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b=ZQGxyQ10x7HsHlCcZvcZg/0OVRmZGpJerHpk9vw95gyIbXvnvMTY6uOmLciBFbEad cMhiDsJ/PrjxYYrhYe6juPxPaDRPjwRuzPxvF8zIOjWobm+iHaCp5YYfd+L/zla0ai a8QNzlFj2JDCcPmXFpH7rkLvAbsrtX5ZnRToM7JqOKLNdvz6mIxM1FxuWtYuo2KHkv uwuPHg+YUhoqJegHnMUk3deIqtZ3CXVic/QU6cqL97WlK0vDO+Q3ORDR2Iz8OMtGLt Y4cFB4YAuhr9o6D1M4dFtk8TB3pBdIehVwwCJu2w4Mz5Ihl69l3p2oouqFoKf/SyAj +PLYgIw/8rjYg== Date: Wed, 4 Sep 2024 17:48:31 +0200 From: Christian Brauner To: Mike Rapoport Cc: Vlastimil Babka , Jens Axboe , Jann Horn , Linus Torvalds , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 02/15] slab: add struct kmem_cache_args Message-ID: <20240904-bauaufsicht-gewohnheit-a70bd9266986@brauner> References: <20240903-work-kmem_cache_args-v2-0-76f97e9a4560@kernel.org> <20240903-work-kmem_cache_args-v2-2-76f97e9a4560@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Stat-Signature: 4mcatms9ypfwzn7pnnsuy119iah5ahxi X-Rspamd-Queue-Id: D35771C0002 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1725464917-222812 X-HE-Meta: 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 vKIbdxH1 rzfm68bcts9mc90b8+yLrSRHK5jXoUi5p8no96OQ5iRW8GK2KqPnF2SxxS/xtk32DvWEzRYbEkrB+VFNioWIBFis5+bt1Vy0y4dUTusTtgM7x762/ouSI4sYdtcgxU/k2WtreacoTKpDG6vtTh1FgizcsbnJY6XdarmSUZ8wuWmGG43Pi+zkPPhgChpTIvn+F8dvEimOT45mmC/XY2N4/60xlKGglddOlkwoYBnhi+BJInwYTQvdKlWKjL7tds+oGYAV/jVFkbTMZVHbtqN3zXFgYmdsVCzR+AqlCZltBSA+5C5EphtZ07NNQqdNT0ybiqsr0Acdnnuzf0dC6pcqj5OBz8bf9mrpXSEUfArihJGZGyHGwAHGdy5Z0hQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Sep 04, 2024 at 06:16:16PM GMT, Mike Rapoport wrote: > On Tue, Sep 03, 2024 at 04:20:43PM +0200, Christian Brauner wrote: > > Signed-off-by: Christian Brauner > > --- > > 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); > > Sorry I missed it in the previous review, but nothing guaranties that > nobody will call kmem_cache_create_args with args != NULL. > > I think there should be a check for args != NULL and a substitution of args > with defaults if it actually was NULL. I think that callers that pass NULL should all be switched to KMEM_CACHE() and passing NULL should simply not be supported. And the few callers that need some very special alignment need to pass struct kmem_cache_args anyway. So there should never be a need to pass NULL.