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authorJason Gunthorpe <jgg@mellanox.com>2020-03-05 21:27:20 +0300
committerJason Gunthorpe <jgg@mellanox.com>2020-03-26 20:33:37 +0300
commit4055062749229101365e5f9e87cb1c5a93e292f8 (patch)
treeea0e9cfb1deaa87f6900242af536f46192ba2931 /mm/hmm.c
parent2288a9a68175cec9f91afb52948ba585b690774b (diff)
downloadlinux-4055062749229101365e5f9e87cb1c5a93e292f8.tar.xz
mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling
Currently if a special PTE is encountered hmm_range_fault() immediately returns EFAULT and sets the HMM_PFN_SPECIAL error output (which nothing uses). EFAULT should only be returned after testing with hmm_pte_need_fault(). Also pte_devmap() and pte_special() are exclusive, and there is no need to check IS_ENABLED, pte_special() is stubbed out to return false on unsupported architectures. Fixes: 992de9a8b751 ("mm/hmm: allow to mirror vma of a file on a DAX backed filesystem") Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> 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.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index 3a03fcff2668..9c82ea972d4b 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -339,16 +339,21 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
pte_unmap(ptep);
return -EBUSY;
}
- } else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) {
- if (!is_zero_pfn(pte_pfn(pte))) {
+ }
+
+ /*
+ * Since each architecture defines a struct page for the zero page, just
+ * fall through and treat it like a normal page.
+ */
+ if (pte_special(pte) && !is_zero_pfn(pte_pfn(pte))) {
+ hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault,
+ &write_fault);
+ if (fault || write_fault) {
pte_unmap(ptep);
- *pfn = range->values[HMM_PFN_SPECIAL];
return -EFAULT;
}
- /*
- * Since each architecture defines a struct page for the zero
- * page, just fall through and treat it like a normal page.
- */
+ *pfn = range->values[HMM_PFN_SPECIAL];
+ return 0;
}
*pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags;