There are straggler invocations of pte_to_swp_entry() lying around, replace
all of these with the software leaf entry equivalent - softleaf_from_pte().

With those removed, eliminate pte_to_swp_entry() altogether.

No functional change intended.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 include/linux/leafops.h |  7 ++++++-
 include/linux/swapops.h | 13 -------------
 mm/debug_vm_pgtable.c   |  2 +-
 mm/internal.h           |  7 +++++--
 mm/memory-failure.c     |  2 +-
 mm/memory.c             | 16 ++++++++--------
 mm/migrate.c            |  2 +-
 mm/mincore.c            |  4 +++-
 mm/rmap.c               |  8 ++++++--
 mm/swapfile.c           | 13 +++++++++++--
 10 files changed, 42 insertions(+), 32 deletions(-)

diff --git a/include/linux/leafops.h b/include/linux/leafops.h
index d282fab866a1..cfafe7a5e7b1 100644
--- a/include/linux/leafops.h
+++ b/include/linux/leafops.h
@@ -54,11 +54,16 @@ static inline softleaf_t softleaf_mk_none(void)
  */
 static inline softleaf_t softleaf_from_pte(pte_t pte)
 {
+	softleaf_t arch_entry;
+
 	if (pte_present(pte) || pte_none(pte))
 		return softleaf_mk_none();
 
+	pte = pte_swp_clear_flags(pte);
+	arch_entry = __pte_to_swp_entry(pte);
+
 	/* Temporary until swp_entry_t eliminated. */
-	return pte_to_swp_entry(pte);
+	return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
 }
 
 /**
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 3d02b288c15e..8cfc966eae48 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -107,19 +107,6 @@ static inline pgoff_t swp_offset(swp_entry_t entry)
 	return entry.val & SWP_OFFSET_MASK;
 }
 
-/*
- * Convert the arch-dependent pte representation of a swp_entry_t into an
- * arch-independent swp_entry_t.
- */
-static inline swp_entry_t pte_to_swp_entry(pte_t pte)
-{
-	swp_entry_t arch_entry;
-
-	pte = pte_swp_clear_flags(pte);
-	arch_entry = __pte_to_swp_entry(pte);
-	return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
-}
-
 /*
  * Convert the arch-independent representation of a swp_entry_t into the
  * arch-dependent pte representation.
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 64db85a80558..1eae87dbef73 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -1229,7 +1229,7 @@ static int __init init_args(struct pgtable_debug_args *args)
 	init_fixed_pfns(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))));
+	max_swap_offset = swp_offset(softleaf_from_pte(softleaf_to_pte(swp_entry(0, ~0UL))));
 	/* Create a swp entry with all possible bits set while still being swap. */
 	args->swp_entry = swp_entry(MAX_SWAPFILES - 1, max_swap_offset);
 	/* Create a non-present migration entry. */
diff --git a/mm/internal.h b/mm/internal.h
index f0c7461bb02c..985605ba3364 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -334,7 +334,7 @@ unsigned int folio_pte_batch(struct folio *folio, pte_t *ptep, pte_t pte,
  */
 static inline pte_t pte_move_swp_offset(pte_t pte, long delta)
 {
-	swp_entry_t entry = pte_to_swp_entry(pte);
+	const softleaf_t entry = softleaf_from_pte(pte);
 	pte_t new = __swp_entry_to_pte(__swp_entry(swp_type(entry),
 						   (swp_offset(entry) + delta)));
 
@@ -389,11 +389,14 @@ static inline int swap_pte_batch(pte_t *start_ptep, int max_nr, pte_t pte)
 
 	cgroup_id = lookup_swap_cgroup_id(entry);
 	while (ptep < end_ptep) {
+		softleaf_t entry;
+
 		pte = ptep_get(ptep);
 
 		if (!pte_same(pte, expected_pte))
 			break;
-		if (lookup_swap_cgroup_id(pte_to_swp_entry(pte)) != cgroup_id)
+		entry = softleaf_from_pte(pte);
+		if (lookup_swap_cgroup_id(entry) != cgroup_id)
 			break;
 		expected_pte = pte_next_swp_offset(expected_pte);
 		ptep++;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 6e79da3de221..ca2204c4647e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -50,7 +50,7 @@
 #include <linux/backing-dev.h>
 #include <linux/migrate.h>
 #include <linux/slab.h>
-#include <linux/swapops.h>
+#include <linux/leafops.h>
 #include <linux/hugetlb.h>
 #include <linux/memory_hotplug.h>
 #include <linux/mm_inline.h>
diff --git a/mm/memory.c b/mm/memory.c
index accd275cd651..f9a2c608aff9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1218,7 +1218,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 	spinlock_t *src_ptl, *dst_ptl;
 	int progress, max_nr, ret = 0;
 	int rss[NR_MM_COUNTERS];
-	swp_entry_t entry = (swp_entry_t){0};
+	softleaf_t entry = softleaf_mk_none();
 	struct folio *prealloc = NULL;
 	int nr;
 
@@ -1282,7 +1282,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 						  dst_vma, src_vma,
 						  addr, rss);
 			if (ret == -EIO) {
-				entry = pte_to_swp_entry(ptep_get(src_pte));
+				entry = softleaf_from_pte(ptep_get(src_pte));
 				break;
 			} else if (ret == -EBUSY) {
 				break;
@@ -4456,13 +4456,13 @@ static struct folio *__alloc_swap_folio(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct folio *folio;
-	swp_entry_t entry;
+	softleaf_t entry;
 
 	folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vmf->address);
 	if (!folio)
 		return NULL;
 
-	entry = pte_to_swp_entry(vmf->orig_pte);
+	entry = softleaf_from_pte(vmf->orig_pte);
 	if (mem_cgroup_swapin_charge_folio(folio, vma->vm_mm,
 					   GFP_KERNEL, entry)) {
 		folio_put(folio);
@@ -4480,7 +4480,7 @@ static struct folio *__alloc_swap_folio(struct vm_fault *vmf)
 static bool can_swapin_thp(struct vm_fault *vmf, pte_t *ptep, int nr_pages)
 {
 	unsigned long addr;
-	swp_entry_t entry;
+	softleaf_t entry;
 	int idx;
 	pte_t pte;
 
@@ -4490,7 +4490,7 @@ static bool can_swapin_thp(struct vm_fault *vmf, pte_t *ptep, int nr_pages)
 
 	if (!pte_same(pte, pte_move_swp_offset(vmf->orig_pte, -idx)))
 		return false;
-	entry = pte_to_swp_entry(pte);
+	entry = softleaf_from_pte(pte);
 	if (swap_pte_batch(ptep, nr_pages, pte) != nr_pages)
 		return false;
 
@@ -4536,7 +4536,7 @@ static struct folio *alloc_swap_folio(struct vm_fault *vmf)
 	unsigned long orders;
 	struct folio *folio;
 	unsigned long addr;
-	swp_entry_t entry;
+	softleaf_t entry;
 	spinlock_t *ptl;
 	pte_t *pte;
 	gfp_t gfp;
@@ -4557,7 +4557,7 @@ static struct folio *alloc_swap_folio(struct vm_fault *vmf)
 	if (!zswap_never_enabled())
 		goto fallback;
 
-	entry = pte_to_swp_entry(vmf->orig_pte);
+	entry = softleaf_from_pte(vmf->orig_pte);
 	/*
 	 * Get a list of all the (large) orders below PMD_ORDER that are enabled
 	 * and suitable for swapping THP.
diff --git a/mm/migrate.c b/mm/migrate.c
index 182a5b7b2ead..c01bc0ddf819 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -534,7 +534,7 @@ void migration_entry_wait_huge(struct vm_area_struct *vma, unsigned long addr, p
 		 * lock release in migration_entry_wait_on_locked().
 		 */
 		hugetlb_vma_unlock_read(vma);
-		migration_entry_wait_on_locked(pte_to_swp_entry(pte), ptl);
+		migration_entry_wait_on_locked(entry, ptl);
 		return;
 	}
 
diff --git a/mm/mincore.c b/mm/mincore.c
index 9a908d8bb706..e5d13eea9234 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -202,7 +202,9 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			for (i = 0; i < step; i++)
 				vec[i] = 1;
 		} else { /* pte is a swap entry */
-			*vec = mincore_swap(pte_to_swp_entry(pte), false);
+			const softleaf_t entry = softleaf_from_pte(pte);
+
+			*vec = mincore_swap(entry, false);
 		}
 		vec += step;
 	}
diff --git a/mm/rmap.c b/mm/rmap.c
index 345466ad396b..d871f2eb821c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1969,7 +1969,9 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 		if (likely(pte_present(pteval))) {
 			pfn = pte_pfn(pteval);
 		} else {
-			pfn = softleaf_to_pfn(pte_to_swp_entry(pteval));
+			const softleaf_t entry = softleaf_from_pte(pteval);
+
+			pfn = softleaf_to_pfn(entry);
 			VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
 		}
 
