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authorLiam R. Howlett <Liam.Howlett@Oracle.com>2020-10-17 16:14:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-18 09:27:09 -0700
commitfb8090b699c3e147e5bef8e0008edc3bddc33fad (patch)
tree71825c5cbf6136984c15631ccf4870dd79d7be78 /mm
parent3903b55a6117ee5a8c90108beaf8d921474aa05a (diff)
mm/mmap: add inline munmap_vma_range() for code readability
There are two locations that have a block of code for munmapping a vma range. Change those two locations to use a function and add meaningful comments about what happens to the arguments, which was unclear in the previous code. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c48
1 files changed, 33 insertions, 15 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index b0b8e9e94220..d91ecb00d38c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -575,6 +575,33 @@ static inline struct vm_area_struct *vma_next(struct mm_struct *mm,
return vma->vm_next;
}
+
+/*
+ * munmap_vma_range() - munmap VMAs that overlap a range.
+ * @mm: The mm struct
+ * @start: The start of the range.
+ * @len: The length of the range.
+ * @pprev: pointer to the pointer that will be set to previous vm_area_struct
+ * @rb_link: the rb_node
+ * @rb_parent: the parent rb_node
+ *
+ * Find all the vm_area_struct that overlap from @start to
+ * @end and munmap them. Set @pprev to the previous vm_area_struct.
+ *
+ * Returns: -ENOMEM on munmap failure or 0 on success.
+ */
+static inline int
+munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
+ struct vm_area_struct **pprev, struct rb_node ***link,
+ struct rb_node **parent, struct list_head *uf)
+{
+
+ while (find_vma_links(mm, start, start + len, pprev, link, parent))
+ if (do_munmap(mm, start, len, uf))
+ return -ENOMEM;
+
+ return 0;
+}
static unsigned long count_vma_pages_range(struct mm_struct *mm,
unsigned long addr, unsigned long end)
{
@@ -1721,13 +1748,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
return -ENOMEM;
}
- /* Clear old maps */
- while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
- &rb_parent)) {
- if (do_munmap(mm, addr, len, uf))
- return -ENOMEM;
- }
-
+ /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
+ if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+ return -ENOMEM;
/*
* Private writable mapping: check memory availability
*/
@@ -3063,14 +3086,9 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
if (error)
return error;
- /*
- * Clear old maps. this also does some error checking for us
- */
- while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
- &rb_parent)) {
- if (do_munmap(mm, addr, len, uf))
- return -ENOMEM;
- }
+ /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
+ if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+ return -ENOMEM;
/* Check against address space limits *after* clearing old maps... */
if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))