[PATCH 20/24] NFS: use a local RCU critical section in nfs_start_delegation_return

[Christoph Hellwig <hch@lst.de>]

Nested RCU critical sections are fine and very cheap.  Have a local one
in nfs_start_delegation_return so that the function is self-contained
and to prepare for simplifying the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/nfs/delegation.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 5d9dba7ab430..2ac897f67b01 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -309,11 +309,13 @@ nfs_start_delegation_return(struct nfs_inode *nfsi)
 	struct nfs_delegation *delegation;
 	bool return_now = false;
 
-	lockdep_assert_in_rcu_read_lock();
-
+	rcu_read_lock();
 	delegation = rcu_dereference(nfsi->delegation);
-	if (!delegation || !refcount_inc_not_zero(&delegation->refcount))
+	if (!delegation || !refcount_inc_not_zero(&delegation->refcount)) {
+		rcu_read_unlock();
 		return NULL;
+	}
+	rcu_read_unlock();
 
 	spin_lock(&delegation->lock);
 	if (delegation->inode &&
@@ -762,10 +764,7 @@ int nfs4_inode_return_delegation(struct inode *inode)
 	struct nfs_delegation *delegation;
 	int err;
 
-	rcu_read_lock();
 	delegation = nfs_start_delegation_return(nfsi);
-	rcu_read_unlock();
-
 	if (!delegation)
 		return 0;
 
-- 
2.47.3