[Patch v2 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list

[Wei Yang]

Just make the code a little easy to read.

Signed-off-by: Wei Yang <richardw.y...@linux.intel.com>

---
Note: For nommu part, the code is not tested.

---
v2: rebase on top of 5.4-rc1
---
 mm/internal.h |  1 +
 mm/mmap.c     | 12 +-----------
 mm/nommu.c    |  8 +-------
 mm/util.c     | 14 ++++++++++++++
 4 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 8e596fa8a7de..f93fd474dac3 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -291,6 +291,7 @@ static inline bool is_data_mapping(vm_flags_t flags)
 /* mm/util.c */
 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
                struct vm_area_struct *prev);
+void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma);
 
 #ifdef CONFIG_MMU
 extern long populate_vma_page_range(struct vm_area_struct *vma,
diff --git a/mm/mmap.c b/mm/mmap.c
index 2ca805209c47..3ab5d20289be 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -686,18 +686,8 @@ static __always_inline void __vma_unlink_common(struct 
mm_struct *mm,
                                                struct vm_area_struct *vma,
                                                struct vm_area_struct *ignore)
 {
-       struct vm_area_struct *prev, *next;
-
        vma_rb_erase_ignore(vma, &mm->mm_rb, ignore);
-       next = vma->vm_next;
-       prev = vma->vm_prev;
-       if (prev)
-               prev->vm_next = next;
-       else
-               mm->mmap = next;
-       if (next)
-               next->vm_prev = prev;
-
+       __vma_unlink_list(mm, vma);
        /* Kill the cache */
        vmacache_invalidate(mm);
 }
diff --git a/mm/nommu.c b/mm/nommu.c
index 2bb923210128..21ddf689d4fa 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -673,13 +673,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
        /* remove from the MM's tree and list */
        rb_erase(&vma->vm_rb, &mm->mm_rb);
 
-       if (vma->vm_prev)
-               vma->vm_prev->vm_next = vma->vm_next;
-       else
-               mm->mmap = vma->vm_next;
-
-       if (vma->vm_next)
-               vma->vm_next->vm_prev = vma->vm_prev;
+       __vma_unlink_list(mm, vma);
 }
 
 /*
diff --git a/mm/util.c b/mm/util.c
index 023defd39a0d..988d11e6c17c 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -288,6 +288,20 @@ void __vma_link_list(struct mm_struct *mm, struct 
vm_area_struct *vma,
                next->vm_prev = vma;
 }
 
+void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+       struct vm_area_struct *prev, *next;
+
+       next = vma->vm_next;
+       prev = vma->vm_prev;
+       if (prev)
+               prev->vm_next = next;
+       else
+               mm->mmap = next;
+       if (next)
+               next->vm_prev = prev;
+}
+
 /* Check if the vma is being used as a stack by this task */
 int vma_is_stack_for_current(struct vm_area_struct *vma)
 {
-- 
2.17.1