_debug_orig_size(s)))) {
@@ -5214,8 +5207,8 @@ static int calculate_sizes(struct kmem_cache *s)
 		 */
 		s->offset = size;
 		size += sizeof(void *);
-	} else if ((flags & SLAB_TYPESAFE_BY_RCU) && has_freeptr_offset(s)) {
-		s->offset = s->rcu_freeptr_offset;
+	} else if ((flags & SLAB_TYPESAFE_BY_RCU) && args->use_freeptr_offset) {
+		s->offset = args->freeptr_offset;
 	} else {
 		/*
 		 * Store freelist pointer near middle of object to keep
@@ -5856,10 +5849,6 @@ int do_kmem_cache_create(struct kmem_cache *s, const char *name,
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
 	s->random = get_random_long();
 #endif
-	if (args->use_freeptr_offset)
-		s->rcu_freeptr_offset = args->freeptr_offset;
-	else
-		s->rcu_freeptr_offset = UINT_MAX;
 	s->align = args->align;
 	s->ctor = args->ctor;
 #ifdef CONFIG_HARDENED_USERCOPY
@@ -5867,7 +5856,7 @@ int do_kmem_cache_create(struct kmem_cache *s, const char *name,
 	s->usersize = args->usersize;
 #endif
 
-	if (!calculate_sizes(s))
+	if (!calculate_sizes(args, s))
 		goto out;
 	if (disable_higher_order_debug) {
 		/*
@@ -5877,7 +5866,7 @@ int do_kmem_cache_create(struct kmem_cache *s, const char *name,
 		if (get_order(s->size) > get_order(s->object_size)) {
 			s->flags &= ~DEBUG_METADATA_FLAGS;
 			s->offset = 0;
-			if (!calculate_sizes(s))
+			if (!calculate_sizes(args, s))
 				goto out;
 		}
 	}

-- 
2.45.2

Re: [PATCH v4 09/17] slab: remove rcu_freeptr_offset from struct kmem_cache

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:52AM +0200, Christian Brauner wrote:
> Pass down struct kmem_cache_args to calculate_sizes() so we can use
> args->{use}_freeptr_offset directly. This allows us to remove
> ->rcu_freeptr_offset from struct kmem_cache.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 10/17] slab: port KMEM_CACHE() to struct kmem_cache_args

[Christian Brauner]

Make KMEM_CACHE() use struct kmem_cache_args.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 79d8c8bca4a4..97117a2fcf34 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -283,9 +283,11 @@ int kmem_cache_shrink(struct kmem_cache *s);
  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
  * then the objects will be properly aligned in SMP configurations.
  */
-#define KMEM_CACHE(__struct, __flags)					\
-		kmem_cache_create(#__struct, sizeof(struct __struct),	\
-			__alignof__(struct __struct), (__flags), NULL)
+#define KMEM_CACHE(__struct, __flags)                                   \
+	__kmem_cache_create_args(#__struct, sizeof(struct __struct),    \
+			&(struct kmem_cache_args) {			\
+				.align	= __alignof__(struct __struct), \
+			}, (__flags))
 
 /*
  * To whitelist a single field for copying to/from usercopy, use this

-- 
2.45.2

Re: [PATCH v4 10/17] slab: port KMEM_CACHE() to struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:53AM +0200, Christian Brauner wrote:
> Make KMEM_CACHE() use struct kmem_cache_args.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 11/17] slab: port KMEM_CACHE_USERCOPY() to struct kmem_cache_args

[Christian Brauner]

Make KMEM_CACHE_USERCOPY() use struct kmem_cache_args.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 97117a2fcf34..cb264dded324 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -293,12 +293,13 @@ int kmem_cache_shrink(struct kmem_cache *s);
  * To whitelist a single field for copying to/from usercopy, use this
  * macro instead for KMEM_CACHE() above.
  */
-#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)			\
-		kmem_cache_create_usercopy(#__struct,			\
-			sizeof(struct __struct),			\
-			__alignof__(struct __struct), (__flags),	\
-			offsetof(struct __struct, __field),		\
-			sizeof_field(struct __struct, __field), NULL)
+#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)						\
+	__kmem_cache_create_args(#__struct, sizeof(struct __struct),				\
+			&(struct kmem_cache_args) {						\
+				.align		= __alignof__(struct __struct),			\
+				.useroffset	= offsetof(struct __struct, __field),		\
+				.usersize	= sizeof_field(struct __struct, __field),	\
+			}, (__flags))
 
