[PATCH v1 031/104] NFSd: Convert delegation counter to an atomic_long_t type

[Jeff Layton <jlayton@xxxxxxxxxxxxxxx>]

From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

We want to convert to an atomic type so that we don't need to lock
across the call to alloc_init_deleg(). Then convert to a long type
so that we match the size of 'max_delegations'.

Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
 fs/nfsd/nfs4state.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a6c94e8a6ad8..020bc981ccd3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -312,7 +312,7 @@ static struct file *find_any_file(struct nfs4_file *f)
 	return ret;
 }
 
-static int num_delegations;
+static atomic_long_t num_delegations;
 unsigned long max_delegations;
 
 /*
@@ -504,20 +504,22 @@ static struct nfs4_ol_stateid * nfs4_alloc_stateid(struct nfs4_client *clp)
 static void nfs4_free_deleg(struct nfs4_stid *stid)
 {
 	nfs4_free_stid(deleg_slab, stid);
-	num_delegations--;
+	atomic_long_dec(&num_delegations);
 }
 
 static struct nfs4_delegation *
 alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh)
 {
 	struct nfs4_delegation *dp;
+	long n;
 
 	dprintk("NFSD alloc_init_deleg\n");
-	if (num_delegations > max_delegations)
-		return NULL;
+	n = atomic_long_inc_return(&num_delegations);
+	if (n < 0 || n > max_delegations)
+		goto out_dec;
 	dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab));
 	if (dp == NULL)
-		return dp;
+		goto out_dec;
 
 	dp->dl_stid.sc_free = nfs4_free_deleg;
 	/*
@@ -526,7 +528,6 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
 	 * 0 anyway just for consistency and use 1:
 	 */
 	dp->dl_stid.sc_stateid.si_generation = 1;
-	num_delegations++;
 	INIT_LIST_HEAD(&dp->dl_perfile);
 	INIT_LIST_HEAD(&dp->dl_perclnt);
 	INIT_LIST_HEAD(&dp->dl_recall_lru);
@@ -534,6 +535,9 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
 	fh_copy_shallow(&dp->dl_fh, &current_fh->fh_handle);
 	nfsd4_init_callback(&dp->dl_recall);
 	return dp;
+out_dec:
+	atomic_long_dec(&num_delegations);
+	return NULL;
 }
 
 static void remove_stid_locked(struct nfs4_client *clp, struct nfs4_stid *s)
-- 
1.9.3

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