On Sat, Sep 19, 2020 at 7:38 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
>
> I'd just keep the native version inline and have the compat one in
> a helper, but that is just a minor detail.
Folded in this change:
diff --git a/mm/migrate.c b/mm/migrate.c
index e9dfbde5f12c..d3fa3f4bf653 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1835,18 +1835,14 @@ static void do_pages_stat_array(struct
mm_struct *mm, unsigned long nr_pages,
mmap_read_unlock(mm);
}
-static int put_pages_array(const void __user *chunk_pages[],
- const void __user * __user *pages,
- unsigned long chunk_nr)
+static int put_compat_pages_array(const void __user *chunk_pages[],
+ const void __user * __user *pages,
+ unsigned long chunk_nr)
{
compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
compat_uptr_t p;
int i;
- if (!in_compat_syscall())
- return copy_from_user(chunk_pages, pages,
- chunk_nr * sizeof(*chunk_pages));
-
for (i = 0; i < chunk_nr; i++) {
if (get_user(p, pages32 + i))
return -EFAULT;
@@ -1875,8 +1871,15 @@ static int do_pages_stat(struct mm_struct *mm,
unsigned long nr_pages,
if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
chunk_nr = DO_PAGES_STAT_CHUNK_NR;
- if (put_pages_array(chunk_pages, pages, chunk_nr))
- break;
+ if (in_compat_syscall()) {
+ if (put_compat_pages_array(chunk_pages, pages,
+ chunk_nr))
+ break;
+ } else {
+ if (copy_from_user(chunk_pages, pages,
+ chunk_nr * sizeof(*chunk_pages)))
+ break;
+ }
do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
It does make the separation cleaner but it's also more code, which is
why I had it in the combined function before.
Arnd
