Replace invocations of is_swap_pte() with get_pte_swap_entry() in
mm/debug_vm_pgtable.c.

We update the test code to use a 'true' swap entry throughout so we are
guaranteed this is not a non-swap entry, so all asserts continue to operate
correctly.

With this change in place, we no longer use is_swap_pte() anywhere, so
remove it.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 include/linux/swapops.h |  6 ------
 mm/debug_vm_pgtable.c   | 18 +++++++++---------
 2 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index a557b0e7f05c..728e27e834be 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -120,12 +120,6 @@ static inline unsigned long swp_offset_pfn(swp_entry_t 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)
-{
-	return !pte_none(pte) && !pte_present(pte);
-}
-
 /*
  * Convert the arch-dependent pte representation of a swp_entry_t into an
  * arch-independent swp_entry_t.
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 830107b6dd08..d4b2835569ce 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -701,13 +701,14 @@ static void __init pte_soft_dirty_tests(struct pgtable_debug_args *args)
 static void __init pte_swap_soft_dirty_tests(struct pgtable_debug_args *args)
 {
 	pte_t pte;
+	swp_entry_t entry;
 
 	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 		return;
 
 	pr_debug("Validating PTE swap soft dirty\n");
 	pte = swp_entry_to_pte(args->swp_entry);
-	WARN_ON(!is_swap_pte(pte));
+	WARN_ON(!get_pte_swap_entry(pte, &entry));
 
 	WARN_ON(!pte_swp_soft_dirty(pte_swp_mksoft_dirty(pte)));
 	WARN_ON(pte_swp_soft_dirty(pte_swp_clear_soft_dirty(pte)));
@@ -763,20 +764,18 @@ static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args)
 
 	pte = swp_entry_to_pte(entry);
 	WARN_ON(pte_swp_exclusive(pte));
-	WARN_ON(!is_swap_pte(pte));
-	entry2 = pte_to_swp_entry(pte);
+	WARN_ON(!get_pte_swap_entry(pte, &entry2));
 	WARN_ON(memcmp(&entry, &entry2, sizeof(entry)));
 
 	pte = pte_swp_mkexclusive(pte);
 	WARN_ON(!pte_swp_exclusive(pte));
-	WARN_ON(!is_swap_pte(pte));
+	WARN_ON(!get_pte_swap_entry(pte, &entry2));
 	WARN_ON(pte_swp_soft_dirty(pte));
-	entry2 = pte_to_swp_entry(pte);
 	WARN_ON(memcmp(&entry, &entry2, sizeof(entry)));
 
 	pte = pte_swp_clear_exclusive(pte);
 	WARN_ON(pte_swp_exclusive(pte));
-	WARN_ON(!is_swap_pte(pte));
+	WARN_ON(!get_pte_swap_entry(pte, &entry2));
 	entry2 = pte_to_swp_entry(pte);
 	WARN_ON(memcmp(&entry, &entry2, sizeof(entry)));
 }
@@ -784,11 +783,12 @@ static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args)
 static void __init pte_swap_tests(struct pgtable_debug_args *args)
 {
 	swp_entry_t arch_entry;
+	swp_entry_t entry;
 	pte_t pte1, pte2;
 
 	pr_debug("Validating PTE swap\n");
 	pte1 = swp_entry_to_pte(args->swp_entry);
-	WARN_ON(!is_swap_pte(pte1));
+	WARN_ON(!get_pte_swap_entry(pte1, &entry));
 
 	arch_entry = __pte_to_swp_entry(pte1);
 	pte2 = __swp_entry_to_pte(arch_entry);
@@ -1205,8 +1205,8 @@ static int __init init_args(struct pgtable_debug_args *args)
 
 	/* See generic_max_swapfile_size(): probe the maximum offset */
 	max_swap_offset = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0, ~0UL))));
-	/* Create a swp entry with all possible bits set */
-	args->swp_entry = swp_entry((1 << MAX_SWAPFILES_SHIFT) - 1, max_swap_offset);
+	/* Create a swp entry with all possible bits set while still being swap. */
+	args->swp_entry = swp_entry(MAX_SWAPFILES - 1, max_swap_offset);
 
 	/*
 	 * Allocate (huge) pages because some of the tests need to access
-- 
2.51.0