From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753747AbdEQJD6 (ORCPT ); Wed, 17 May 2017 05:03:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:47716 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751789AbdEQJDy (ORCPT ); Wed, 17 May 2017 05:03:54 -0400 Date: Wed, 17 May 2017 11:03:50 +0200 From: Michal Hocko To: Chris Wilson Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Daniel Vetter , Jani Nikula , Sean Paul , David Airlie Subject: Re: [PATCH 1/2] drm: replace drm_[cm]alloc* by kvmalloc alternatives Message-ID: <20170517090350.GG18247@dhcp22.suse.cz> References: <20170517065509.18659-1-mhocko@kernel.org> <20170517073809.GJ26693@nuc-i3427.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170517073809.GJ26693@nuc-i3427.alporthouse.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 17-05-17 08:38:09, Chris Wilson wrote: > On Wed, May 17, 2017 at 08:55:08AM +0200, Michal Hocko wrote: > > From: Michal Hocko > > > > drm_[cm]alloc* has grown their own kvmalloc with vmalloc fallback > > implementations. MM has grown kvmalloc* helpers in the meantime. Let's > > use those because it a) reduces the code and b) MM has a better idea > > how to implement fallbacks (e.g. do not vmalloc before kmalloc is tried > > with __GFP_NORETRY). > > > > drm_calloc_large needs to get __GFP_ZERO explicitly but it is the same > > thing as kvmalloc_array in principle. > > > > Signed-off-by: Michal Hocko > > Just a little surprised that calloc_large users still exist. > > Reviewed-by: Chris Wilson Thanks! > One more feature request from mm, can we have the > if (size != 0 && n > SIZE_MAX / size) > check exported by itself. What do you exactly mean by exporting? Something like the following? I haven't compile tested it outside of mm with different config options. Sticking alloc_array_check into mm_types.h is kind of gross but I do not have a great idea where to put it. A new header doesn't seem nice. --- diff --git a/include/linux/mm.h b/include/linux/mm.h index 7cb17c6b97de..f908b14ffc4c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -534,7 +534,7 @@ static inline void *kvzalloc(size_t size, gfp_t flags) static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags) { - if (size != 0 && n > SIZE_MAX / size) + if (!alloc_array_check(n, size)) return NULL; return kvmalloc(n * size, flags); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 45cdb27791a3..d7154b43a0d1 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -601,4 +601,10 @@ typedef struct { unsigned long val; } swp_entry_t; +static inline bool alloc_array_check(size_t n, size_t size) +{ + if (size != 0 && n > SIZE_MAX / size) + return false; + return true; +} #endif /* _LINUX_MM_TYPES_H */ diff --git a/include/linux/slab.h b/include/linux/slab.h index 3c37a8c51921..e936ca7c55a1 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -602,7 +602,7 @@ int memcg_update_all_caches(int num_memcgs); */ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) { - if (size != 0 && n > SIZE_MAX / size) + if (!alloc_array_check(n, size)) return NULL; if (__builtin_constant_p(n) && __builtin_constant_p(size)) return kmalloc(n * size, flags); -- Michal Hocko SUSE Labs