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Message-ID: <20191211104236.GM1551@quack2.suse.cz> Date: Wed, 11 Dec 2019 11:42:36 +0100 From: Jan Kara <jack@...e.cz> To: John Hubbard <jhubbard@...dia.com> Cc: Andrew Morton <akpm@...ux-foundation.org>, Al Viro <viro@...iv.linux.org.uk>, Alex Williamson <alex.williamson@...hat.com>, Benjamin Herrenschmidt <benh@...nel.crashing.org>, Björn Töpel <bjorn.topel@...el.com>, Christoph Hellwig <hch@...radead.org>, Dan Williams <dan.j.williams@...el.com>, Daniel Vetter <daniel@...ll.ch>, Dave Chinner <david@...morbit.com>, David Airlie <airlied@...ux.ie>, "David S . Miller" <davem@...emloft.net>, Ira Weiny <ira.weiny@...el.com>, Jan Kara <jack@...e.cz>, Jason Gunthorpe <jgg@...pe.ca>, Jens Axboe <axboe@...nel.dk>, Jonathan Corbet <corbet@....net>, Jérôme Glisse <jglisse@...hat.com>, Magnus Karlsson <magnus.karlsson@...el.com>, Mauro Carvalho Chehab <mchehab@...nel.org>, Michael Ellerman <mpe@...erman.id.au>, Michal Hocko <mhocko@...e.com>, Mike Kravetz <mike.kravetz@...cle.com>, Paul Mackerras <paulus@...ba.org>, Shuah Khan <shuah@...nel.org>, Vlastimil Babka <vbabka@...e.cz>, bpf@...r.kernel.org, dri-devel@...ts.freedesktop.org, kvm@...r.kernel.org, linux-block@...r.kernel.org, linux-doc@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-kselftest@...r.kernel.org, linux-media@...r.kernel.org, linux-rdma@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, netdev@...r.kernel.org, linux-mm@...ck.org, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v9 20/25] powerpc: book3s64: convert to pin_user_pages() and put_user_page() On Tue 10-12-19 18:53:13, John Hubbard wrote: > 1. Convert from get_user_pages() to pin_user_pages(). > > 2. As required by pin_user_pages(), release these pages via > put_user_page(). > > Cc: Jan Kara <jack@...e.cz> > Signed-off-by: John Hubbard <jhubbard@...dia.com> The patch looks good to me. You can add: Reviewed-by: Jan Kara <jack@...e.cz> I'd just note that mm_iommu_do_alloc() has a pre-existing bug that the last jump to 'free_exit' (at line 157) happens already after converting page pointers to physical addresses so put_page() calls there will just crash. But that's completely unrelated to your change. I'll send a fix separately. Honza > --- > arch/powerpc/mm/book3s64/iommu_api.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c > index 56cc84520577..a86547822034 100644 > --- a/arch/powerpc/mm/book3s64/iommu_api.c > +++ b/arch/powerpc/mm/book3s64/iommu_api.c > @@ -103,7 +103,7 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, > for (entry = 0; entry < entries; entry += chunk) { > unsigned long n = min(entries - entry, chunk); > > - ret = get_user_pages(ua + (entry << PAGE_SHIFT), n, > + ret = pin_user_pages(ua + (entry << PAGE_SHIFT), n, > FOLL_WRITE | FOLL_LONGTERM, > mem->hpages + entry, NULL); > if (ret == n) { > @@ -167,9 +167,8 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, > return 0; > > free_exit: > - /* free the reference taken */ > - for (i = 0; i < pinned; i++) > - put_page(mem->hpages[i]); > + /* free the references taken */ > + put_user_pages(mem->hpages, pinned); > > vfree(mem->hpas); > kfree(mem); > @@ -215,7 +214,8 @@ static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem) > if (mem->hpas[i] & MM_IOMMU_TABLE_GROUP_PAGE_DIRTY) > SetPageDirty(page); > > - put_page(page); > + put_user_page(page); > + > mem->hpas[i] = 0; > } > } > -- > 2.24.0 > -- Jan Kara <jack@...e.com> SUSE Labs, CR
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