 /*
  * Common kmalloc functions provided by all allocators

-- 
2.45.2

Re: [PATCH v4 11/17] slab: port KMEM_CACHE_USERCOPY() to struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:54AM +0200, Christian Brauner wrote:
> Make KMEM_CACHE_USERCOPY() use struct kmem_cache_args.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 12/17] slab: create kmem_cache_create() compatibility layer

[Christian Brauner]

Use _Generic() to create a compatibility layer that type switches on the
third argument to either call __kmem_cache_create() or
__kmem_cache_create_args(). If NULL is passed for the struct
kmem_cache_args argument use default args making porting for callers
that don't care about additional arguments easy.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h | 29 ++++++++++++++++++++++++++---
 mm/slab_common.c     | 10 +++++-----
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index cb264dded324..f74ceb788ac1 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -261,9 +261,10 @@ 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 *kmem_cache_create(const char *name, unsigned int size,
-			unsigned int align, slab_flags_t flags,
-			void (*ctor)(void *));
+
+struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
+				       unsigned int align, slab_flags_t flags,
+				       void (*ctor)(void *));
 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 			unsigned int size, unsigned int align,
 			slab_flags_t flags,
@@ -272,6 +273,28 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size,
 					 unsigned int freeptr_offset,
 					 slab_flags_t flags);
+
+/* If NULL is passed for @args, use this variant with default arguments. */
+static inline struct kmem_cache *
+__kmem_cache_default_args(const char *name, unsigned int size,
+			  struct kmem_cache_args *args,
+			  slab_flags_t flags)
+{
+	struct kmem_cache_args kmem_default_args = {};
+
+	/* Make sure we don't get passed garbage. */
+	if (WARN_ON_ONCE(args))
+		return NULL;
+
+	return __kmem_cache_create_args(name, size, &kmem_default_args, flags);
+}
+
+#define kmem_cache_create(__name, __object_size, __args, ...)           \
+	_Generic((__args),                                              \
+		struct kmem_cache_args *: __kmem_cache_create_args,	\
+		void *: __kmem_cache_default_args,			\
+		default: __kmem_cache_create)(__name, __object_size, __args, __VA_ARGS__)
+
 void kmem_cache_destroy(struct kmem_cache *s);
 int kmem_cache_shrink(struct kmem_cache *s);
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 19ae3dd6e36f..418459927670 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -383,7 +383,7 @@ kmem_cache_create_usercopy(const char *name, unsigned int size,
 EXPORT_SYMBOL(kmem_cache_create_usercopy);
 
 /**
- * kmem_cache_create - Create a cache.
+ * __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.
@@ -407,9 +407,9 @@ EXPORT_SYMBOL(kmem_cache_create_usercopy);
  *
  * 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 *))
+struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
+				       unsigned int align, slab_flags_t flags,
+				       void (*ctor)(void *))
 {
 	struct kmem_cache_args kmem_args = {
 		.align	= align,
@@ -418,7 +418,7 @@ kmem_cache_create(const char *name, unsigned int size, unsigned int align,
 
 	return __kmem_cache_create_args(name, size, &kmem_args, flags);
 }
-EXPORT_SYMBOL(kmem_cache_create);
+EXPORT_SYMBOL(__kmem_cache_create);
 
 /**
  * kmem_cache_create_rcu - Create a SLAB_TYPESAFE_BY_RCU cache.

