[PATCH 3/6] LockD: service creation function introduced

From: Stanislav Kinsbursky
Date: Wed Apr 25 2012 - 10:23:08 EST


This function creates service if it's not exist, or increase usage counter of
the existent, and returns pointer to it.
Usage counter will be droppepd by svc_destroy() later in lockd_up().

Signed-off-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>

---
fs/lockd/svc.c | 38 +++++++++++++++++++++++++++-----------
1 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 71c6c31..ad11ea7 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -291,21 +291,20 @@ static void lockd_down_net(struct svc_serv *serv, struct net *net)
}
}

-/*
- * Bring up the lockd process if it's not already up.
- */
-int lockd_up(struct net *net)
+static struct svc_serv *lockd_create_svc(void)
{
struct svc_serv *serv;
- int error = 0;

- mutex_lock(&nlmsvc_mutex);
/*
* Check whether we're already up and running.
*/
if (nlmsvc_rqst) {
- error = lockd_up_net(nlmsvc_rqst->rq_server, net);
- goto out;
+ /*
+ * Note: increase service usage, because later in case of error
+ * svc_destroy() will be called.
+ */
+ svc_get(nlmsvc_rqst->rq_server);
+ return nlmsvc_rqst->rq_server;
}

/*
@@ -316,11 +315,28 @@ int lockd_up(struct net *net)
printk(KERN_WARNING
"lockd_up: no pid, %d users??\n", nlmsvc_users);

- error = -ENOMEM;
serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
if (!serv) {
printk(KERN_WARNING "lockd_up: create service failed\n");
- goto out;
+ return ERR_PTR(-ENOMEM);
+ }
+ return serv;
+}
+
+/*
+ * Bring up the lockd process if it's not already up.
+ */
+int lockd_up(struct net *net)
+{
+ struct svc_serv *serv;
+ int error = 0;
+
+ mutex_lock(&nlmsvc_mutex);
+
+ serv = lockd_create_svc();
+ if (IS_ERR(serv)) {
+ error = PTR_ERR(serv);
+ goto err_create;
}

error = lockd_up_net(serv, net);
@@ -360,9 +376,9 @@ int lockd_up(struct net *net)
*/
err_net:
svc_destroy(serv);
-out:
if (!error)
nlmsvc_users++;
+err_create:
mutex_unlock(&nlmsvc_mutex);
return error;


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