From: Jeff Mahoney <jeffm@suse.com>
Subject: initramfs-dsdt: Remember to kmap pages

 The original initramfs DSDT patches didn't kmap pages which could have
 resulted in Oopses.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 init/initramfs.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -367,8 +367,9 @@ ssize_t initramfs_file_read(struct file
 			break;
 		}
 
-		data = page_address(page);
+		data = kmap_atomic(page, KM_USER0);
 		memcpy(i.iov->iov_base + i.iov_offset, data + offset, bytes);
+		kunmap_atomic(data);
 
 		iov_iter_advance(&i, bytes);
 		pos += bytes;
@@ -420,13 +421,15 @@ ssize_t initramfs_file_write(struct file
 						&page, &fsdata);
 		if (unlikely(status))
 			break;
-		data = page_address(page);
+		data = kmap_atomic(page, KM_USER0);
 
 		memcpy(data + offset, i.iov->iov_base + i.iov_offset, bytes);
 		copied = bytes;
 
 		status = simple_write_end(file, mapping, pos, bytes, copied,
 						page, fsdata);
+
+		kunmap_atomic(data, KM_USER0);
 		if (unlikely(status < 0))
 			break;
 		copied = status;