diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 0795028f017c2..35e9a468d13e6 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -245,7 +245,7 @@ static inline struct folio *hugetlb_swap_entry_to_folio(swp_entry_t entry)
{
VM_BUG_ON(!is_migration_entry(entry) && !is_hwpoison_entry(entry));
- return page_folio(pfn_to_page(swp_offset(entry)));
+ return page_folio(pfn_to_page(swp_offset_pfn(entry)));
}
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 482f91577f8c0..db2f3a2946a07 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1418,9 +1418,19 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
if (pte_swp_uffd_wp(pte))
flags |= PM_UFFD_WP;
entry = pte_to_swp_entry(pte);
- if (pm->show_pfn)
+ if (pm->show_pfn) {
+ pgoff_t offset;
+ /*
+ * For PFN swap offsets, keeping the offset field
+ * to be PFN only to be compatible with old smaps.
+ */
+ if (is_pfn_swap_entry(entry))
+ offset = swp_offset_pfn(entry);
+ else
+ offset = swp_offset(entry);
frame = swp_type(entry) |
- (swp_offset(entry) << MAX_SWAPFILES_SHIFT);
+ (offset << MAX_SWAPFILES_SHIFT);
+ }
flags |= PM_SWAP;
migration = is_migration_entry(entry);
if (is_pfn_swap_entry(entry))
@@ -1477,7 +1487,11 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
unsigned long offset;
if (pm->show_pfn) {
- offset = swp_offset(entry) +
+ if (is_pfn_swap_entry(entry))
+ offset = swp_offset_pfn(entry);
+ else
+ offset = swp_offset(entry);
+ offset = offset +
((addr & ~PMD_MASK) >> PAGE_SHIFT);
frame = swp_type(entry) |
(offset << MAX_SWAPFILES_SHIFT);
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 7d1b740465203..578212fbf2be9 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -23,6 +23,20 @@
#define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
#define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
+/*
+ * Definitions only for PFN swap entries (see is_pfn_swap_entry()). To
+ * store PFN, we only need SWP_PFN_BITS bits. Each of the pfn swap entries
+ * can use the extra bits to store other information besides PFN.
+ */
+#ifdef MAX_PHYSMEM_BITS
+#define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
+#else /* MAX_PHYSMEM_BITS */
+#define SWP_PFN_BITS (BITS_PER_LONG - PAGE_SHIFT)
+#endif /* MAX_PHYSMEM_BITS */
+#define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1)
+
+static inline bool is_pfn_swap_entry(swp_entry_t entry);
+
/* Clear all flags but only keep swp_entry_t related information */
static inline pte_t pte_swp_clear_flags(pte_t pte)
{
@@ -64,6 +78,17 @@ static inline pgoff_t swp_offset(swp_entry_t entry)
return entry.val & SWP_OFFSET_MASK;
}
+/*
+ * This should only be called upon a pfn swap entry to get the PFN stored
+ * in the swap entry. Please refers to is_pfn_swap_entry() for definition
+ * of pfn swap entry.
+ */
+static inline unsigned long swp_offset_pfn(swp_entry_t entry)
+{
+ VM_BUG_ON(!is_pfn_swap_entry(entry));
+ return swp_offset(entry) & SWP_PFN_MASK;
+}
+
/* check whether a pte points to a swap entry */
static inline int is_swap_pte(pte_t pte)
{
@@ -369,7 +394,7 @@ static inline int pte_none_mostly(pte_t pte)
static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
{
- struct page *p = pfn_to_page(swp_offset(entry));
+ struct page *p = pfn_to_page(swp_offset_pfn(entry));
/*
* Any use of migration entries may only occur while the
@@ -387,6 +412,9 @@ static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
*/
static inline bool is_pfn_swap_entry(swp_entry_t entry)
{
+ /* Make sure the swp offset can always store the needed fields */
+ BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
+
return is_migration_entry(entry) || is_device_private_entry(entry) ||
is_device_exclusive_entry(entry);
}
@@ -475,11 +503,6 @@ static inline int is_hwpoison_entry(swp_entry_t entry)
return swp_type(entry) == SWP_HWPOISON;
}
-static inline unsigned long hwpoison_entry_to_pfn(swp_entry_t entry)
-{
- return swp_offset(entry);
-}
-
static inline void num_poisoned_pages_inc(void)
{
atomic_long_inc(&num_poisoned_pages);
diff --git a/mm/hmm.c b/mm/hmm.c
index f2aa63b94d9bd..3850fb625dda1 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -253,7 +253,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
cpu_flags = HMM_PFN_VALID;
if (is_writable_device_private_entry(entry))
cpu_flags |= HMM_PFN_WRITE;
- *hmm_pfn = swp_offset(entry) | cpu_flags;
+ *hmm_pfn = swp_offset_pfn(entry) | cpu_flags;
return 0;
}
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 59dd32b753486..e554f9f583ca9 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -635,7 +635,7 @@ static int check_hwpoisoned_entry(pte_t pte, unsigned long addr, short shift,
swp_entry_t swp = pte_to_swp_entry(pte);
if (is_hwpoison_entry(swp))
- pfn = hwpoison_entry_to_pfn(swp);
+ pfn = swp_offset_pfn(swp);
}
if (!pfn || pfn != poisoned_pfn)
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 8e9e574d535aa..93e13fc17d3cb 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -86,7 +86,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
!is_device_exclusive_entry(entry))
return false;
- pfn = swp_offset(entry);
+ pfn = swp_offset_pfn(entry);
} else if (is_swap_pte(*pvmw->pte)) {
swp_entry_t entry;
@@ -96,7 +96,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
!is_device_exclusive_entry(entry))
return false;
- pfn = swp_offset(entry);
+ pfn = swp_offset_pfn(entry);
} else {
if (!pte_present(*pvmw->pte))
return false;
@@ -221,7 +221,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
return not_found(pvmw);
entry = pmd_to_swp_entry(pmde);
if (!is_migration_entry(entry) ||
- !check_pmd(swp_offset(entry), pvmw))
+ !check_pmd(swp_offset_pfn(entry), pvmw))
return not_found(pvmw);
return true;
}