From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754688Ab1LAOTo (ORCPT ); Thu, 1 Dec 2011 09:19:44 -0500 Received: from cantor2.suse.de ([195.135.220.15]:39426 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754562Ab1LAOTn (ORCPT ); Thu, 1 Dec 2011 09:19:43 -0500 Date: Thu, 1 Dec 2011 15:19:41 +0100 From: Michal Hocko To: linux-kernel@vger.kernel.org Cc: David Howells , Andrea Arcangeli Subject: Re: [PATCH 1/3] frv: remove irqsave pgd_lock locking Message-ID: <20111201141941.GA4490@tiehlicka.suse.cz> References: <1320853639-18048-1-git-send-email-mhocko@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1320853639-18048-1-git-send-email-mhocko@suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping On Wed 09-11-11 16:47:17, Michal Hocko wrote: > a79e53d8: x86/mm: Fix pgd_lock deadlock dropped irqsave locking to fix a > deadlock. pgd_lock is not used from an irq context so we can drop > irqsave locking here as well. > The original patch was x86 only but the same applies here because both > pgd_ctor (aka mm_alloc_pgd) and pgd_dtor (aka mm_free_pgd) are not used > from an interrupt contexts. > > Signed-off-by: Michal Hocko > Cc: David Howells > Cc: Andrea Arcangeli > --- > arch/frv/mm/pgalloc.c | 12 ++++-------- > 1 files changed, 4 insertions(+), 8 deletions(-) > > diff --git a/arch/frv/mm/pgalloc.c b/arch/frv/mm/pgalloc.c > index 4fb63a3..9df65c6 100644 > --- a/arch/frv/mm/pgalloc.c > +++ b/arch/frv/mm/pgalloc.c > @@ -104,10 +104,8 @@ static inline void pgd_list_del(pgd_t *pgd) > > void pgd_ctor(void *pgd) > { > - unsigned long flags; > - > if (PTRS_PER_PMD == 1) > - spin_lock_irqsave(&pgd_lock, flags); > + spin_lock(&pgd_lock); > > memcpy((pgd_t *) pgd + USER_PGDS_IN_LAST_PML4, > swapper_pg_dir + USER_PGDS_IN_LAST_PML4, > @@ -117,18 +115,16 @@ void pgd_ctor(void *pgd) > return; > > pgd_list_add(pgd); > - spin_unlock_irqrestore(&pgd_lock, flags); > + spin_unlock(&pgd_lock); > memset(pgd, 0, USER_PGDS_IN_LAST_PML4 * sizeof(pgd_t)); > } > > /* never called when PTRS_PER_PMD > 1 */ > void pgd_dtor(void *pgd) > { > - unsigned long flags; /* can be called from interrupt context */ > - > - spin_lock_irqsave(&pgd_lock, flags); > + spin_lock(&pgd_lock); > pgd_list_del(pgd); > - spin_unlock_irqrestore(&pgd_lock, flags); > + spin_unlock(&pgd_lock); > } > > pgd_t *pgd_alloc(struct mm_struct *mm) > -- > 1.7.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic