[PATCH 13/16] mm: remove non_swap_entry() and use leaf entry helpers instead

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

There is simply no need for the hugely confusing concept of 'non-swap' swap
entries now we have the concept of leaf entries and relevant leafent_xxx()
helpers.

Adjust all callers to use these instead and remove non_swap_entry()
altogether.

No functional change intended.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 arch/s390/mm/gmap_helpers.c | 18 +++++++++---------
 arch/s390/mm/pgtable.c      | 12 ++++++------
 fs/proc/task_mmu.c          | 12 ++++++------
 include/linux/swapops.h     |  5 -----
 mm/filemap.c                |  2 +-
 mm/hmm.c                    | 16 ++++++++--------
 mm/madvise.c                |  2 +-
 mm/memory.c                 | 36 ++++++++++++++++++------------------
 mm/mincore.c                |  2 +-
 mm/userfaultfd.c            | 24 ++++++++++++------------
 10 files changed, 62 insertions(+), 67 deletions(-)

diff --git a/arch/s390/mm/gmap_helpers.c b/arch/s390/mm/gmap_helpers.c
index d4c3c36855e2..0cf856f38ade 100644
--- a/arch/s390/mm/gmap_helpers.c
+++ b/arch/s390/mm/gmap_helpers.c
@@ -11,27 +11,27 @@
 #include <linux/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/swap.h>
-#include <linux/swapops.h>
+#include <linux/leafops.h>
 #include <linux/pagewalk.h>
 #include <linux/ksm.h>
 #include <asm/gmap_helpers.h>
 #include <asm/pgtable.h>
 
 /**
- * ptep_zap_swap_entry() - discard a swap entry.
+ * ptep_zap_leaf_entry() - discard a leaf entry.
  * @mm: the mm
- * @entry: the swap entry that needs to be zapped
+ * @entry: the leaf entry that needs to be zapped
  *
- * Discards the given swap entry. If the swap entry was an actual swap
+ * Discards the given leaf entry. If the leaf entry was an actual swap
  * entry (and not a migration entry, for example), the actual swapped
  * page is also discarded from swap.
  */
-static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
+static void ptep_zap_leaf_entry(struct mm_struct *mm, leaf_entry_t entry)
 {
-	if (!non_swap_entry(entry))
+	if (leafent_is_swap(entry))
 		dec_mm_counter(mm, MM_SWAPENTS);
-	else if (is_migration_entry(entry))
-		dec_mm_counter(mm, mm_counter(pfn_swap_entry_folio(entry)));
+	else if (leafent_is_migration(entry))
+		dec_mm_counter(mm, mm_counter(leafent_to_folio(entry)));
 	free_swap_and_cache(entry);
 }
 
@@ -66,7 +66,7 @@ void gmap_helper_zap_one_page(struct mm_struct *mm, unsigned long vmaddr)
 		preempt_disable();
 		pgste = pgste_get_lock(ptep);
 
-		ptep_zap_swap_entry(mm, pte_to_swp_entry(*ptep));
+		ptep_zap_leaf_entry(mm, leafent_from_pte(*ptep));
 		pte_clear(mm, vmaddr, ptep);
 
 		pgste_set_unlock(ptep, pgste);
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 0fde20bbc50b..7805c5a3755e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -16,7 +16,7 @@
 #include <linux/spinlock.h>
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
-#include <linux/swapops.h>
+#include <linux/leafops.h>
 #include <linux/sysctl.h>
 #include <linux/ksm.h>
 #include <linux/mman.h>
@@ -683,12 +683,12 @@ void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
 	pgste_set_unlock(ptep, pgste);
 }
 
-static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
+static void ptep_zap_leaf_entry(struct mm_struct *mm, leaf_entry_t entry)
 {
-	if (!non_swap_entry(entry))
+	if (leafent_is_swap(entry))
 		dec_mm_counter(mm, MM_SWAPENTS);
-	else if (is_migration_entry(entry)) {
-		struct folio *folio = pfn_swap_entry_folio(entry);
+	else if (leafent_is_migration(entry)) {
+		const struct folio *folio = leafent_to_folio(entry);
 
 		dec_mm_counter(mm, mm_counter(folio));
 	}
@@ -710,7 +710,7 @@ void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
 	if (!reset && pte_swap(pte) &&
 	    ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
 	     (pgstev & _PGSTE_GPS_ZERO))) {
-		ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
+		ptep_zap_leaf_entry(mm, leafent_from_pte(pte));
 		pte_clear(mm, addr, ptep);
 	}
 	if (reset)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 0ccdc21e60e0..1df735d6b938 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1020,13 +1020,13 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 	} else if (pte_none(ptent)) {
 		smaps_pte_hole_lookup(addr, walk);
 	} else {
-		swp_entry_t swpent = pte_to_swp_entry(ptent);
+		const leaf_entry_t entry = leafent_from_pte(ptent);
 
-		if (!non_swap_entry(swpent)) {
+		if (leafent_is_swap(entry)) {
 			int mapcount;
 
 			mss->swap += PAGE_SIZE;
-			mapcount = swp_swapcount(swpent);
+			mapcount = swp_swapcount(entry);
 			if (mapcount >= 2) {
 				u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
 
@@ -1035,10 +1035,10 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 			} else {
 				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
 			}
-		} else if (is_pfn_swap_entry(swpent)) {
-			if (is_device_private_entry(swpent))
+		} else if (leafent_has_pfn(entry)) {
+			if (leafent_is_device_private(entry))
 				present = true;
-			page = pfn_swap_entry_to_page(swpent);
+			page = leafent_to_page(entry);
 		}
 	}
 
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 41cfc6d59054..c8e6f927da48 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -492,10 +492,5 @@ static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
 
 #endif  /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
 
-static inline int non_swap_entry(swp_entry_t entry)
-{
-	return swp_type(entry) >= MAX_SWAPFILES;
-}
-
 #endif /* CONFIG_MMU */
 #endif /* _LINUX_SWAPOPS_H */
diff --git a/mm/filemap.c b/mm/filemap.c
index eb1f994291d8..980ea9f20993 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -4566,7 +4566,7 @@ static void filemap_cachestat(struct address_space *mapping,
 				swp_entry_t swp = radix_to_swp_entry(folio);
 
 				/* swapin error results in poisoned entry */
-				if (non_swap_entry(swp))
+				if (!leafent_is_swap(swp))
 					goto resched;
 
 				/*
diff --git a/mm/hmm.c b/mm/hmm.c
index cbcabc48974f..831ef855a55a 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -253,17 +253,17 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
 	}
 
 	if (!pte_present(pte)) {
-		swp_entry_t entry = pte_to_swp_entry(pte);
+		const leaf_entry_t entry = leafent_from_pte(pte);
 
 		/*
 		 * Don't fault in device private pages owned by the caller,
 		 * just report the PFN.
 		 */
-		if (is_device_private_entry(entry) &&
-		    page_pgmap(pfn_swap_entry_to_page(entry))->owner ==
+		if (leafent_is_device_private(entry) &&
+		    page_pgmap(leafent_to_page(entry))->owner ==
 		    range->dev_private_owner) {
 			cpu_flags = HMM_PFN_VALID;
-			if (is_writable_device_private_entry(entry))
+			if (leafent_is_device_private_write(entry))
 				cpu_flags |= HMM_PFN_WRITE;
 			new_pfn_flags = swp_offset_pfn(entry) | cpu_flags;
 			goto out;
@@ -274,16 +274,16 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
 		if (!required_fault)
 			goto out;
 
-		if (!non_swap_entry(entry))
+		if (leafent_is_swap(entry))
 			goto fault;
 
-		if (is_device_private_entry(entry))
+		if (leafent_is_device_private(entry))
 			goto fault;
 
-		if (is_device_exclusive_entry(entry))
+		if (leafent_is_device_exclusive(entry))
 			goto fault;
 
-		if (is_migration_entry(entry)) {
+		if (leafent_is_migration(entry)) {
 			pte_unmap(ptep);
 			hmm_vma_walk->last = addr;
 			migration_entry_wait(walk->mm, pmdp, addr);
diff --git a/mm/madvise.c b/mm/madvise.c
index 900f0f29e77b..67bdfcb315b3 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -249,7 +249,7 @@ static void shmem_swapin_range(struct vm_area_struct *vma,
 			continue;
 		entry = radix_to_swp_entry(folio);
 		/* There might be swapin error entries in shmem mapping. */
-		if (non_swap_entry(entry))
+		if (!leafent_is_swap(entry))
 			continue;
 
 		addr = vma->vm_start +
diff --git a/mm/memory.c b/mm/memory.c
index 1412fc84172d..3d118618bdeb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -932,7 +932,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	struct folio *folio;
 	struct page *page;
 
-	if (likely(!non_swap_entry(entry))) {
+	if (likely(leafent_is_swap(entry))) {
 		if (swap_duplicate(entry) < 0)
 			return -EIO;
 
@@ -950,12 +950,12 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 			set_pte_at(src_mm, addr, src_pte, pte);
 		}
 		rss[MM_SWAPENTS]++;
-	} else if (is_migration_entry(entry)) {
-		folio = pfn_swap_entry_folio(entry);
+	} else if (leafent_is_migration(entry)) {
+		folio = leafent_to_folio(entry);
 
 		rss[mm_counter(folio)]++;
 
-		if (!is_readable_migration_entry(entry) &&
+		if (!leafent_is_migration_read(entry) &&
 				is_cow_mapping(vm_flags)) {
 			/*
 			 * COW mappings require pages in both parent and child
@@ -964,15 +964,15 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 			 */
 			entry = make_readable_migration_entry(
 							swp_offset(entry));
-			pte = swp_entry_to_pte(entry);
+			pte = leafent_to_pte(entry);
 			if (pte_swp_soft_dirty(orig_pte))
 				pte = pte_swp_mksoft_dirty(pte);
 			if (pte_swp_uffd_wp(orig_pte))
 				pte = pte_swp_mkuffd_wp(pte);
 			set_pte_at(src_mm, addr, src_pte, pte);
 		}
-	} else if (is_device_private_entry(entry)) {
-		page = pfn_swap_entry_to_page(entry);
+	} else if (leafent_is_device_private(entry)) {
+		page = leafent_to_page(entry);
 		folio = page_folio(page);
 
 		/*
@@ -996,7 +996,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		 * when a device driver is involved (you cannot easily
 		 * save and restore device driver state).
 		 */
-		if (is_writable_device_private_entry(entry) &&
+		if (leafent_is_device_private_write(entry) &&
 		    is_cow_mapping(vm_flags)) {
 			entry = make_readable_device_private_entry(
 							swp_offset(entry));
@@ -1005,7 +1005,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 				pte = pte_swp_mkuffd_wp(pte);
 			set_pte_at(src_mm, addr, src_pte, pte);
 		}
-	} else if (is_device_exclusive_entry(entry)) {
+	} else if (leafent_is_device_exclusive(entry)) {
 		/*
 		 * Make device exclusive entries present by restoring the
 		 * original entry then copying as for a present pte. Device
@@ -4635,7 +4635,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 	rmap_t rmap_flags = RMAP_NONE;
 	bool need_clear_cache = false;
 	bool exclusive = false;
-	swp_entry_t entry;
+	leaf_entry_t entry;
 	pte_t pte;
 	vm_fault_t ret = 0;
 	void *shadow = NULL;
@@ -4647,15 +4647,15 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 	if (!pte_unmap_same(vmf))
 		goto out;
 
-	entry = pte_to_swp_entry(vmf->orig_pte);
-	if (unlikely(non_swap_entry(entry))) {
-		if (is_migration_entry(entry)) {
+	entry = leafent_from_pte(vmf->orig_pte);
+	if (unlikely(!leafent_is_swap(entry))) {
+		if (leafent_is_migration(entry)) {
 			migration_entry_wait(vma->vm_mm, vmf->pmd,
 					     vmf->address);
-		} else if (is_device_exclusive_entry(entry)) {
-			vmf->page = pfn_swap_entry_to_page(entry);
+		} else if (leafent_is_device_exclusive(entry)) {
+			vmf->page = leafent_to_page(entry);
 			ret = remove_device_exclusive_entry(vmf);
-		} else if (is_device_private_entry(entry)) {
+		} else if (leafent_is_device_private(entry)) {
 			if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
 				/*
 				 * migrate_to_ram is not yet ready to operate
@@ -4666,7 +4666,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 				goto out;
 			}
 
-			vmf->page = pfn_swap_entry_to_page(entry);
+			vmf->page = leafent_to_page(entry);
 			vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
 					vmf->address, &vmf->ptl);
 			if (unlikely(!vmf->pte ||
@@ -4690,7 +4690,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 			} else {
 				pte_unmap_unlock(vmf->pte, vmf->ptl);
 			}
-		} else if (is_hwpoison_entry(entry)) {
+		} else if (leafent_is_hwpoison(entry)) {
 			ret = VM_FAULT_HWPOISON;
 		} else if (leafent_is_marker(entry)) {
 			ret = handle_pte_marker(vmf);
diff --git a/mm/mincore.c b/mm/mincore.c
index e77c5bc88fc7..a1f48df5564e 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -74,7 +74,7 @@ static unsigned char mincore_swap(swp_entry_t entry, bool shmem)
 	 * absent. Page table may contain migration or hwpoison
 	 * entries which are always uptodate.
 	 */
-	if (non_swap_entry(entry))
+	if (!leafent_is_swap(entry))
 		return !shmem;
 
 	/*
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 055ec1050776..d11fa8eeaef2 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1256,7 +1256,6 @@ static long move_pages_ptes(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd
 			    unsigned long dst_addr, unsigned long src_addr,
 			    unsigned long len, __u64 mode)
 {
-	swp_entry_t entry;
 	struct swap_info_struct *si = NULL;
 	pte_t orig_src_pte, orig_dst_pte;
 	pte_t src_folio_pte;
@@ -1430,19 +1429,20 @@ static long move_pages_ptes(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd
 					orig_dst_pte, orig_src_pte, dst_pmd,
 					dst_pmdval, dst_ptl, src_ptl, &src_folio,
 					len);
-	} else {
+	} else { /* !pte_present() */
 		struct folio *folio = NULL;
+		const leaf_entry_t entry = leafent_from_pte(orig_src_pte);
 
-		entry = pte_to_swp_entry(orig_src_pte);
-		if (non_swap_entry(entry)) {
-			if (is_migration_entry(entry)) {
-				pte_unmap(src_pte);
-				pte_unmap(dst_pte);
-				src_pte = dst_pte = NULL;
-				migration_entry_wait(mm, src_pmd, src_addr);
-				ret = -EAGAIN;
-			} else
-				ret = -EFAULT;
+		if (leafent_is_migration(entry)) {
+			pte_unmap(src_pte);
+			pte_unmap(dst_pte);
+			src_pte = dst_pte = NULL;
+			migration_entry_wait(mm, src_pmd, src_addr);
+
+			ret = -EAGAIN;
+			goto out;
+		} else if (!leafent_is_swap(entry)) {
+			ret = -EFAULT;
 			goto out;
 		}
 
-- 
2.51.0