From: John Hubbard <jhubbard@nvidia.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Michal Hocko" <mhocko@suse.com>, "Jan Kara" <jack@suse.cz>,
kvm@vger.kernel.org, linux-doc@vger.kernel.org,
"David Airlie" <airlied@linux.ie>,
"Dave Chinner" <david@fromorbit.com>,
dri-devel@lists.freedesktop.org,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, "Paul Mackerras" <paulus@samba.org>,
linux-kselftest@vger.kernel.org,
"Ira Weiny" <ira.weiny@intel.com>,
"Jonathan Corbet" <corbet@lwn.net>,
linux-rdma@vger.kernel.org,
"Christoph Hellwig" <hch@infradead.org>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Björn Töpel" <bjorn.topel@intel.com>,
linux-media@vger.kernel.org, "Shuah Khan" <shuah@kernel.org>,
"John Hubbard" <jhubbard@nvidia.com>,
linux-block@vger.kernel.org, "Jérôme Glisse" <jglisse@redhat.com>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Dan Williams" <dan.j.williams@intel.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"Jens Axboe" <axboe@kernel.dk>,
netdev@vger.kernel.org,
"Alex Williamson" <alex.williamson@redhat.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org,
"David S . Miller" <davem@davemloft.net>,
"Mike Kravetz" <mike.kravetz@oracle.com>
Subject: [PATCH 14/19] vfio, mm: pin_longterm_pages (FOLL_PIN) and put_user_page() conversion
Date: Wed, 30 Oct 2019 15:49:25 -0700 [thread overview]
Message-ID: <20191030224930.3990755-15-jhubbard@nvidia.com> (raw)
In-Reply-To: <20191030224930.3990755-1-jhubbard@nvidia.com>
This also fixes one or two likely bugs.
1. Change vfio from get_user_pages(FOLL_LONGTERM), to
pin_longterm_pages(), which sets both FOLL_LONGTERM and FOLL_PIN.
Note that this is a change in behavior, because the
get_user_pages_remote() call was not setting FOLL_LONGTERM, but the
new pin_user_pages_remote() call that replaces it, *is* setting
FOLL_LONGTERM. It is important to set FOLL_LONGTERM, because the
DMA case requires it. Please see the FOLL_PIN documentation in
include/linux/mm.h, and Documentation/pin_user_pages.rst for details.
2. Because all FOLL_PIN-acquired pages must be released via
put_user_page(), also convert the put_page() call over to
put_user_pages().
Note that this effectively changes the code's behavior in
vfio_iommu_type1.c: put_pfn(): it now ultimately calls
set_page_dirty_lock(), instead of set_page_dirty(). This is
probably more accurate.
As Christoph Hellwig put it, "set_page_dirty() is only safe if we are
dealing with a file backed page where we have reference on the inode it
hangs off." [1]
[1] https://lore.kernel.org/r/20190723153640.GB720@lst.de
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
drivers/vfio/vfio_iommu_type1.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index d864277ea16f..795e13f3ef08 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -327,9 +327,8 @@ static int put_pfn(unsigned long pfn, int prot)
{
if (!is_invalid_reserved_pfn(pfn)) {
struct page *page = pfn_to_page(pfn);
- if (prot & IOMMU_WRITE)
- SetPageDirty(page);
- put_page(page);
+
+ put_user_pages_dirty_lock(&page, 1, prot & IOMMU_WRITE);
return 1;
}
return 0;
@@ -349,11 +348,11 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
down_read(&mm->mmap_sem);
if (mm == current->mm) {
- ret = get_user_pages(vaddr, 1, flags | FOLL_LONGTERM, page,
- vmas);
+ ret = pin_longterm_pages(vaddr, 1, flags, page, vmas);
} else {
- ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page,
- vmas, NULL);
+ ret = pin_longterm_pages_remote(NULL, mm, vaddr, 1,
+ flags, page, vmas,
+ NULL);
/*
* The lifetime of a vaddr_get_pfn() page pin is
* userspace-controlled. In the fs-dax case this could
@@ -363,7 +362,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
*/
if (ret > 0 && vma_is_fsdax(vmas[0])) {
ret = -EOPNOTSUPP;
- put_page(page[0]);
+ put_user_page(page[0]);
}
}
up_read(&mm->mmap_sem);
--
2.23.0
next prev parent reply other threads:[~2019-10-30 23:22 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 22:49 [PATCH 00/19] mm/gup: track dma-pinned pages: FOLL_PIN, FOLL_LONGTERM John Hubbard
2019-10-30 22:49 ` [PATCH 01/19] mm/gup: pass flags arg to __gup_device_* functions John Hubbard
2019-10-31 18:18 ` Ira Weiny
2019-10-30 22:49 ` [PATCH 02/19] mm/gup: factor out duplicate code from four routines John Hubbard
2019-10-31 18:35 ` Ira Weiny
2019-10-31 18:43 ` John Hubbard
2019-10-31 21:09 ` Ira Weiny
2019-10-31 22:01 ` John Hubbard
2019-10-30 22:49 ` [PATCH 03/19] goldish_pipe: rename local pin_user_pages() routine John Hubbard
2019-10-31 18:36 ` Ira Weiny
2019-10-30 22:49 ` [PATCH 04/19] media/v4l2-core: set pages dirty upon releasing DMA buffers John Hubbard
2019-10-30 22:49 ` [PATCH 05/19] mm/gup: introduce pin_user_pages*() and FOLL_PIN John Hubbard
2019-10-31 23:15 ` Ira Weiny
2019-10-31 23:43 ` John Hubbard
2019-10-30 22:49 ` [PATCH 06/19] goldish_pipe: convert to pin_user_pages() and put_user_page() John Hubbard
2019-10-30 22:49 ` [PATCH 07/19] infiniband: set FOLL_PIN, FOLL_LONGTERM via pin_longterm_pages*() John Hubbard
2019-10-31 23:25 ` Ira Weiny
2019-10-31 23:49 ` John Hubbard
2019-10-30 22:49 ` [PATCH 08/19] mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote() John Hubbard
2019-10-31 23:35 ` Ira Weiny
2019-10-31 23:46 ` John Hubbard
2019-10-30 22:49 ` [PATCH 09/19] drm/via: set FOLL_PIN via pin_user_pages_fast() John Hubbard
2019-10-31 23:36 ` Ira Weiny
2019-11-04 18:10 ` Daniel Vetter
2019-11-04 19:20 ` John Hubbard
2019-11-05 9:49 ` Daniel Vetter
2019-11-05 18:16 ` John Hubbard
2019-10-30 22:49 ` [PATCH 10/19] fs/io_uring: set FOLL_PIN via pin_user_pages() John Hubbard
2019-10-31 23:37 ` Ira Weiny
2019-11-01 14:49 ` Jens Axboe
2019-10-30 22:49 ` [PATCH 11/19] net/xdp: " John Hubbard
2019-10-31 23:37 ` Ira Weiny
2019-11-02 11:01 ` Björn Töpel
2019-10-30 22:49 ` [PATCH 12/19] mm/gup: track FOLL_PIN pages John Hubbard
2019-10-30 22:49 ` [PATCH 13/19] media/v4l2-core: pin_longterm_pages (FOLL_PIN) and put_user_page() conversion John Hubbard
2019-10-31 23:38 ` Ira Weiny
2019-10-30 22:49 ` John Hubbard [this message]
2019-10-30 23:05 ` [PATCH 14/19] vfio, mm: " John Hubbard
2019-10-30 22:49 ` [PATCH 15/19] powerpc: book3s64: convert to pin_longterm_pages() and put_user_page() John Hubbard
2019-10-30 22:49 ` [PATCH 16/19] mm/gup_benchmark: support pin_user_pages() and related calls John Hubbard
2019-10-30 22:49 ` [PATCH 17/19] selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage John Hubbard
2019-10-30 22:49 ` [PATCH 18/19] mm/gup: remove support for gup(FOLL_LONGTERM) John Hubbard
2019-10-30 22:49 ` [PATCH 19/19] Documentation/vm: add pin_user_pages.rst John Hubbard
2019-10-31 23:49 ` Ira Weiny
2019-10-31 23:53 ` John Hubbard
2019-11-01 0:48 ` John Hubbard
2019-11-03 19:53 ` John Hubbard
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