-- 
2.45.2

Re: [PATCH v4 12/17] slab: create kmem_cache_create() compatibility layer

[Mike Rapoport]

On Thu, Sep 05, 2024 at 09:56:55AM +0200, Christian Brauner wrote:
> Use _Generic() to create a compatibility layer that type switches on the
> third argument to either call __kmem_cache_create() or
> __kmem_cache_create_args(). If NULL is passed for the struct
> kmem_cache_args argument use default args making porting for callers
> that don't care about additional arguments easy.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  include/linux/slab.h | 29 ++++++++++++++++++++++++++---
>  mm/slab_common.c     | 10 +++++-----
>  2 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index cb264dded324..f74ceb788ac1 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -261,9 +261,10 @@ 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 *kmem_cache_create(const char *name, unsigned int size,
> -			unsigned int align, slab_flags_t flags,
> -			void (*ctor)(void *));
> +
> +struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
> +				       unsigned int align, slab_flags_t flags,
> +				       void (*ctor)(void *));
>  struct kmem_cache *kmem_cache_create_usercopy(const char *name,
>  			unsigned int size, unsigned int align,
>  			slab_flags_t flags,
> @@ -272,6 +273,28 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
>  struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size,
>  					 unsigned int freeptr_offset,
>  					 slab_flags_t flags);
> +
> +/* If NULL is passed for @args, use this variant with default arguments. */
> +static inline struct kmem_cache *
> +__kmem_cache_default_args(const char *name, unsigned int size,
> +			  struct kmem_cache_args *args,
> +			  slab_flags_t flags)
> +{
> +	struct kmem_cache_args kmem_default_args = {};
> +
> +	/* Make sure we don't get passed garbage. */
> +	if (WARN_ON_ONCE(args))
> +		return NULL;
> +
> +	return __kmem_cache_create_args(name, size, &kmem_default_args, flags);
> +}
> +
> +#define kmem_cache_create(__name, __object_size, __args, ...)           \
> +	_Generic((__args),                                              \
> +		struct kmem_cache_args *: __kmem_cache_create_args,	\
> +		void *: __kmem_cache_default_args,			\
> +		default: __kmem_cache_create)(__name, __object_size, __args, __VA_ARGS__)
> +
>  void kmem_cache_destroy(struct kmem_cache *s);
>  int kmem_cache_shrink(struct kmem_cache *s);
>  
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 19ae3dd6e36f..418459927670 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -383,7 +383,7 @@ kmem_cache_create_usercopy(const char *name, unsigned int size,
>  EXPORT_SYMBOL(kmem_cache_create_usercopy);
>  
>  /**
> - * kmem_cache_create - Create a cache.
> + * __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.
> @@ -407,9 +407,9 @@ EXPORT_SYMBOL(kmem_cache_create_usercopy);
>   *
>   * 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 *))
> +struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
> +				       unsigned int align, slab_flags_t flags,
> +				       void (*ctor)(void *))
>  {
>  	struct kmem_cache_args kmem_args = {
>  		.align	= align,
> @@ -418,7 +418,7 @@ kmem_cache_create(const char *name, unsigned int size, unsigned int align,
>  
>  	return __kmem_cache_create_args(name, size, &kmem_args, flags);
>  }
> -EXPORT_SYMBOL(kmem_cache_create);
> +EXPORT_SYMBOL(__kmem_cache_create);
>  
>  /**
>   * kmem_cache_create_rcu - Create a SLAB_TYPESAFE_BY_RCU cache.
> 
> -- 
> 2.45.2
> 

-- 
Sincerely yours,
Mike.

Re: [PATCH v4 12/17] slab: create kmem_cache_create() compatibility layer

[Vlastimil Babka]

On 9/5/24 9:56 AM, Christian Brauner wrote:
> Use _Generic() to create a compatibility layer that type switches on the
> third argument to either call __kmem_cache_create() or
> __kmem_cache_create_args(). If NULL is passed for the struct
> kmem_cache_args argument use default args making porting for callers
> that don't care about additional arguments easy.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  include/linux/slab.h | 29 ++++++++++++++++++++++++++---
>  mm/slab_common.c     | 10 +++++-----
>  2 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index cb264dded324..f74ceb788ac1 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -261,9 +261,10 @@ 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 *kmem_cache_create(const char *name, unsigned int size,
> -			unsigned int align, slab_flags_t flags,
> -			void (*ctor)(void *));
> +
> +struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
> +				       unsigned int align, slab_flags_t flags,
> +				       void (*ctor)(void *));
>  struct kmem_cache *kmem_cache_create_usercopy(const char *name,
>  			unsigned int size, unsigned int align,
>  			slab_flags_t flags,
> @@ -272,6 +273,28 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
>  struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size,
>  					 unsigned int freeptr_offset,
>  					 slab_flags_t flags);
> +
> +/* If NULL is passed for @args, use this variant with default arguments. */
> +static inline struct kmem_cache *
> +__kmem_cache_default_args(const char *name, unsigned int size,
> +			  struct kmem_cache_args *args,
> +			  slab_flags_t flags)
> +{
> +	struct kmem_cache_args kmem_default_args = {};
> +
> +	/* Make sure we don't get passed garbage. */
> +	if (WARN_ON_ONCE(args))
> +		return NULL;

