mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range

Once the MADV_FREE operation has succeeded, callers can expect they might
get zero-fill pages if accessing the memory again.  Therefore it should be
safe to delete the hwpoison entry and swapin error entry.  There is no
reason to kill the process if it has called MADV_FREE on the range.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Miaohe Lin <[email protected]>
Suggested-by: Alistair Popple <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Cc: David Howells <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: NeilBrown <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Ralph Campbell <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 8 insertions, 5 deletions

diff --git a/mm/madvise.c b/mm/madvise.c
index 4d6592488b51..5f4537511532 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -624,11 +624,14 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
 			swp_entry_t entry;
 
 			entry = pte_to_swp_entry(ptent);
-			if (non_swap_entry(entry))
-				continue;
-			nr_swap--;
-			free_swap_and_cache(entry);
-			pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
+			if (!non_swap_entry(entry)) {
+				nr_swap--;
+				free_swap_and_cache(entry);
+				pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
+			} else if (is_hwpoison_entry(entry) ||
+				   is_swapin_error_entry(entry)) {
+				pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
+			}
 			continue;
 		}