[PATCH v3 02/11] NFS: callback service creation function introduced

Stanislav Kinsbursky
2012-07-03T16:23:37Z

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 nfs_callback_up().

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
---
fs/nfs/callback.c | 55 +++++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 2d3019d..f8d0c21 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -241,12 +241,46 @@ static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
}
#endif /* CONFIG_NFS_V4_1 */

+static struct svc_serv *nfs_callback_create_svc(int minorversion)
+{
+ struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
+ struct svc_serv *serv;
+
+ /*
+ * Check whether we're already up and running.
+ */
+ if (cb_info->task) {
+ /*
+ * Note: increase service usage, because later in case of error
+ * svc_destroy() will be called.
+ */
+ svc_get(cb_info->serv);
+ return cb_info->serv;
+ }
+
+ /*
+ * Sanity check: if there's no task,
+ * we should be the first user ...
+ */
+ if (cb_info->users)
+ printk(KERN_WARNING "nfs_callback_up: no kthread, %d users??\n",
+ cb_info->users);
+
+ serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
+ if (!serv) {
+ printk(KERN_ERR "lockd_up: create service failed\n");
+ return ERR_PTR(-ENOMEM);
+ }
+ dprintk("nfs_callback_up: service created\n");
+ return serv;
+}
+
/*
* Bring up the callback thread if it is not already up.
*/
int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
{
- struct svc_serv *serv = NULL;
+ struct svc_serv *serv;
struct svc_rqst *rqstp;
int (*callback_svc)(void *vrqstp);
struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
@@ -256,15 +290,17 @@ int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
struct net *net = &init_net;

mutex_lock(&nfs_callback_mutex);
+
+ serv = nfs_callback_create_svc(minorversion);
+ if (IS_ERR(serv)) {
+ ret = PTR_ERR(serv);
+ goto err_create;
+ }
+
if (cb_info->users++ || cb_info->task != NULL) {
nfs_callback_bc_serv(minorversion, xprt, cb_info);
goto out;
}
- serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
- if (!serv) {
- ret = -ENOMEM;
- goto out_err;
- }

ret = svc_bind(serv, net);
if (ret < 0) {
@@ -305,16 +341,15 @@ out:
* on both success and failure so that the refcount is 1 when the
* thread exits.
*/
- if (serv)
- svc_destroy(serv);
+ svc_destroy(serv);
+err_create:
mutex_unlock(&nfs_callback_mutex);
return ret;
out_err:
dprintk("NFS: Couldn't create callback socket or server thread; "
"err = %d\n", ret);
cb_info->users--;
- if (serv)
- svc_shutdown_net(serv, net);
+ svc_shutdown_net(serv, net);
goto out;
}