nfsd: fix a warning in __cld_pipe_upcall()

__cld_pipe_upcall() emits a "do not call blocking ops when
!TASK_RUNNING" warning due to the dput() call in rpc_queue_upcall().
Fix it by using a completion instead of hand coding the wait.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 6 insertions, 11 deletions

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 9c247fa1e959..5188f9f70c78 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -662,7 +662,7 @@ struct cld_net {
 struct cld_upcall {
         struct list_head         cu_list;
         struct cld_net          *cu_net;
-        struct task_struct      *cu_task;
+        struct completion        cu_done;
         struct cld_msg           cu_msg;
 };
 
@@ -671,23 +671,18 @@ __cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)
 {
         int ret;
         struct rpc_pipe_msg msg;
+        struct cld_upcall *cup = container_of(cmsg, struct cld_upcall, cu_msg);
 
         memset(&msg, 0, sizeof(msg));
         msg.data = cmsg;
         msg.len = sizeof(*cmsg);
 
-        /*
-         * Set task state before we queue the upcall. That prevents
-         * wake_up_process in the downcall from racing with schedule.
-         */
-        set_current_state(TASK_UNINTERRUPTIBLE);
         ret = rpc_queue_upcall(pipe, &msg);
         if (ret < 0) {
-                set_current_state(TASK_RUNNING);
                 goto out;
         }
 
-        schedule();
+        wait_for_completion(&cup->cu_done);
 
         if (msg.errno < 0)
                 ret = msg.errno;
@@ -754,7 +749,7 @@ cld_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
         if (copy_from_user(&cup->cu_msg, src, mlen) != 0)
                 return -EFAULT;
 
-        wake_up_process(cup->cu_task);
+        complete(&cup->cu_done);
         return mlen;
 }
 
@@ -769,7 +764,7 @@ cld_pipe_destroy_msg(struct rpc_pipe_msg *msg)
         if (msg->errno >= 0)
                 return;
 
-        wake_up_process(cup->cu_task);
+        complete(&cup->cu_done);
 }
 
 static const struct rpc_pipe_ops cld_upcall_ops = {
@@ -900,7 +895,7 @@ restart_search:
                         goto restart_search;
                 }
         }
-        new->cu_task = current;
+        init_completion(&new->cu_done);
         new->cu_msg.cm_vers = CLD_UPCALL_VERSION;
         put_unaligned(cn->cn_xid++, &new->cu_msg.cm_xid);
         new->cu_net = cn;