Revert "cifs: No need to send SIGKILL to demux_thread during umount"

This reverts commit 52a36244443eabb594bdb63622ff2dd7a083f0e2.

Causes rmmod to fail for at least 7 seconds after unmount which
makes automated testing a little harder when reloading cifs.ko
between test runs.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
CC: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 8a9fded7c135..36ca2045009b 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -837,6 +837,7 @@ cifs_demultiplex_thread(void *p)
         struct TCP_Server_Info *server = p;
         unsigned int pdu_length;
         char *buf = NULL;
+        struct task_struct *task_to_wake = NULL;
         struct mid_q_entry *mid_entry;
 
         current->flags |= PF_MEMALLOC;
@@ -927,7 +928,19 @@ cifs_demultiplex_thread(void *p)
         if (server->smallbuf) /* no sense logging a debug message if NULL */
                 cifs_small_buf_release(server->smallbuf);
 
+        task_to_wake = xchg(&server->tsk, NULL);
         clean_demultiplex_info(server);
+
+        /* if server->tsk was NULL then wait for a signal before exiting */
+        if (!task_to_wake) {
+                set_current_state(TASK_INTERRUPTIBLE);
+                while (!signal_pending(current)) {
+                        schedule();
+                        set_current_state(TASK_INTERRUPTIBLE);
+                }
+                set_current_state(TASK_RUNNING);
+        }
+
         module_put_and_exit(0);
 }
 
@@ -2050,6 +2063,8 @@ cifs_find_tcp_session(struct smb_vol *vol)
 static void
 cifs_put_tcp_session(struct TCP_Server_Info *server)
 {
+        struct task_struct *task;
+
         spin_lock(&cifs_tcp_ses_lock);
         if (--server->srv_count > 0) {
                 spin_unlock(&cifs_tcp_ses_lock);
@@ -2073,6 +2088,10 @@ cifs_put_tcp_session(struct TCP_Server_Info *server)
         kfree(server->session_key.response);
         server->session_key.response = NULL;
         server->session_key.len = 0;
+
+        task = xchg(&server->tsk, NULL);
+        if (task)
+                force_sig(SIGKILL, task);
 }
 
 static struct TCP_Server_Info *