[PATCH v3 03/13] mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc

[Lorenzo Stoakes (Oracle)]

There's no need to use the ancient approach of returning an integer here,
just return a boolean.

Also update flush_needed to be a boolean, similarly.

Also add a kdoc comment describing the function.

No functional change intended.

Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Acked-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@xxxxxxxxxx>
---
 include/linux/huge_mm.h |  4 ++--
 mm/huge_memory.c        | 23 ++++++++++++++++-------
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index af726f0aa30d..1258fa37e85b 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -27,8 +27,8 @@ static inline void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
 vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf);
 bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			   pmd_t *pmd, unsigned long addr, unsigned long next);
-int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd,
-		 unsigned long addr);
+bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd,
+		  unsigned long addr);
 int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, pud_t *pud,
 		 unsigned long addr);
 bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4e8df3a35cab..3c9e2ebaacfa 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2325,11 +2325,20 @@ static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd)
 	mm_dec_nr_ptes(mm);
 }
 
-int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
+/**
+ * zap_huge_pmd - Zap a huge THP which is of PMD size.
+ * @tlb: The MMU gather TLB state associated with the operation.
+ * @vma: The VMA containing the range to zap.
+ * @pmd: A pointer to the leaf PMD entry.
+ * @addr: The virtual address for the range to zap.
+ *
+ * Returns: %true on success, %false otherwise.
+ */
+bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		 pmd_t *pmd, unsigned long addr)
 {
 	struct folio *folio = NULL;
-	int flush_needed = 1;
+	bool flush_needed = true;
 	spinlock_t *ptl;
 	pmd_t orig_pmd;
 
@@ -2337,7 +2346,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 
 	ptl = __pmd_trans_huge_lock(pmd, vma);
 	if (!ptl)
-		return 0;
+		return false;
 	/*
 	 * For architectures like ppc64 we look at deposited pgtable
 	 * when calling pmdp_huge_get_and_clear. So do the
@@ -2352,13 +2361,13 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		if (arch_needs_pgtable_deposit())
 			zap_deposited_table(tlb->mm, pmd);
 		spin_unlock(ptl);
-		return 1;
+		return true;
 	}
 	if (is_huge_zero_pmd(orig_pmd)) {
 		if (!vma_is_dax(vma) || arch_needs_pgtable_deposit())
 			zap_deposited_table(tlb->mm, pmd);
 		spin_unlock(ptl);
-		return 1;
+		return true;
 	}
 
 	if (pmd_present(orig_pmd)) {
@@ -2372,7 +2381,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		const softleaf_t entry = softleaf_from_pmd(orig_pmd);
 
 		folio = softleaf_to_folio(entry);
-		flush_needed = 0;
+		flush_needed = false;
 
 		if (!thp_migration_supported())
 			WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
@@ -2406,7 +2415,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 	if (flush_needed)
 		tlb_remove_page_size(tlb, &folio->page, HPAGE_PMD_SIZE);
 
-	return 1;
+	return true;
 }
 
 #ifndef pmd_move_must_withdraw
-- 
2.53.0