From 15520a3f046998e3f57e695743e99b0875e2dae7 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Sun, 30 Oct 2022 17:41:51 -0400 Subject: mm: use pte markers for swap errors PTE markers are ideal mechanism for things like SWP_SWAPIN_ERROR. Using a whole swap entry type for this purpose can be an overkill, especially if we already have PTE markers. Define a new bit for swapin error and replace it with pte markers. Then we can safely drop SWP_SWAPIN_ERROR and give one device slot back to swap. We used to have SWP_SWAPIN_ERROR taking the page pfn as part of the swap entry, but it's never used. Neither do I see how it can be useful because normally the swapin failure should not be caused by a bad page but bad swap device. Drop it alongside. Link: https://lkml.kernel.org/r/20221030214151.402274-3-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Huang Ying Reviewed-by: Miaohe Lin Acked-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Naoya Horiguchi Signed-off-by: Andrew Morton --- mm/memory.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index b79d27533722..142c4229549b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3668,6 +3668,10 @@ static vm_fault_t handle_pte_marker(struct vm_fault *vmf) if (WARN_ON_ONCE(!marker)) return VM_FAULT_SIGBUS; + /* Higher priority than uffd-wp when data corrupted */ + if (marker & PTE_MARKER_SWAPIN_ERROR) + return VM_FAULT_SIGBUS; + if (pte_marker_entry_uffd_wp(entry)) return pte_marker_handle_uffd_wp(vmf); @@ -3727,8 +3731,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) put_page(vmf->page); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON; - } else if (is_swapin_error_entry(entry)) { - ret = VM_FAULT_SIGBUS; } else if (is_pte_marker_entry(entry)) { ret = handle_pte_marker(vmf); } else { -- cgit v1.2.3