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authorDan Williams <dan.j.williams@intel.com>2018-02-23 14:06:16 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-28 10:18:34 +0100
commit78b1cb3fe38a509dc0fdbdb52c742d4630db7502 (patch)
tree601eaa282693104c580fcf45caa7080c6ce83734
parent8f7cf88d59f0026af8d4c9fe0a14a445ba499d93 (diff)
mm: fail get_vaddr_frames() for filesystem-dax mappings
commit b7f0554a56f21fb3e636a627450a9add030889be upstream. Until there is a solution to the dma-to-dax vs truncate problem it is not safe to allow V4L2, Exynos, and other frame vector users to create long standing / irrevocable memory registrations against filesytem-dax vmas. [dan.j.williams@intel.com: add comment for vma_is_fsdax() check in get_vaddr_frames(), per Jan] Link: http://lkml.kernel.org/r/151197874035.26211.4061781453123083667.stgit@dwillia2-desk3.amr.corp.intel.com Link: http://lkml.kernel.org/r/151068939985.7446.15684639617389154187.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Inki Dae <inki.dae@samsung.com> Cc: Seung-Woo Kim <sw0312.kim@samsung.com> Cc: Joonyoung Shim <jy0922.shim@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Doug Ledford <dledford@redhat.com> Cc: Hal Rosenstock <hal.rosenstock@gmail.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Sean Hefty <sean.hefty@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/frame_vector.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index db77dcb38afd..375a103d7a56 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -52,6 +52,18 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
ret = -EFAULT;
goto out;
}
+
+ /*
+ * While get_vaddr_frames() could be used for transient (kernel
+ * controlled lifetime) pinning of memory pages all current
+ * users establish long term (userspace controlled lifetime)
+ * page pinning. Treat get_vaddr_frames() like
+ * get_user_pages_longterm() and disallow it for filesystem-dax
+ * mappings.
+ */
+ if (vma_is_fsdax(vma))
+ return -EOPNOTSUPP;
+
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
vec->got_ref = true;
vec->is_pfns = false;