[RFC PATCH 02/18] mm/pgtable: convert ptdesc.pmd_huge_pte to ptdesc pointer

[alexs@kernel.org]

From: Alex Shi <alexs@kernel.org>

folio/page.pmd_huge_pte is a pointer to pagetable descriptor: pgtable_t.
In most arch, it is a typedef of 'struct page *'. But we have ptdesc now,
tt's better to convert it to right one: struct ptdesc pointer.

Different from others, s390/sparc use typedef 'pte_t *' as pgtable_t, so
they need different cost in their arch.

Thanks for lkp found the build issue for s390/sparc, it fixed now.

Signed-off-by: Alex Shi <alexs@kernel.org>
Cc: linux-mm@kvack.org
Cc: sparclinux@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox  <willy@infradead.org>
Cc: Mike Rapoport  <rppt@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
---
 arch/s390/mm/pgtable.c   |  6 +++---
 arch/sparc/mm/tlb.c      |  6 +++---
 include/linux/mm_types.h |  4 ++--
 mm/pgtable-generic.c     | 16 ++++++++--------
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 2c944bafb030..201d350abd1e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -574,7 +574,7 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 		INIT_LIST_HEAD(lh);
 	else
 		list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
-	pmd_huge_pte(mm, pmdp) = pgtable;
+	pmd_huge_pte(mm, pmdp) = (struct ptdesc *)pgtable;
 }
 
 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
@@ -586,12 +586,12 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 	assert_spin_locked(pmd_lockptr(mm, pmdp));
 
 	/* FIFO */
-	pgtable = pmd_huge_pte(mm, pmdp);
+	pgtable = (pte_t *)pmd_huge_pte(mm, pmdp);
 	lh = (struct list_head *) pgtable;
 	if (list_empty(lh))
 		pmd_huge_pte(mm, pmdp) = NULL;
 	else {
-		pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
+		pmd_huge_pte(mm, pmdp) = (struct ptdesc *) lh->next;
 		list_del(lh);
 	}
 	ptep = (pte_t *) pgtable;
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 8648a50afe88..903825b4c997 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -278,7 +278,7 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 		INIT_LIST_HEAD(lh);
 	else
 		list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
-	pmd_huge_pte(mm, pmdp) = pgtable;
+	pmd_huge_pte(mm, pmdp) = (struct ptdesc *)pgtable;
 }
 
 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
@@ -289,12 +289,12 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 	assert_spin_locked(&mm->page_table_lock);
 
 	/* FIFO */
-	pgtable = pmd_huge_pte(mm, pmdp);
+	pgtable = (pte_t *)pmd_huge_pte(mm, pmdp);
 	lh = (struct list_head *) pgtable;
 	if (list_empty(lh))
 		pmd_huge_pte(mm, pmdp) = NULL;
 	else {
-		pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
+		pmd_huge_pte(mm, pmdp) = (struct ptdesc *) lh->next;
 		list_del(lh);
 	}
 	pte_val(pgtable[0]) = 0;
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 485424979254..2e3eddf6edc9 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -462,7 +462,7 @@ struct ptdesc {
 		struct list_head pt_list;
 		struct {
 			unsigned long _pt_pad_1;
-			pgtable_t pmd_huge_pte;
+			struct ptdesc *pmd_huge_pte;
 		};
 	};
 	unsigned long __page_mapping;
@@ -948,7 +948,7 @@ struct mm_struct {
 		struct mmu_notifier_subscriptions *notifier_subscriptions;
 #endif
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
-		pgtable_t pmd_huge_pte; /* protected by page_table_lock */
+		struct ptdesc *pmd_huge_pte; /* protected by page_table_lock */
 #endif
 #ifdef CONFIG_NUMA_BALANCING
 		/*
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 2ce714f1dd15..f34a8d115f5b 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -171,8 +171,8 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 	if (!pmd_huge_pte(mm, pmdp))
 		INIT_LIST_HEAD(&pgtable->lru);
 	else
-		list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
-	pmd_huge_pte(mm, pmdp) = pgtable;
+		list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->pt_list);
+	pmd_huge_pte(mm, pmdp) = page_ptdesc(pgtable);
 }
 #endif
 
@@ -180,17 +180,17 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 /* no "address" argument so destroys page coloring of some arch */
 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 {
-	pgtable_t pgtable;
+	struct ptdesc *ptdesc;
 
 	assert_spin_locked(pmd_lockptr(mm, pmdp));
 
 	/* FIFO */
-	pgtable = pmd_huge_pte(mm, pmdp);
-	pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
-							  struct page, lru);
+	ptdesc = pmd_huge_pte(mm, pmdp);
+	pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&ptdesc->pt_list,
+							  struct ptdesc, pt_list);
 	if (pmd_huge_pte(mm, pmdp))
-		list_del(&pgtable->lru);
-	return pgtable;
+		list_del(&ptdesc->pt_list);
+	return ptdesc_page(ptdesc);
 }
 #endif
 
-- 
2.43.0