@@ -2368,7 +2370,9 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
 		if (likely(pte_present(pteval))) {
 			pfn = pte_pfn(pteval);
 		} else {
-			pfn = softleaf_to_pfn(pte_to_swp_entry(pteval));
+			const softleaf_t entry = softleaf_from_pte(pteval);
+
+			pfn = softleaf_to_pfn(entry);
 			VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
 		}
 
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 684f78cd7dd1..e5667a31be9f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3201,8 +3201,17 @@ static int claim_swapfile(struct swap_info_struct *si, struct inode *inode)
  */
 unsigned long generic_max_swapfile_size(void)
 {
-	return swp_offset(pte_to_swp_entry(
-			swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+	swp_entry_t entry = swp_entry(0, ~0UL);
+	const pte_t pte = softleaf_to_pte(entry);
+
+	/*
+	 * Since the PTE can be an invalid softleaf entry (e.g. the none PTE),
+	 * we need to do this manually.
+	 */
+	entry = __pte_to_swp_entry(pte);
+	entry = swp_entry(__swp_type(entry), __swp_offset(entry));
+
+	return swp_offset(entry) + 1;
 }
 
 /* Can be overridden by an architecture for additional checks. */
-- 
2.51.0

On 11/10/25 23:21, Lorenzo Stoakes wrote:
> There are straggler invocations of pte_to_swp_entry() lying around, replace
> all of these with the software leaf entry equivalent - softleaf_from_pte().
> 
> With those removed, eliminate pte_to_swp_entry() altogether.

RIP.

> No functional change intended.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

Impressive work, I hope it can be promoted to mm-stable now. It would be a
pain not to have it merged in the 6.19 merge window. Still plenty of time to
fix up any hypothetical bugs not found until now during the rc's - overall
it looks solid.

Thanks!
Vlastimil

On Thu, Nov 27, 2025 at 06:53:21PM +0100, Vlastimil Babka wrote:
> On 11/10/25 23:21, Lorenzo Stoakes wrote:
> > There are straggler invocations of pte_to_swp_entry() lying around, replace
> > all of these with the software leaf entry equivalent - softleaf_from_pte().
> >
> > With those removed, eliminate pte_to_swp_entry() altogether.
>
> RIP.
>
> > No functional change intended.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
>

Thanks for the review!

> Impressive work, I hope it can be promoted to mm-stable now. It would be a

Thanks.

It's already in mm-stable?

> pain not to have it merged in the 6.19 merge window. Still plenty of time to

I have no idea why it wouldn't be?

> fix up any hypothetical bugs not found until now during the rc's - overall
> it looks solid.

Right yeah. It's been sat in -next for ages. The bug you found (thanks!) must be
pretty hard to hit... even by syzbot!

Maybe there are others, this touches a lot, but obviously that's what rc's are
for. I think you can say the same about literally any other series currently in
mm-stable :)

Please can we in no way delay this. This work is very important in my view and I
intend to base further work upon it in the upcoming cycle.

>
> Thanks!
> Vlastimil

Cheers, Lorenzo

On 11/27/25 18:53, Vlastimil Babka wrote:
> On 11/10/25 23:21, Lorenzo Stoakes wrote:
>> There are straggler invocations of pte_to_swp_entry() lying around, replace
>> all of these with the software leaf entry equivalent - softleaf_from_pte().
>> 
>> With those removed, eliminate pte_to_swp_entry() altogether.
> 
> RIP.
> 
>> No functional change intended.
>> 
>> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> 
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> 
> Impressive work, I hope it can be promoted to mm-stable now. It would be a

Ah made a mistake checking the git branches, so it's in fact in mm-stable
already. Great! Sorry for the noise.

> pain not to have it merged in the 6.19 merge window. Still plenty of time to
> fix up any hypothetical bugs not found until now during the rc's - overall
> it looks solid.
> 
> Thanks!
> Vlastimil