[PATCH RFC 8/9] mm: call arch-specific swap hooks from generic swap hooks

[Mauricio Faria de Oliveira <mfo@igalia.com>]

Add generic swap hooks that just call the arch-specific ones (e.g., arm64).

Signed-off-by: Mauricio Faria de Oliveira <mfo@igalia.com>
---
 include/linux/pgtable.h | 20 ++++++++++++++++++++
 mm/memory.c             |  2 +-
 mm/page_io.c            |  2 +-
 mm/shmem.c              |  2 +-
 mm/swapfile.c           |  6 +++---
 5 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 652f287c1ef6..23d30afe439e 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1220,6 +1220,26 @@ static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio)
 }
 #endif
 
+static inline int hook_prepare_to_swap(struct folio *folio)
+{
+	return arch_prepare_to_swap(folio);
+}
+
+static inline void hook_swap_invalidate_page(int type, pgoff_t offset)
+{
+	arch_swap_invalidate_page(type, offset);
+}
+
+static inline void hook_swap_invalidate_area(int type)
+{
+	arch_swap_invalidate_area(type);
+}
+
+static inline void hook_swap_restore(swp_entry_t entry, struct folio *folio)
+{
+	arch_swap_restore(entry, folio);
+}
+
 #ifndef __HAVE_ARCH_MOVE_PTE
 #define move_pte(pte, old_addr, new_addr)	(pte)
 #endif
diff --git a/mm/memory.c b/mm/memory.c
index 2a55edc48a65..6a5a5bd3eeed 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4945,7 +4945,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 	 * when reading from swap. This metadata may be indexed by swap entry
 	 * so this must be called before swap_free().
 	 */
-	arch_swap_restore(folio_swap(entry, folio), folio);
+	hook_swap_restore(folio_swap(entry, folio), folio);
 
 	/*
 	 * Remove the swap entry and conditionally try to free up the swapcache.
diff --git a/mm/page_io.c b/mm/page_io.c
index 3c342db77ce3..b62c53a86a59 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -248,7 +248,7 @@ int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug)
 	 * Arch code may have to preserve more data than just the page
 	 * contents, e.g. memory tags.
 	 */
-	ret = arch_prepare_to_swap(folio);
+	ret = hook_prepare_to_swap(folio);
 	if (ret) {
 		folio_mark_dirty(folio);
 		goto out_unlock;
diff --git a/mm/shmem.c b/mm/shmem.c
index 3f194c9842a8..ef53c14156fb 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2395,7 +2395,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
 	 * Some architectures may have to restore extra metadata to the
 	 * folio after reading from swap.
 	 */
-	arch_swap_restore(folio_swap(swap, folio), folio);
+	hook_swap_restore(folio_swap(swap, folio), folio);
 
 	if (shmem_should_replace_folio(folio, gfp)) {
 		error = shmem_replace_folio(&folio, gfp, info, index, vma);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 46d2008e4b99..e156f5cb6e9f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1270,7 +1270,7 @@ static void swap_range_free(struct swap_info_struct *si, unsigned long offset,
 	else
 		swap_slot_free_notify = NULL;
 	while (offset <= end) {
-		arch_swap_invalidate_page(si->type, offset);
+		hook_swap_invalidate_page(si->type, offset);
 		if (swap_slot_free_notify)
 			swap_slot_free_notify(si->bdev, offset);
 		offset++;
@@ -2196,7 +2196,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 	 * when reading from swap. This metadata may be indexed by swap entry
 	 * so this must be called before swap_free().
 	 */
-	arch_swap_restore(folio_swap(entry, folio), folio);
+	hook_swap_restore(folio_swap(entry, folio), folio);
 
 	dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
 	inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
@@ -2931,7 +2931,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 	p->cluster_info = NULL;
 	spin_unlock(&p->lock);
 	spin_unlock(&swap_lock);
-	arch_swap_invalidate_area(p->type);
+	hook_swap_invalidate_area(p->type);
 	zswap_swapoff(p->type);
 	mutex_unlock(&swapon_mutex);
 	kfree(p->global_cluster);
-- 
2.51.0