commit de7675b291d7a01c34652fab35b6e4f9ea7c47fa
author Daniel Rosenberg <drosen@google.com> Wed Jul 19 17:16:43 2017 -0700
committer Daniel Rosenberg <drosen@google.com> Thu Jul 20 22:24:22 2017 +0000
tree aff7e397d7cee76fc67b5bb3840dd3b1a1c6e9f6
parent ecd972d4f9b5868d40ed0e4ee37943816f27f537

ANDROID: sdcardfs: Remove unnecessary lock

The mmap_sem lock does not appear to be protecting
anything, and has been removed in Samsung's more
recent versions of sdcardfs.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: I76ff3e33002716b8384fc8be368028ed63dffe4e
Bug: 63785372

fs/sdcardfs/inode.c

diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index d48da41..683b492 100644
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -773,13 +773,9 @@
 	 * afterwards in the other cases: we fsstack_copy_inode_size from
 	 * the lower level.
 	 */
-	if (current->mm)
-		down_write(&current->mm->mmap_sem);
 	if (ia->ia_valid & ATTR_SIZE) {
 		err = inode_newsize_ok(&tmp, ia->ia_size);
 		if (err) {
-			if (current->mm)
-				up_write(&current->mm->mmap_sem);
 			goto out;
 		}
 		truncate_setsize(inode, ia->ia_size);
@@ -802,8 +798,6 @@
 	err = notify_change2(lower_mnt, lower_dentry, &lower_ia, /* note: lower_ia */
 			NULL);
 	inode_unlock(d_inode(lower_dentry));
-	if (current->mm)
-		up_write(&current->mm->mmap_sem);
 	if (err)
 		goto out;