RE: [PATCH v3 2/4] mm: simplify compat_sys_move_pages

Sent: 17 May 2021 21:34

The compat move_pages() implementation uses compat_alloc_user_space()
for converting the pointer array. Moving the compat handling into
the function itself is a bit simpler and lets us avoid the
compat_alloc_user_space() call.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/migrate.c | 45 ++++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index b234c3f3acb7..a68d07f19a1a 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c

@@ -1855,6 +1855,23 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
 	mmap_read_unlock(mm);
 }

+static int put_compat_pages_array(const void __user *chunk_pages[],
+				  const void __user * __user *pages,
+				  unsigned long chunk_nr)
+{