I'm changing to return ERR_PTR(-EINVAL); locally
although it's not too important

> +
> +	return __kmem_cache_create_args(name, size, &kmem_default_args, flags);
> +}
> +
> +#define kmem_cache_create(__name, __object_size, __args, ...)           \
> +	_Generic((__args),                                              \
> +		struct kmem_cache_args *: __kmem_cache_create_args,	\
> +		void *: __kmem_cache_default_args,			\
> +		default: __kmem_cache_create)(__name, __object_size, __args, __VA_ARGS__)
> +
>  void kmem_cache_destroy(struct kmem_cache *s);
>  int kmem_cache_shrink(struct kmem_cache *s);
>  
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 19ae3dd6e36f..418459927670 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -383,7 +383,7 @@ kmem_cache_create_usercopy(const char *name, unsigned int size,
>  EXPORT_SYMBOL(kmem_cache_create_usercopy);
>  
>  /**
> - * kmem_cache_create - Create a cache.
> + * __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.
> @@ -407,9 +407,9 @@ EXPORT_SYMBOL(kmem_cache_create_usercopy);
>   *
>   * 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 *))
> +struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
> +				       unsigned int align, slab_flags_t flags,
> +				       void (*ctor)(void *))
>  {
>  	struct kmem_cache_args kmem_args = {
>  		.align	= align,
> @@ -418,7 +418,7 @@ kmem_cache_create(const char *name, unsigned int size, unsigned int align,
>  
>  	return __kmem_cache_create_args(name, size, &kmem_args, flags);
>  }
> -EXPORT_SYMBOL(kmem_cache_create);
> +EXPORT_SYMBOL(__kmem_cache_create);
>  
>  /**
>   * kmem_cache_create_rcu - Create a SLAB_TYPESAFE_BY_RCU cache.
> 

Re: [PATCH v4 12/17] slab: create kmem_cache_create() compatibility layer

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:55AM +0200, Christian Brauner wrote:
> Use _Generic() to create a compatibility layer that type switches on the
> third argument to either call __kmem_cache_create() or
> __kmem_cache_create_args(). If NULL is passed for the struct
> kmem_cache_args argument use default args making porting for callers
> that don't care about additional arguments easy.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 13/17] file: port to struct kmem_cache_args

[Christian Brauner]

Port filp_cache to struct kmem_cache_args.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 fs/file_table.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 3ef558f27a1c..861c03608e83 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -511,9 +511,14 @@ EXPORT_SYMBOL(__fput_sync);
 
 void __init files_init(void)
 {
-	filp_cachep = kmem_cache_create_rcu("filp", sizeof(struct file),
-				offsetof(struct file, f_freeptr),
-				SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);
+	struct kmem_cache_args args = {
+		.use_freeptr_offset = true,
+		.freeptr_offset = offsetof(struct file, f_freeptr),
+	};
+
+	filp_cachep = kmem_cache_create("filp", sizeof(struct file), &args,
+				SLAB_HWCACHE_ALIGN | SLAB_PANIC |
+				SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU);
 	percpu_counter_init(&nr_files, 0, GFP_KERNEL);
 }
 

-- 
2.45.2

Re: [PATCH v4 13/17] file: port to struct kmem_cache_args

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:56AM +0200, Christian Brauner wrote:
> Port filp_cache to struct kmem_cache_args.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 14/17] slab: remove kmem_cache_create_rcu()

[Christian Brauner]

