--- /dev/null
+From 97fbfef6bd597888485b653175fb846c6998b60c Mon Sep 17 00:00:00 2001
+From: Shuxiao Zhang <zhangshuxiao@xiaomi.com>
+Date: Thu, 6 Apr 2017 22:30:29 +0800
+Subject: staging: android: ashmem: lseek failed due to no FMODE_LSEEK.
+
+From: Shuxiao Zhang <zhangshuxiao@xiaomi.com>
+
+commit 97fbfef6bd597888485b653175fb846c6998b60c upstream.
+
+vfs_llseek will check whether the file mode has
+FMODE_LSEEK, no return failure. But ashmem can be
+lseek, so add FMODE_LSEEK to ashmem file.
+
+Comment From Greg Hackmann:
+ ashmem_llseek() passes the llseek() call through to the backing
+ shmem file. 91360b02ab48 ("ashmem: use vfs_llseek()") changed
+ this from directly calling the file's llseek() op into a VFS
+ layer call. This also adds a check for the FMODE_LSEEK bit, so
+ without that bit ashmem_llseek() now always fails with -ESPIPE.
+
+Fixes: 91360b02ab48 ("ashmem: use vfs_llseek()")
+Signed-off-by: Shuxiao Zhang <zhangshuxiao@xiaomi.com>
+Tested-by: Greg Hackmann <ghackmann@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/staging/android/ashmem.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/drivers/staging/android/ashmem.c
++++ b/drivers/staging/android/ashmem.c
+@@ -392,6 +392,7 @@ static int ashmem_mmap(struct file *file
+ ret = PTR_ERR(vmfile);
+ goto out;
+ }
++ vmfile->f_mode |= FMODE_LSEEK;
+ asma->file = vmfile;
+ }
+ get_file(asma->file);