From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 371A31A01F2 for ; Wed, 13 Aug 2014 21:56:32 +1000 (EST) Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 13 Aug 2014 21:56:30 +1000 Received: from d23relay06.au.ibm.com (d23relay06.au.ibm.com [9.185.63.219]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id AB6F62CE8051 for ; Wed, 13 Aug 2014 21:56:26 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay06.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s7DBv9Od12976338 for ; Wed, 13 Aug 2014 21:57:11 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s7DBuOlS021414 for ; Wed, 13 Aug 2014 21:56:24 +1000 From: "Aneesh Kumar K.V" To: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] PC, KVM, CMA: Fix regression caused by wrong get_order() use In-Reply-To: <1407903739-7064-1-git-send-email-aik@ozlabs.ru> References: <1407903739-7064-1-git-send-email-aik@ozlabs.ru> Date: Wed, 13 Aug 2014 17:26:13 +0530 Message-ID: <87mwb861sy.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Cc: kvm@vger.kernel.org, Alexey Kardashevskiy , Alexander Graf , kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org, Gleb Natapov , Paul Mackerras , stable@vger.kernel.org, Paolo Bonzini , Joonsoo Kim List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Alexey Kardashevskiy writes: > fc95ca7284bc54953165cba76c3228bd2cdb9591 claims that there is no > functional change but this is not true as it calls get_order() (which > takes bytes) where it should have called ilog2() and the kernel stops > on VM_BUG_ON(). > > This replaces get_order() with ilog2(). Should we round it up ? ie, ilog2(kvm_rma_pages - 1) + 1 ? > > Suggested-by: Paul Mackerras > Cc: Alexander Graf > Cc: Aneesh Kumar K.V > Cc: Joonsoo Kim > Cc: Benjamin Herrenschmidt > Cc: Why stable ? We merged it this merge window. > Signed-off-by: Alexey Kardashevskiy > --- > arch/powerpc/kvm/book3s_hv_builtin.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c > index 329d7fd..bfe9f01 100644 > --- a/arch/powerpc/kvm/book3s_hv_builtin.c > +++ b/arch/powerpc/kvm/book3s_hv_builtin.c > @@ -101,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma() > ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL); > if (!ri) > return NULL; > - page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages)); > + page = cma_alloc(kvm_cma, kvm_rma_pages, ilog2(kvm_rma_pages)); > if (!page) > goto err_out; > atomic_set(&ri->use_count, 1); > @@ -135,12 +135,12 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages) > { > unsigned long align_pages = HPT_ALIGN_PAGES; > > - VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); > + VM_BUG_ON(ilog2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); > > /* Old CPUs require HPT aligned on a multiple of its size */ > if (!cpu_has_feature(CPU_FTR_ARCH_206)) > align_pages = nr_pages; > - return cma_alloc(kvm_cma, nr_pages, get_order(align_pages)); > + return cma_alloc(kvm_cma, nr_pages, ilog2(align_pages)); > } > EXPORT_SYMBOL_GPL(kvm_alloc_hpt); > > -- > 2.0.0