Now that we have ported all users of kmem_cache_create_rcu() to struct
kmem_cache_args the function is unused and can be removed.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h |  3 ---
 mm/slab_common.c     | 43 -------------------------------------------
 2 files changed, 46 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index f74ceb788ac1..8246f9b28f43 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -270,9 +270,6 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 			slab_flags_t flags,
 			unsigned int useroffset, unsigned int usersize,
 			void (*ctor)(void *));
-struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size,
-					 unsigned int freeptr_offset,
-					 slab_flags_t flags);
 
 /* If NULL is passed for @args, use this variant with default arguments. */
 static inline struct kmem_cache *
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 418459927670..9133b9fafcb1 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -420,49 +420,6 @@ struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
 }
 EXPORT_SYMBOL(__kmem_cache_create);
 
-/**
- * kmem_cache_create_rcu - Create a SLAB_TYPESAFE_BY_RCU 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.
- * @freeptr_offset: The offset into the memory to the free pointer
- * @flags: SLAB flags
- *
- * Cannot be called within an interrupt, but can be interrupted.
- *
- * See kmem_cache_create() for an explanation of possible @flags.
- *
- * By default SLAB_TYPESAFE_BY_RCU caches place the free pointer outside
- * of the object. This might cause the object to grow in size. Callers
- * that have a reason to avoid this can specify a custom free pointer
- * offset in their struct where the free pointer will be placed.
- *
- * Note that placing the free pointer inside the object requires the
- * caller to ensure that no fields are invalidated that are required to
- * guard against object recycling (See SLAB_TYPESAFE_BY_RCU for
- * details.).
- *
- * Using zero as a value for @freeptr_offset is valid. To request no
- * offset UINT_MAX must be specified.
- *
- * Note that @ctor isn't supported with custom free pointers as a @ctor
- * requires an external free pointer.
- *
- * Return: a pointer to the cache on success, NULL on failure.
- */
-struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size,
-					 unsigned int freeptr_offset,
-					 slab_flags_t flags)
-{
-	struct kmem_cache_args kmem_args = {
-		.freeptr_offset		= freeptr_offset,
-		.use_freeptr_offset	= true,
-	};
-
-	return __kmem_cache_create_args(name, size, &kmem_args,
-					flags | SLAB_TYPESAFE_BY_RCU);
-}
-EXPORT_SYMBOL(kmem_cache_create_rcu);
-
 static struct kmem_cache *kmem_buckets_cache __ro_after_init;
 
 /**

-- 
2.45.2

Re: [PATCH v4 14/17] slab: remove kmem_cache_create_rcu()

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:57AM +0200, Christian Brauner wrote:
> Now that we have ported all users of kmem_cache_create_rcu() to struct
> kmem_cache_args the function is unused and can be removed.
> 
> Reviewed-by: Kees Cook <kees@kernel.org>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 15/17] slab: make kmem_cache_create_usercopy() static inline

[Christian Brauner]

Make kmem_cache_create_usercopy() a static inline function.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
 mm/slab_common.c     | 45 ---------------------------------------------
 2 files changed, 44 insertions(+), 50 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 8246f9b28f43..d744397aa46f 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -265,11 +265,50 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
 				       unsigned int align, slab_flags_t flags,
 				       void (*ctor)(void *));
-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 *));
+
+/**
+ * kmem_cache_create_usercopy - Create a cache with a region suitable
+ * for copying to userspace
+ * @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.
+ *
+ * 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.
+ */
+static inline 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_args kmem_args = {
+		.align		= align,
+		.ctor		= ctor,
+		.useroffset	= useroffset,
+		.usersize	= usersize,
+	};
+
+	return __kmem_cache_create_args(name, size, &kmem_args, flags);
+}
 
 /* If NULL is passed for @args, use this variant with default arguments. */
 static inline struct kmem_cache *
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 9133b9fafcb1..3477a3918afd 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -337,51 +337,6 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 }
 EXPORT_SYMBOL(__kmem_cache_create_args);
 
-/**
- * kmem_cache_create_usercopy - Create a cache with a region suitable
- * for copying to userspace
- * @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.
- *
- * 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_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_args kmem_args = {
-		.align		= align,
-		.ctor		= ctor,
-		.useroffset	= useroffset,
-		.usersize	= usersize,
-	};
-
-	return __kmem_cache_create_args(name, size, &kmem_args, flags);
-}
-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.

