drbd: fix setsockopt for user mode linux

We use our own copy of kernel_setsockopt, and did not mess around with
get_fs/set_fs, since we thought we knew we would always be KERNEL_DS
anyways. Apparently not so for at least user mode linux, so put the
set_fs(KERNEL_DS) in there.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 20 insertions, 13 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 3833d56b8de8..30801922a971 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1484,46 +1484,53 @@ static inline void drbd_flush_workqueue(struct drbd_conf *mdev)
         conn_flush_workqueue(mdev->tconn);
 }
 
-/* yes, there is kernel_setsockopt, but only since 2.6.18. we don't need to
- * mess with get_fs/set_fs, we know we are KERNEL_DS always. */
+/* Yes, there is kernel_setsockopt, but only since 2.6.18.
+ * So we have our own copy of it here. */
 static inline int drbd_setsockopt(struct socket *sock, int level, int optname,
-                        char __user *optval, int optlen)
+                                  char *optval, int optlen)
 {
+        mm_segment_t oldfs = get_fs();
+        char __user *uoptval;
         int err;
+
+        uoptval = (char __user __force *)optval;
+
+        set_fs(KERNEL_DS);
         if (level == SOL_SOCKET)
-                err = sock_setsockopt(sock, level, optname, optval, optlen);
+                err = sock_setsockopt(sock, level, optname, uoptval, optlen);
         else
-                err = sock->ops->setsockopt(sock, level, optname, optval,
+                err = sock->ops->setsockopt(sock, level, optname, uoptval,
                                             optlen);
+        set_fs(oldfs);
         return err;
 }
 
 static inline void drbd_tcp_cork(struct socket *sock)
 {
-        int __user val = 1;
+        int val = 1;
         (void) drbd_setsockopt(sock, SOL_TCP, TCP_CORK,
-                        (char __user *)&val, sizeof(val));
+                        (char*)&val, sizeof(val));
 }
 
 static inline void drbd_tcp_uncork(struct socket *sock)
 {
-        int __user val = 0;
+        int val = 0;
         (void) drbd_setsockopt(sock, SOL_TCP, TCP_CORK,
-                        (char __user *)&val, sizeof(val));
+                        (char*)&val, sizeof(val));
 }
 
 static inline void drbd_tcp_nodelay(struct socket *sock)
 {
-        int __user val = 1;
+        int val = 1;
         (void) drbd_setsockopt(sock, SOL_TCP, TCP_NODELAY,
-                        (char __user *)&val, sizeof(val));
+                        (char*)&val, sizeof(val));
 }
 
 static inline void drbd_tcp_quickack(struct socket *sock)
 {
-        int __user val = 2;
+        int val = 2;
         (void) drbd_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
-                        (char __user *)&val, sizeof(val));
+                        (char*)&val, sizeof(val));
 }
 
 void drbd_bump_write_ordering(struct drbd_conf *mdev, enum write_ordering_e wo);