[PATCH 4/8] mm/internal: rename swap offset helpers to softleaf offset

[Dev Jain <dev.jain@arm.com>]

In preparation for adding a helper to set softleaf ptes in one go,
generalize the swap entry helpers shifting the swap offset by delta,
for softleaves.

Note that the soft-dirty bit, exclusive bit and uffd bit preservation
will still work for non-swap softleaves, since a softleaf entry is
constructed out of a type and offset, and those bits are ahead of
the soft-dirty, exclusive and uffd bits.

For example, for a migration entry, pte_swp_exclusive() will return
false, as the exclusivity is encoded in the type itself
(SOFTLEAF_MIGRATION_READ_EXCLUSIVE).

Signed-off-by: Dev Jain <dev.jain@arm.com>
---
 mm/internal.h | 29 +++++++++++++++--------------
 mm/memory.c   |  4 ++--
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 51ee4c1310908..ce52188a8a65d 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -475,16 +475,16 @@ unsigned int folio_pte_batch(struct folio *folio, pte_t *ptep, pte_t pte,
 		unsigned int max_nr);
 
 /**
- * pte_move_swp_offset - Move the swap entry offset field of a swap pte
- *	 forward or backward by delta
- * @pte: The initial pte state; must be a swap entry
+ * pte_move_softleaf_offset - Move the softleaf entry offset field of a
+ * softleaf pte forward or backward by delta
+ * @pte: The initial pte state; must be a softleaf entry
  * @delta: The direction and the offset we are moving; forward if delta
  *	 is positive; backward if delta is negative
  *
- * Moves the swap offset, while maintaining all other fields, including
- * swap type, and any swp pte bits. The resulting pte is returned.
+ * Moves the softleaf offset, while maintaining all other fields, including
+ * softleaf type, and any softleaf pte bits. The resulting pte is returned.
  */
-static inline pte_t pte_move_swp_offset(pte_t pte, long delta)
+static inline pte_t pte_move_softleaf_offset(pte_t pte, long delta)
 {
 	const softleaf_t entry = softleaf_from_pte(pte);
 	pte_t new = __swp_entry_to_pte(__swp_entry(swp_type(entry),
@@ -502,15 +502,16 @@ static inline pte_t pte_move_swp_offset(pte_t pte, long delta)
 
 
 /**
- * pte_next_swp_offset - Increment the swap entry offset field of a swap pte.
- * @pte: The initial pte state; must be a swap entry.
+ * pte_next_softleaf_offset - Increment the softleaf entry offset field of a
+ * non-present pte.
+ * @pte: The initial pte state; must be a softleaf entry.
  *
- * Increments the swap offset, while maintaining all other fields, including
- * swap type, and any swp pte bits. The resulting pte is returned.
+ * Increments the softleaf offset, while maintaining all other fields, including
+ * softleaf type, and any softleaf pte bits. The resulting pte is returned.
  */
-static inline pte_t pte_next_swp_offset(pte_t pte)
+static inline pte_t pte_next_softleaf_offset(pte_t pte)
 {
-	return pte_move_swp_offset(pte, 1);
+	return pte_move_softleaf_offset(pte, 1);
 }
 
 /**
@@ -530,7 +531,7 @@ static inline pte_t pte_next_swp_offset(pte_t pte)
  */
 static inline int swap_pte_batch(pte_t *start_ptep, int max_nr, pte_t pte)
 {
-	pte_t expected_pte = pte_next_swp_offset(pte);
+	pte_t expected_pte = pte_next_softleaf_offset(pte);
 	const pte_t *end_ptep = start_ptep + max_nr;
 	pte_t *ptep = start_ptep + 1;
 
@@ -542,7 +543,7 @@ static inline int swap_pte_batch(pte_t *start_ptep, int max_nr, pte_t pte)
 
 		if (!pte_same(pte, expected_pte))
 			break;
-		expected_pte = pte_next_swp_offset(expected_pte);
+		expected_pte = pte_next_softleaf_offset(expected_pte);
 		ptep++;
 	}
 
diff --git a/mm/memory.c b/mm/memory.c
index d88df15018268..7a8442fda0b51 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4753,7 +4753,7 @@ static bool can_swapin_thp(struct vm_fault *vmf, pte_t *ptep, int nr_pages)
 	idx = (vmf->address - addr) / PAGE_SIZE;
 	pte = ptep_get(ptep);
 
-	if (!pte_same(pte, pte_move_swp_offset(vmf->orig_pte, -idx)))
+	if (!pte_same(pte, pte_move_softleaf_offset(vmf->orig_pte, -idx)))
 		return false;
 	/*
 	 * swap_read_folio() can't handle the case a large folio is hybridly
@@ -5062,7 +5062,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 
 		folio_ptep = vmf->pte - idx;
 		folio_pte = ptep_get(folio_ptep);
-		if (!pte_same(folio_pte, pte_move_swp_offset(vmf->orig_pte, -idx)) ||
+		if (!pte_same(folio_pte, pte_move_softleaf_offset(vmf->orig_pte, -idx)) ||
 		    swap_pte_batch(folio_ptep, nr, folio_pte) != nr)
 			goto check_folio;
 
-- 
2.43.0