nfsd: reduce some spinlocking in put_client_renew

No need to take the lock unless the count goes to 0.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 63c142059137e750cdd498ef7c66b40120cf2b7e..3704789ca4b7c3fe1db822e5c98ccf40bcca6802 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -193,8 +193,10 @@ static void put_client_renew(struct nfs4_client *clp)
 {
        struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
 
-       spin_lock(&nn->client_lock);
-       put_client_renew_locked(clp);
+       if (!atomic_dec_and_lock(&clp->cl_refcount, &nn->client_lock))
+               return;
+       if (!is_client_expired(clp))
+               renew_client_locked(clp);
        spin_unlock(&nn->client_lock);
 }