[RFC PATCH v2 10/15] mm: Allow __pagetable_ctor() to fail

[Kevin Brodsky]

In preparation for adding construction hooks (that may fail) to
__pagetable_ctor(), make __pagetable_ctor() return a bool,
propagate it to pagetable_*_ctor() and handle failure in
the generic {pud,p4d,pgd}_alloc.

Signed-off-by: Kevin Brodsky <kevin.brodsky@xxxxxxx>
---
 include/asm-generic/pgalloc.h | 15 ++++++++++++---
 include/linux/mm.h            | 21 ++++++++++-----------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index 892ece4558a2..9962f7454d0c 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h
@@ -173,7 +173,10 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long
 	if (!ptdesc)
 		return NULL;
 
-	pagetable_pud_ctor(ptdesc);
+	if (!pagetable_pud_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
+		return NULL;
+	}
 	return ptdesc_address(ptdesc);
 }
 #define __pud_alloc_one(...)	alloc_hooks(__pud_alloc_one_noprof(__VA_ARGS__))
@@ -227,7 +230,10 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long
 	if (!ptdesc)
 		return NULL;
 
-	pagetable_p4d_ctor(ptdesc);
+	if (!pagetable_p4d_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
+		return NULL;
+	}
 	return ptdesc_address(ptdesc);
 }
 #define __p4d_alloc_one(...)	alloc_hooks(__p4d_alloc_one_noprof(__VA_ARGS__))
@@ -271,7 +277,10 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order
 	if (!ptdesc)
 		return NULL;
 
-	pagetable_pgd_ctor(ptdesc);
+	if (!pagetable_pgd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
+		return NULL;
+	}
 	return ptdesc_address(ptdesc);
 }
 #define __pgd_alloc(...)	alloc_hooks(__pgd_alloc_noprof(__VA_ARGS__))
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 453a26bcad1a..e99040be477f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3076,12 +3076,13 @@ static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; }
 static inline void ptlock_free(struct ptdesc *ptdesc) {}
 #endif /* defined(CONFIG_SPLIT_PTE_PTLOCKS) */
 
-static inline void __pagetable_ctor(struct ptdesc *ptdesc)
+static inline bool __pagetable_ctor(struct ptdesc *ptdesc)
 {
 	struct folio *folio = ptdesc_folio(ptdesc);
 
 	__folio_set_pgtable(folio);
 	lruvec_stat_add_folio(folio, NR_PAGETABLE);
+	return true;
 }
 
 static inline void pagetable_dtor(struct ptdesc *ptdesc)
@@ -3103,8 +3104,7 @@ static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc)
 {
 	if (!ptlock_init(ptdesc))
 		return false;
-	__pagetable_ctor(ptdesc);
-	return true;
+	return __pagetable_ctor(ptdesc);
 }
 
 pte_t *___pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp);
@@ -3210,8 +3210,7 @@ static inline bool pagetable_pmd_ctor(struct ptdesc *ptdesc)
 	if (!pmd_ptlock_init(ptdesc))
 		return false;
 	ptdesc_pmd_pts_init(ptdesc);
-	__pagetable_ctor(ptdesc);
-	return true;
+	return __pagetable_ctor(ptdesc);
 }
 
 /*
@@ -3233,19 +3232,19 @@ static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud)
 	return ptl;
 }
 
-static inline void pagetable_pud_ctor(struct ptdesc *ptdesc)
+static inline bool pagetable_pud_ctor(struct ptdesc *ptdesc)
 {
-	__pagetable_ctor(ptdesc);
+	return __pagetable_ctor(ptdesc);
 }
 
-static inline void pagetable_p4d_ctor(struct ptdesc *ptdesc)
+static inline bool pagetable_p4d_ctor(struct ptdesc *ptdesc)
 {
-	__pagetable_ctor(ptdesc);
+	return __pagetable_ctor(ptdesc);
 }
 
-static inline void pagetable_pgd_ctor(struct ptdesc *ptdesc)
+static inline bool pagetable_pgd_ctor(struct ptdesc *ptdesc)
 {
-	__pagetable_ctor(ptdesc);
+	return __pagetable_ctor(ptdesc);
 }
 
 extern void __init pagecache_init(void);
-- 
2.47.0