Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751829Ab3FZMTN (ORCPT ); Wed, 26 Jun 2013 08:19:13 -0400 Received: from mail-pb0-f42.google.com ([209.85.160.42]:33198 "EHLO mail-pb0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751542Ab3FZMTM (ORCPT ); Wed, 26 Jun 2013 08:19:12 -0400 Message-ID: <51CADC39.1070905@ozlabs.ru> Date: Wed, 26 Jun 2013 22:19:05 +1000 From: Alexey Kardashevskiy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 MIME-Version: 1.0 To: Benjamin Herrenschmidt CC: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org, David Gibson , Paul Mackerras , Anton Blanchard , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] powerpc/vfio: Add missing locks for take/release TCE table ownership References: <1372227662-28302-1-git-send-email-aik@ozlabs.ru> In-Reply-To: <1372227662-28302-1-git-send-email-aik@ozlabs.ru> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2717 Lines: 92 Ben, please ignore this. Need some more code there. On 06/26/2013 04:21 PM, Alexey Kardashevskiy wrote: > VFIO IOMMU driver for sPAPR TCE locks the whole DMA window by setting > ones to iommu_table.it_map. However this was not protected by the locks > which other clients of iommu_table use. > > The patch fixes this. > > Signed-off-by: Alexey Kardashevskiy > --- > > v1->v2: > * Fixed a potential warning from lockdep. > > --- > arch/powerpc/kernel/iommu.c | 25 +++++++++++++++++++++++-- > 1 file changed, 23 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c > index b20ff17..5c1fc89 100644 > --- a/arch/powerpc/kernel/iommu.c > +++ b/arch/powerpc/kernel/iommu.c > @@ -1076,25 +1076,42 @@ EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode); > int iommu_take_ownership(struct iommu_table *tbl) > { > unsigned long sz = (tbl->it_size + 7) >> 3; > + unsigned long i, flags; > + int ret = 0; > + > + spin_lock_irqsave(&tbl->large_pool.lock, flags); > + for (i = 0; i < tbl->nr_pools; i++) > + spin_lock(&tbl->pools[i].lock); > > if (tbl->it_offset == 0) > clear_bit(0, tbl->it_map); > > if (!bitmap_empty(tbl->it_map, tbl->it_size)) { > pr_err("iommu_tce: it_map is not empty"); > - return -EBUSY; > + ret = -EBUSY; > + goto unlock_exit; > } > > memset(tbl->it_map, 0xff, sz); > iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size); > > - return 0; > +unlock_exit: > + for (i = 0; i < tbl->nr_pools; i++) > + spin_unlock(&tbl->pools[i].lock); > + spin_unlock_irqrestore(&tbl->large_pool.lock, flags); > + > + return ret; > } > EXPORT_SYMBOL_GPL(iommu_take_ownership); > > void iommu_release_ownership(struct iommu_table *tbl) > { > unsigned long sz = (tbl->it_size + 7) >> 3; > + unsigned long i, flags; > + > + spin_lock_irqsave(&tbl->large_pool.lock, flags); > + for (i = 0; i < tbl->nr_pools; i++) > + spin_lock(&tbl->pools[i].lock); > > iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size); > memset(tbl->it_map, 0, sz); > @@ -1102,6 +1119,10 @@ void iommu_release_ownership(struct iommu_table *tbl) > /* Restore bit#0 set by iommu_init_table() */ > if (tbl->it_offset == 0) > set_bit(0, tbl->it_map); > + > + for (i = 0; i < tbl->nr_pools; i++) > + spin_unlock(&tbl->pools[i].lock); > + spin_unlock_irqrestore(&tbl->large_pool.lock, flags); > } > EXPORT_SYMBOL_GPL(iommu_release_ownership); > > -- Alexey -- 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/