From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: [PATCH] rbd: flush dcache after zeroing page data Date: Thu, 23 May 2013 11:54:04 -0700 Message-ID: <519E65CC.3060208@inktank.com> References: <519E0781.4000603@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f45.google.com ([209.85.160.45]:43239 "EHLO mail-pb0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758494Ab3EWSza (ORCPT ); Thu, 23 May 2013 14:55:30 -0400 Received: by mail-pb0-f45.google.com with SMTP id mc17so3257914pbc.32 for ; Thu, 23 May 2013 11:55:29 -0700 (PDT) In-Reply-To: <519E0781.4000603@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alex Elder Cc: ceph-devel@vger.kernel.org Reviewed-by: Josh Durgin On 05/23/2013 05:11 AM, Alex Elder wrote: > Neither zero_bio_chain() nor zero_pages() contains a call to flush > caches after zeroing a portion of a page. This can cause problems > on architectures that have caches that allow virtual address > aliasing. > > This resolves: > http://tracker.ceph.com/issues/4777 > > Signed-off-by: Alex Elder > --- > drivers/block/rbd.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c > index 6e377a0..f860dd6 100644 > --- a/drivers/block/rbd.c > +++ b/drivers/block/rbd.c > @@ -1124,6 +1124,7 @@ static void zero_bio_chain(struct bio *chain, int > start_ofs) > buf = bvec_kmap_irq(bv, &flags); > memset(buf + remainder, 0, > bv->bv_len - remainder); > + flush_dcache_page(bv->bv_page); > bvec_kunmap_irq(buf, &flags); > } > pos += bv->bv_len; > @@ -1156,6 +1157,7 @@ static void zero_pages(struct page **pages, u64 > offset, u64 end) > local_irq_save(flags); > kaddr = kmap_atomic(*page); > memset(kaddr + page_offset, 0, length); > + flush_dcache_page(*page); > kunmap_atomic(kaddr); > local_irq_restore(flags); >