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Subject[PATCH 4.9 048/199] nfsd: fix a warning in __cld_pipe_upcall()
Date
From: Scott Mayhew <smayhew@redhat.com>

[ 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>
---
fs/nfsd/nfs4recover.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 66eaeb1e8c2ce..dc9586feab317 100644
--- 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;
--
2.20.1


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