From: Ricardo Labiaga <Ricardo.Labiaga@xxxxxxxxxx>
nfs41_callback_up() initializes the necessary queues and creates the new
nfs41_callback_svc thread. This thread executes the callback service which
waits for requests to arrive on the svc_serv->sv_cb_list.
NFS41_BC_MIN_CALLBACKS is set to 1 because we expect callbacks to not
cause substantial latency.
The actual processing of the callback will be implemented as a separate patch.
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@xxxxxxxxxx>
Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
---
fs/nfs/callback.c | 76 +++++++++++++++++++++++++++++++++++++++++++-
fs/nfs/callback.h | 8 +++++
include/linux/sunrpc/svc.h | 2 +
3 files changed, 85 insertions(+), 1 deletions(-)
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 2f5acd3..86f4d88 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -16,6 +16,9 @@
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
+#if defined(CONFIG_NFS_V4_1)
+#include <linux/sunrpc/bc_xprt.h>
+#endif
#include <net/inet_sock.h>
@@ -126,6 +129,69 @@ nfs4_callback_up(struct svc_serv *serv)
return svc_prepare_thread(serv, &serv->sv_pools[0]);
}
+#if defined(CONFIG_NFS_V4_1)
+/*
+ * The callback service for NFSv4.1 callbacks
+ */
+static int
+nfs41_callback_svc(void *vrqstp)
+{
+ struct svc_rqst *rqstp = vrqstp;
+ struct svc_serv *serv = rqstp->rq_server;
+ struct rpc_rqst *req;
+ int error;
+ DEFINE_WAIT(wq);
+
+ set_freezable();
+
+ /*
+ * FIXME: do we really need to run this under the BKL? If so, please
+ * add a comment about what it's intended to protect.
+ */
+ lock_kernel();
+ while (!kthread_should_stop()) {
+ prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
+ spin_lock_bh(&serv->sv_cb_lock);
+ if (!list_empty(&serv->sv_cb_list)) {
+ req = list_first_entry(&serv->sv_cb_list,
+ struct rpc_rqst, rq_bc_list);
+ list_del(&req->rq_bc_list);
+ spin_unlock_bh(&serv->sv_cb_lock);
+ dprintk("Invoking bc_svc_process()\n");
+ error = bc_svc_process(serv, req, rqstp);
+ dprintk("bc_svc_process() returned w/ error code= %d\n",
+ error);
+ } else {
+ spin_unlock_bh(&serv->sv_cb_lock);
+ schedule();
+ }
+ finish_wait(&serv->sv_cb_waitq, &wq);
+ }
+ unlock_kernel();
+ nfs_callback_info.task = NULL;
+ svc_exit_thread(rqstp);
+ return 0;
+}
+
+/*
+ * Bring up the NFSv4.1 callback service
+ */
+struct svc_rqst *
+nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
+{
+ /*
+ * Save the svc_serv in the transport so that it can
+ * be referenced when the session backchannel is initialized
+ */
+ xprt->bc_serv = serv;
+
+ INIT_LIST_HEAD(&serv->sv_cb_list);
+ spin_lock_init(&serv->sv_cb_lock);
+ init_waitqueue_head(&serv->sv_cb_waitq);
+ return svc_prepare_thread(serv, &serv->sv_pools[0]);
+}
+#endif /* CONFIG_NFS_V4_1 */
+
/*
* Bring up the callback thread if it is not already up.
*/
@@ -136,6 +202,9 @@ int nfs_callback_up(u32 minorversion, void *args)
int (* callback_svc)(void *vrqstp);
char svc_name[12];
int ret = 0;
+#if defined(CONFIG_NFS_V4_1)
+ struct rpc_xprt *xprt = (struct rpc_xprt *)args;
+#endif /* CONFIG_NFS_V4_1 */
mutex_lock(&nfs_callback_mutex);
if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
@@ -153,7 +222,12 @@ int nfs_callback_up(u32 minorversion, void *args)
rqst = nfs4_callback_up(serv);
callback_svc = nfs4_callback_svc;
} else {
- BUG(); /* for now */
+#if defined(CONFIG_NFS_V4_1)
+ rqst = nfs41_callback_up(serv, xprt);
+ callback_svc = nfs41_callback_svc;
+#else /* CONFIG_NFS_V4_1 */
+ BUG();
+#endif /* CONFIG_NFS_V4_1 */
}
if (IS_ERR(rqst)) {
ret = PTR_ERR(rqst);
diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index a2b3ce4..49ea368 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -70,6 +70,14 @@ extern void nfs_callback_down(void);
#define nfs_callback_down() do {} while(0)
#endif
+#ifdef CONFIG_NFS_V4_1
+/*
+ * Callbacks are expected to not cause substantial latency,
+ * so we limit their concurrency to 1.
+ */
+#define NFS41_BC_MIN_CALLBACKS 1
+#endif /* CONFIG_NFS_V4_1 */
+
extern unsigned int nfs_callback_set_tcpport;
extern unsigned short nfs_callback_tcpport;
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 1d3b971..1bb51dc 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -403,6 +403,8 @@ struct svc_serv * svc_create_pooled(struct svc_program *, unsigned int,
int svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
void svc_destroy(struct svc_serv *);
int svc_process(struct svc_rqst *);
+int bc_svc_process(struct svc_serv *, struct rpc_rqst *,
+ struct svc_rqst *);
int svc_register(const struct svc_serv *, const unsigned short,
const unsigned short);
--
1.6.0.2
--
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