Split out the madvise parameters validation logic from do_madvise(), for
easy reuse of the logic from a future change.
Reviewed-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
mm/madvise.c | 32 ++++++++++++++++++++++----------
1 file changed, 22 insertions(+), 10 deletions(-)
diff --git a/mm/madvise.c b/mm/madvise.c
index df5a87a1846a..efab2878be7c 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1594,6 +1594,27 @@ static void madvise_unlock(struct mm_struct *mm, int behavior)
mmap_read_unlock(mm);
}
+static bool is_valid_madvise(unsigned long start, size_t len_in, int behavior)
+{
+ size_t len;
+
+ if (!madvise_behavior_valid(behavior))
+ return false;
+
+ if (!PAGE_ALIGNED(start))
+ return false;
+ len = PAGE_ALIGN(len_in);
+
+ /* Check to see whether len was rounded up from small -ve to zero */
+ if (len_in && !len)
+ return false;
+
+ if (start + len < start)
+ return false;
+
+ return true;
+}
+
/*
* The madvise(2) system call.
*
@@ -1673,20 +1694,11 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
size_t len;
struct blk_plug plug;
- if (!madvise_behavior_valid(behavior))
+ if (!is_valid_madvise(start, len_in, behavior))
return -EINVAL;
- if (!PAGE_ALIGNED(start))
- return -EINVAL;
len = PAGE_ALIGN(len_in);
-
- /* Check to see whether len was rounded up from small -ve to zero */
- if (len_in && !len)
- return -EINVAL;
-
end = start + len;
- if (end < start)
- return -EINVAL;
if (end == start)
return 0;
--
2.39.5