-- 
2.45.2

Re: [PATCH v4 15/17] slab: make kmem_cache_create_usercopy() static inline

[Mike Rapoport]

On Thu, Sep 05, 2024 at 09:56:58AM +0200, Christian Brauner wrote:
> Make kmem_cache_create_usercopy() a static inline function.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  include/linux/slab.h | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
>  mm/slab_common.c     | 45 ---------------------------------------------
>  2 files changed, 44 insertions(+), 50 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 8246f9b28f43..d744397aa46f 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -265,11 +265,50 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
>  struct kmem_cache *__kmem_cache_create(const char *name, unsigned int size,
>  				       unsigned int align, slab_flags_t flags,
>  				       void (*ctor)(void *));
> -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 *));
> +
> +/**
> + * kmem_cache_create_usercopy - Create a cache with a region suitable
> + * for copying to userspace
> + * @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.
> + *
> + * 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.
> + */
> +static inline 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_args kmem_args = {
> +		.align		= align,
> +		.ctor		= ctor,
> +		.useroffset	= useroffset,
> +		.usersize	= usersize,
> +	};
> +
> +	return __kmem_cache_create_args(name, size, &kmem_args, flags);
> +}
>  
>  /* If NULL is passed for @args, use this variant with default arguments. */
>  static inline struct kmem_cache *
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 9133b9fafcb1..3477a3918afd 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -337,51 +337,6 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
>  }
>  EXPORT_SYMBOL(__kmem_cache_create_args);
>  
> -/**
> - * kmem_cache_create_usercopy - Create a cache with a region suitable
> - * for copying to userspace
> - * @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.
> - *
> - * 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_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_args kmem_args = {
> -		.align		= align,
> -		.ctor		= ctor,
> -		.useroffset	= useroffset,
> -		.usersize	= usersize,
> -	};
> -
> -	return __kmem_cache_create_args(name, size, &kmem_args, flags);
> -}
> -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.
> 
> -- 
> 2.45.2
> 

-- 
Sincerely yours,
Mike.

Re: [PATCH v4 15/17] slab: make kmem_cache_create_usercopy() static inline

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:58AM +0200, Christian Brauner wrote:
> Make kmem_cache_create_usercopy() a static inline function.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH v4 16/17] slab: make __kmem_cache_create() static inline

[Christian Brauner]

Make __kmem_cache_create() a static inline function.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/linux/slab.h | 13 ++++++++++---
 mm/slab_common.c     | 38 --------------------------------------
 2 files changed, 10 insertions(+), 41 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index d744397aa46f..597f6913cc0f 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -261,10 +261,17 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 					    unsigned int object_size,
 					    struct kmem_cache_args *args,
 					    slab_flags_t flags);
+static inline struct kmem_cache *
+__kmem_cache_create(const char *name, unsigned int size, unsigned int align,
+		    slab_flags_t flags, void (*ctor)(void *))
+{
+	struct kmem_cache_args kmem_args = {
+		.align	= align,
+		.ctor	= ctor,
+	};
 
-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_args(name, size, &kmem_args, flags);
+}
 
 /**
  * kmem_cache_create_usercopy - Create a cache with a region suitable
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 3477a3918afd..30000dcf0736 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -337,44 +337,6 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
 }
 EXPORT_SYMBOL(__kmem_cache_create_args);
 
-/**
- * __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 *))
-{
-	struct kmem_cache_args kmem_args = {
-		.align	= align,
-		.ctor	= ctor,
-	};
-
-	return __kmem_cache_create_args(name, size, &kmem_args, flags);
-}
-EXPORT_SYMBOL(__kmem_cache_create);
-
 static struct kmem_cache *kmem_buckets_cache __ro_after_init;
 
 /**

-- 
2.45.2

Re: [PATCH v4 16/17] slab: make __kmem_cache_create() static inline

[Mike Rapoport]

