From: Jeff Layton <jlayton@primarydata.com>
Date: Tue, 8 Jul 2014 18:02:50 +0000 (-0400)
Subject: nfsd: reduce some spinlocking in put_client_renew
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=d6c249b4d4cfef894cbda224a7a063d17aacb60a;p=deliverable%2Flinux.git

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 63c142059137..3704789ca4b7 100644
--- 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);
 }