linux-kernel - [RFC 09/11] mm/mmap/vma_merge: convert mergeability checks to return bool

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Date:   Fri, 24 Feb 2023 11:00:20 +0100
From:   Vlastimil Babka <vbabka@...e.cz>
To:     linux-mm@...ck.org, "Liam R. Howlett" <Liam.Howlett@...cle.com>
Cc:     linux-kernel@...r.kernel.org, patches@...ts.linux.dev,
        maple-tree@...ts.infradead.org, Vlastimil Babka <vbabka@...e.cz>
Subject: [RFC 09/11] mm/mmap/vma_merge: convert mergeability checks to return bool

The comments already mention returning 'true' so make the code match
them.

Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
---
 mm/mmap.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 8c2bdf9e3f94..6e439806d4ac 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -744,10 +744,10 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
  * If the vma has a ->close operation then the driver probably needs to release
  * per-vma resources, so we don't attempt to merge those.
  */
-static inline int is_mergeable_vma(struct vm_area_struct *vma,
-				   struct file *file, unsigned long vm_flags,
-				   struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-				   struct anon_vma_name *anon_name)
+static inline bool is_mergeable_vma(struct vm_area_struct *vma,
+				    struct file *file, unsigned long vm_flags,
+				    struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+				    struct anon_vma_name *anon_name)
 {
 	/*
 	 * VM_SOFTDIRTY should not prevent from VMA merging, if we
@@ -758,21 +758,21 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma,
 	 * extended instead.
 	 */
 	if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY)
-		return 0;
+		return false;
 	if (vma->vm_file != file)
-		return 0;
+		return false;
 	if (vma->vm_ops && vma->vm_ops->close)
-		return 0;
+		return false;
 	if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
-		return 0;
+		return false;
 	if (!anon_vma_name_eq(anon_vma_name(vma), anon_name))
-		return 0;
-	return 1;
+		return false;
+	return true;
 }
 
-static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
-					struct anon_vma *anon_vma2,
-					struct vm_area_struct *vma)
+static inline bool is_mergeable_anon_vma(struct anon_vma *anon_vma1,
+					 struct anon_vma *anon_vma2,
+					 struct vm_area_struct *vma)
 {
 	/*
 	 * The list_is_singular() test is to avoid merging VMA cloned from
@@ -780,7 +780,7 @@ static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
 	 */
 	if ((!anon_vma1 || !anon_vma2) && (!vma ||
 		list_is_singular(&vma->anon_vma_chain)))
-		return 1;
+		return true;
 	return anon_vma1 == anon_vma2;
 }
 
@@ -795,7 +795,7 @@ static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
  * indices (16TB on ia32) because do_mmap() does not permit mmap's which
  * wrap, nor mmaps which cover the final page at index -1UL.
  */
-static int
+static bool
 can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
 		     struct anon_vma *anon_vma, struct file *file,
 		     pgoff_t vm_pgoff,
@@ -805,9 +805,9 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
 	if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
 	    is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
 		if (vma->vm_pgoff == vm_pgoff)
-			return 1;
+			return true;
 	}
-	return 0;
+	return false;
 }
 
 /*
@@ -817,7 +817,7 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
  * We cannot merge two vmas if they have differently assigned (non-NULL)
  * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
  */
-static int
+static bool
 can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
 		    struct anon_vma *anon_vma, struct file *file,
 		    pgoff_t vm_pgoff,
@@ -829,9 +829,9 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
 		pgoff_t vm_pglen;
 		vm_pglen = vma_pages(vma);
 		if (vma->vm_pgoff + vm_pglen == vm_pgoff)
-			return 1;
+			return true;
 	}
-	return 0;
+	return false;
 }
 
 /*
-- 
2.39.2