On Thu, Sep 05, 2024 at 09:56:59AM +0200, Christian Brauner wrote:
> Make __kmem_cache_create() a static inline function.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  include/linux/slab.h | 13 ++++++++++---
>  mm/slab_common.c     | 38 --------------------------------------
>  2 files changed, 10 insertions(+), 41 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index d744397aa46f..597f6913cc0f 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -261,10 +261,17 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
>  					    unsigned int object_size,
>  					    struct kmem_cache_args *args,
>  					    slab_flags_t flags);
> +static inline struct kmem_cache *
> +__kmem_cache_create(const char *name, unsigned int size, unsigned int align,
> +		    slab_flags_t flags, void (*ctor)(void *))
> +{
> +	struct kmem_cache_args kmem_args = {
> +		.align	= align,
> +		.ctor	= ctor,
> +	};
>  
> -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_args(name, size, &kmem_args, flags);
> +}
>  
>  /**
>   * kmem_cache_create_usercopy - Create a cache with a region suitable
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 3477a3918afd..30000dcf0736 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -337,44 +337,6 @@ struct kmem_cache *__kmem_cache_create_args(const char *name,
>  }
>  EXPORT_SYMBOL(__kmem_cache_create_args);
>  
> -/**
> - * __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 *))
> -{
> -	struct kmem_cache_args kmem_args = {
> -		.align	= align,
> -		.ctor	= ctor,
> -	};
> -
> -	return __kmem_cache_create_args(name, size, &kmem_args, flags);
> -}
> -EXPORT_SYMBOL(__kmem_cache_create);
> -
>  static struct kmem_cache *kmem_buckets_cache __ro_after_init;
>  
>  /**
> 
> -- 
> 2.45.2
> 

-- 
Sincerely yours,
Mike.

Re: [PATCH v4 16/17] slab: make __kmem_cache_create() static inline

[Roman Gushchin]

On Thu, Sep 05, 2024 at 09:56:59AM +0200, Christian Brauner wrote:
> Make __kmem_cache_create() a static inline function.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

Nice series, thank you!

[PATCH v4 17/17] io_uring: port to struct kmem_cache_args

[Christian Brauner]

Port req_cachep to struct kmem_cache_args.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 io_uring/io_uring.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 3942db160f18..d9d721d1424e 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3638,6 +3638,11 @@ SYSCALL_DEFINE2(io_uring_setup, u32, entries,
 
 static int __init io_uring_init(void)
 {
+	struct kmem_cache_args kmem_args = {
+		.useroffset = offsetof(struct io_kiocb, cmd.data),
+		.usersize = sizeof_field(struct io_kiocb, cmd.data),
+	};
+
 #define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
 	BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
 	BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
@@ -3722,12 +3727,9 @@ static int __init io_uring_init(void)
 	 * range, and HARDENED_USERCOPY will complain if we haven't
 	 * correctly annotated this range.
 	 */
-	req_cachep = kmem_cache_create_usercopy("io_kiocb",
-				sizeof(struct io_kiocb), 0,
-				SLAB_HWCACHE_ALIGN | SLAB_PANIC |
-				SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU,
-				offsetof(struct io_kiocb, cmd.data),
-				sizeof_field(struct io_kiocb, cmd.data), NULL);
+	req_cachep = kmem_cache_create("io_kiocb", sizeof(struct io_kiocb), &kmem_args,
+				SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT |
+				SLAB_TYPESAFE_BY_RCU);
 	io_buf_cachep = KMEM_CACHE(io_buffer,
 					  SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);
 

-- 
2.45.2

Re: [PATCH v4 00/17] slab: add struct kmem_cache_args

[Vlastimil Babka]

On 9/5/24 9:56 AM, Christian Brauner wrote:
> Hey,
> 
> This is v4 which allows NULL to be passed in the struct kmem_cache_args
> argument of kmem_cache_create() and substitutes default parameters in
> this case.

Thanks, I've followed your earlier suggestion and put this series to a
branch that merges the vfs.file first:

https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git/log/?h=slab/for-6.12/kmem_cache_args

and I'm including it to slab/for-next

Meanwhile I think we should look at the kerneldocs for the new
kmem_cache_create() (hopefully kerneldoc can be persuaded to document it
without throwing errors) and the kmem_cache_args, because patches 16 and
14 just removed what we had before, including the details about
freeptr_offset in patch 14.

