From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> Subject: mm/mmap: add inline vma_next() for readability of mmap code There are three places that the next vma is required which uses the same block of code. Replace the block with a function and add comments on what happens in the case where NULL is encountered. Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@xxxxxxxxxx Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) --- a/mm/mmap.c~mm-mmap-add-inline-vma_next-for-readability-of-mmap-code +++ a/mm/mmap.c @@ -558,6 +558,23 @@ static int find_vma_links(struct mm_stru return 0; } +/* + * vma_next() - Get the next VMA. + * @mm: The mm_struct. + * @vma: The current vma. + * + * If @vma is NULL, return the first vma in the mm. + * + * Returns: The next VMA after @vma. + */ +static inline struct vm_area_struct *vma_next(struct mm_struct *mm, + struct vm_area_struct *vma) +{ + if (!vma) + return mm->mmap; + + return vma->vm_next; +} static unsigned long count_vma_pages_range(struct mm_struct *mm, unsigned long addr, unsigned long end) { @@ -1128,10 +1145,7 @@ struct vm_area_struct *vma_merge(struct if (vm_flags & VM_SPECIAL) return NULL; - if (prev) - next = prev->vm_next; - else - next = mm->mmap; + next = vma_next(mm, prev); area = next; if (area && area->vm_end == end) /* cases 6, 7, 8 */ next = next->vm_next; @@ -2632,7 +2646,7 @@ static void unmap_region(struct mm_struc struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end) { - struct vm_area_struct *next = prev ? prev->vm_next : mm->mmap; + struct vm_area_struct *next = vma_next(mm, prev); struct mmu_gather tlb; lru_add_drain(); @@ -2831,7 +2845,7 @@ int __do_munmap(struct mm_struct *mm, un if (error) return error; } - vma = prev ? prev->vm_next : mm->mmap; + vma = vma_next(mm, prev); if (unlikely(uf)) { /* _
