[RFC PATCH] arm: use mmap_write_(un)lock for copy_to_user

[Christian Lamparter]

The way I understand this, the copy_to_user would
require the use of the mmap_*write*_lock variants,
since this functions writes to the user space pages?

Cc: Chris Blake <chrisrblake93 at gmail.com>
Signed-off-by: Christian Lamparter <chunkeey at gmail.com>
---
 arch/arm/lib/uaccess_with_memcpy.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index 106f83a5ea6d..7491c13fdf0e 100644
--- a/arch/arm/lib/uaccess_with_memcpy.c
+++ b/arch/arm/lib/uaccess_with_memcpy.c
@@ -101,7 +101,7 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
 	atomic = faulthandler_disabled();
 
 	if (!atomic)
-		mmap_read_lock(current->mm);
+		mmap_write_lock(current->mm);
 	while (n) {
 		pte_t *pte;
 		spinlock_t *ptl;
@@ -109,11 +109,11 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
 
 		while (!pin_page_for_write(to, &pte, &ptl)) {
 			if (!atomic)
-				mmap_read_unlock(current->mm);
+				mmap_write_unlock(current->mm);
 			if (__put_user(0, (char __user *)to))
 				goto out;
 			if (!atomic)
-				mmap_read_lock(current->mm);
+				mmap_write_lock(current->mm);
 		}
 
 		tocopy = (~(unsigned long)to & ~PAGE_MASK) + 1;
@@ -133,7 +133,7 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
 			spin_unlock(ptl);
 	}
 	if (!atomic)
-		mmap_read_unlock(current->mm);
+		mmap_write_unlock(current->mm);
 
 out:
 	return n;
-- 
2.28.0