> As discussed last week the various kmem_cache_*() functions should be
> replaced by a unified function that is based around a struct, with only
> the basic parameters passed separately.
> 
> Vlastimil already said that he would like to keep core parameters out
> of the struct: name, object size, and flags. I personally don't care
> much and would not object to moving everything into the struct but
> that's a matter of taste and I yield that decision power to the
> maintainer.
> 
> In the first version I pointed out that the choice of name is somewhat
> forced as kmem_cache_create() is taken and the only way to reuse it
> would be to replace all users in one go. Or to do a global
> sed/kmem_cache_create()/kmem_cache_create2()/g. And then introduce
> kmem_cache_setup(). That doesn't strike me as a viable option.
> 
> If we really cared about the *_create() suffix then an alternative might
> be to do a sed/kmem_cache_setup()/kmem_cache_create()/g after every user
> in the kernel is ported. I honestly don't think that's worth it but I
> wanted to at least mention it to highlight the fact that this might lead
> to a naming compromise.
> 
> However, I came up with an alternative using _Generic() to create a
> compatibility layer that will call the correct variant of
> kmem_cache_create() depending on whether struct kmem_cache_args is
> passed or not. That compatibility layer can stay in place until we
> updated all calls to be based on struct kmem_cache_args.
> 
> From a cursory grep (and not excluding Documentation mentions) we will
> have to replace 44 kmem_cache_create_usercopy() calls and about 463
> kmem_cache_create() calls which makes for a bit above 500 calls to port
> to kmem_cache_setup(). That'll probably be good work for people getting
> into kernel development.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
> Changes in v4:
> - Allow NULL to be passed in the struct kmem_cache_args argument of
>   kmem_cache_create() and use default parameters in this case.
> - Link to v3: https://lore.kernel.org/r/20240904-work-kmem_cache_args-v3-0-05db2179a8c2@kernel.org
> 
> Changes in v3:
> - Reworded some commit messages.
> - Picked up various RvBs.
> - Added two patches to make two functions static inline.
> - Link to v2: https://lore.kernel.org/r/20240903-work-kmem_cache_args-v2-0-76f97e9a4560@kernel.org
> 
> Changes in v2:
> - Remove kmem_cache_setup() and add a compatibility layer built around
>   _Generic() so that we can keep the kmem_cache_create() name and type
>   switch on the third argument to either call __kmem_cache_create() or
>   __kmem_cache_create_args().
> - Link to v1: https://lore.kernel.org/r/20240902-work-kmem_cache_args-v1-0-27d05bc05128@kernel.org
> 
> ---
> Christian Brauner (17):
>       slab: s/__kmem_cache_create/do_kmem_cache_create/g
>       slab: add struct kmem_cache_args
>       slab: port kmem_cache_create() to struct kmem_cache_args
>       slab: port kmem_cache_create_rcu() to struct kmem_cache_args
>       slab: port kmem_cache_create_usercopy() to struct kmem_cache_args
>       slab: pass struct kmem_cache_args to create_cache()
>       slab: pull kmem_cache_open() into do_kmem_cache_create()
>       slab: pass struct kmem_cache_args to do_kmem_cache_create()
>       slab: remove rcu_freeptr_offset from struct kmem_cache
>       slab: port KMEM_CACHE() to struct kmem_cache_args
>       slab: port KMEM_CACHE_USERCOPY() to struct kmem_cache_args
>       slab: create kmem_cache_create() compatibility layer
>       file: port to struct kmem_cache_args
>       slab: remove kmem_cache_create_rcu()
>       slab: make kmem_cache_create_usercopy() static inline
>       slab: make __kmem_cache_create() static inline
>       io_uring: port to struct kmem_cache_args
> 
>  fs/file_table.c      |  11 ++-
>  include/linux/slab.h | 130 +++++++++++++++++++++++++++------
>  io_uring/io_uring.c  |  14 ++--
>  mm/slab.h            |   6 +-
>  mm/slab_common.c     | 197 +++++++++++----------------------------------------
>  mm/slub.c            | 162 +++++++++++++++++++++---------------------
>  6 files changed, 250 insertions(+), 270 deletions(-)
> ---
> base-commit: 6e016babce7c845ed015da25c7a097fa3482d95a
> change-id: 20240902-work-kmem_cache_args-e9760972c7d4
>