From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760887AbYGaAHL (ORCPT ); Wed, 30 Jul 2008 20:07:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754770AbYGaAGy (ORCPT ); Wed, 30 Jul 2008 20:06:54 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36064 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752912AbYGaAGx (ORCPT ); Wed, 30 Jul 2008 20:06:53 -0400 Date: Wed, 30 Jul 2008 16:58:07 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Marcelo Tosatti , Avi Kivity Subject: [patch 10/62] KVM: mmu_shrink: kvm_mmu_zap_page requires slots_lock to be held Message-ID: <20080730235807.GJ12896@suse.de> References: <20080730233050.332789722@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="kvm-mmu_shrink-kvm_mmu_zap_page-requires-slots_lock-to-be-held.patch" In-Reply-To: <20080730234915.GA12426@suse.de> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.26 -stable review patch. If anyone has any objections, please let us know. ------------------ From: Marcelo Tosatti Original-Commit-Hash: 64f6a0c041bd8fc100a0d655058bdbc31feda03c kvm_mmu_zap_page() needs slots lock held (rmap_remove->gfn_to_memslot, for example). Since kvm_lock spinlock is held in mmu_shrink(), do a non-blocking down_read_trylock(). Untested. Signed-off-by: Avi Kivity Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/mmu.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1968,6 +1968,8 @@ static int mmu_shrink(int nr_to_scan, gf list_for_each_entry(kvm, &vm_list, vm_list) { int npages; + if (!down_read_trylock(&kvm->slots_lock)) + continue; spin_lock(&kvm->mmu_lock); npages = kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages; @@ -1980,6 +1982,7 @@ static int mmu_shrink(int nr_to_scan, gf nr_to_scan--; spin_unlock(&kvm->mmu_lock); + up_read(&kvm->slots_lock); } if (kvm_freed) list_move_tail(&kvm_freed->vm_list, &vm_list); --