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authorJason Gunthorpe <jgg@mellanox.com>2020-03-27 17:00:21 -0300
committerJason Gunthorpe <jgg@mellanox.com>2020-03-30 16:58:36 -0300
commitbd5d3587b218d33d70a835582dfe1d8f8498e702 (patch)
treedb5411fb8e0b0d82ef248753372d8d42d201fdbc /mm/hmm.c
parent53bfe17ff88faaadf024956e7cb2b295fae7744b (diff)
downloadlinux-bd5d3587b218d33d70a835582dfe1d8f8498e702.tar.bz2
mm/hmm: return error for non-vma snapshots
The pagewalker does not call most ops with NULL vma, those are all routed to hmm_vma_walk_hole() via ops->pte_hole instead. Thus hmm_vma_fault() is only called with a NULL vma from hmm_vma_walk_hole(), so hoist the NULL vma check to there. Now it is clear that snapshotting with no vma is a HMM_PFN_ERROR as without a vma we have no path to call hmm_vma_fault(). Link: https://lore.kernel.org/r/20200327200021.29372-10-jgg@ziepe.ca Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'mm/hmm.c')
-rw-r--r--mm/hmm.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index 9b6a8a26a1fa..280585833adf 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -83,9 +83,6 @@ static int hmm_vma_fault(unsigned long addr, unsigned long end,
WARN_ON_ONCE(!required_fault);
hmm_vma_walk->last = addr;
- if (!vma)
- return -EFAULT;
-
if (required_fault & HMM_NEED_WRITE_FAULT) {
if (!(vma->vm_flags & VM_WRITE))
return -EPERM;
@@ -170,6 +167,11 @@ static int hmm_vma_walk_hole(unsigned long addr, unsigned long end,
npages = (end - addr) >> PAGE_SHIFT;
pfns = &range->pfns[i];
required_fault = hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0);
+ if (!walk->vma) {
+ if (required_fault)
+ return -EFAULT;
+ return hmm_pfns_fill(addr, end, range, HMM_PFN_ERROR);
+ }
if (required_fault)
return hmm_vma_fault(addr, end, required_fault, walk);
hmm_vma_walk->last = addr;