From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH 2/3] mm: use vmalloc_array and vcalloc for array allocations Date: Tue, 8 Mar 2022 14:49:01 +0100 Message-ID: References: <20220308105918.615575-1-pbonzini@redhat.com> <20220308105918.615575-3-pbonzini@redhat.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1646747341; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=SyTgM5F6+9CT4oBrYUK4bC/XMWpEt2BZNDE3I1Sk7Ys=; b=SOLJf8KzF3lpV2Z1nK2RtJ/mCHih8E/LOT3+NtV9WjuFZrbvkvNGfz9md9KsmuMAmYb4xl mrgfppZj4eTymdy2LnRjU7ToP7z5QKvHD+Fb5G9Y3hGjHgDOXnP7/F9d/3dhoWrdQoV6gE PQ9kK/Trd67H0yxar7509l2hpkGD6SA= Content-Disposition: inline In-Reply-To: <20220308105918.615575-3-pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Paolo Bonzini Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michael Ellerman , Andrew Morton , Dennis Zhou , Tejun Heo , Christoph Lameter , Johannes Weiner , Vladimir Davydov , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Tue 08-03-22 05:59:17, Paolo Bonzini wrote: > Instead of using array_size or just a multiply, use a function that > takes care of both the multiplication and the overflow checks. > > Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org > Signed-off-by: Paolo Bonzini Acked-by: Michal Hocko The resulting code is easier to read indeed. > --- > mm/percpu-stats.c | 2 +- > mm/swap_cgroup.c | 4 +--- > 2 files changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c > index c6bd092ff7a3..e71651cda2de 100644 > --- a/mm/percpu-stats.c > +++ b/mm/percpu-stats.c > @@ -144,7 +144,7 @@ static int percpu_stats_show(struct seq_file *m, void *v) > spin_unlock_irq(&pcpu_lock); > > /* there can be at most this many free and allocated fragments */ > - buffer = vmalloc(array_size(sizeof(int), (2 * max_nr_alloc + 1))); > + buffer = vmalloc_array(2 * max_nr_alloc + 1, sizeof(int)); > if (!buffer) > return -ENOMEM; > > diff --git a/mm/swap_cgroup.c b/mm/swap_cgroup.c > index 7f34343c075a..5a9442979a18 100644 > --- a/mm/swap_cgroup.c > +++ b/mm/swap_cgroup.c > @@ -167,14 +167,12 @@ unsigned short lookup_swap_cgroup_id(swp_entry_t ent) > int swap_cgroup_swapon(int type, unsigned long max_pages) > { > void *array; > - unsigned long array_size; > unsigned long length; > struct swap_cgroup_ctrl *ctrl; > > length = DIV_ROUND_UP(max_pages, SC_PER_PAGE); > - array_size = length * sizeof(void *); > > - array = vzalloc(array_size); > + array = vcalloc(length, sizeof(void *)); > if (!array) > goto nomem; > > -- > 2.31.1 > > -- Michal Hocko SUSE Labs