nfsd: fix a warning in __cld_pipe_upcall()

[ Upstream commit b493fd31c0b89d9453917e977002de58bebc3802 ]

__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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 66eaeb1e8c2ce75559d4b03c36ab7a16bda56af5..dc9586feab31791d30fbc362496cafb1203ff699 100644 (file)
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -661,7 +661,7 @@ 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;
 };
 
@@ -670,23 +670,18 @@ __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;
@@ -753,7 +748,7 @@ 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;
 }
 
@@ -768,7 +763,7 @@ 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 = {
@@ -899,7 +894,7 @@ 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;