[PATCH v2 0/8] Clean up struct svc_serv_ops

[PATCH v2 0/8] Clean up struct svc_serv_ops

[Chuck Lever]

Here is the completed series of patches to remove struct
svc_serv_ops, as suggested by Neil Brown. The original material was
introduced several years ago when we planned to convert the RPC
server to use work queues. That work was never completed.

Removal now is to eliminate some unnecessary virtual functions
and to pave the way for the possibility of dynamic nfsd thread
management.

The full set of patches has been provisionally applied to my
for-next branch to enable broad testing. Comments welcome.

---

Chuck Lever (8):
      SUNRPC: Remove the .svo_enqueue_xprt method
      SUNRPC: Merge svc_do_enqueue_xprt() into svc_enqueue_xprt()
      SUNRPC: Remove svo_shutdown method
      SUNRPC: Rename svc_create_xprt()
      SUNRPC: Rename svc_close_xprt()
      SUNRPC: Remove svc_shutdown_net()
      NFSD: Remove svc_serv_ops::svo_module
      NFSD: Move svc_serv_ops::svo_function into struct svc_serv


 fs/lockd/svc.c                             | 24 +++-----
 fs/nfs/callback.c                          | 66 +++++++--------------
 fs/nfs/nfs4state.c                         |  1 -
 fs/nfsd/nfsctl.c                           | 10 ++--
 fs/nfsd/nfssvc.c                           | 23 +++-----
 include/linux/sunrpc/svc.h                 | 26 ++-------
 include/linux/sunrpc/svc_xprt.h            | 11 ++--
 kernel/module.c                            |  2 +-
 net/sunrpc/svc.c                           | 50 ++++++++--------
 net/sunrpc/svc_xprt.c                      | 68 ++++++++++++++--------
 net/sunrpc/xprtrdma/svc_rdma_backchannel.c |  2 +-
 11 files changed, 122 insertions(+), 161 deletions(-)

--
Chuck Lever

[PATCH v2 1/8] SUNRPC: Remove the .svo_enqueue_xprt method

[Chuck Lever]

We have never been able to track down and address the underlying
cause of the performance issues with workqueue-based service
support. svo_enqueue_xprt is called multiple times per RPC, so
it adds instruction path length, but always ends up at the same
function: svc_xprt_do_enqueue(). We do not anticipate needing
this flexibility for dynamic nfsd thread management support.

As a micro-optimization, remove .svo_enqueue_xprt because
Spectre/Meltdown makes virtual function calls more costly.

This change essentially reverts commit b9e13cdfac70 ("nfsd/sunrpc:
turn enqueueing a svc_xprt into a svc_serv operation").

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/lockd/svc.c                  |    1 -
 fs/nfs/callback.c               |    2 --
 fs/nfsd/nfssvc.c                |    1 -
 include/linux/sunrpc/svc.h      |    3 ---
 include/linux/sunrpc/svc_xprt.h |    1 -
 net/sunrpc/svc_xprt.c           |   10 +++++-----
 6 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 0475c5a5d061..3a05af873625 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -353,7 +353,6 @@ static struct notifier_block lockd_inet6addr_notifier = {
 static const struct svc_serv_ops lockd_sv_ops = {
 	.svo_shutdown		= svc_rpcb_cleanup,
 	.svo_function		= lockd,
-	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
 	.svo_module		= THIS_MODULE,
 };
 
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 054cc1255fac..7a810f885063 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -234,13 +234,11 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 
 static const struct svc_serv_ops nfs40_cb_sv_ops = {
 	.svo_function		= nfs4_callback_svc,
-	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
 	.svo_module		= THIS_MODULE,
 };
 #if defined(CONFIG_NFS_V4_1)
 static const struct svc_serv_ops nfs41_cb_sv_ops = {
 	.svo_function		= nfs41_callback_svc,
-	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
 	.svo_module		= THIS_MODULE,
 };
 
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index b8c682b62d29..aeeac6de1f0a 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -615,7 +615,6 @@ static int nfsd_get_default_max_blksize(void)
 static const struct svc_serv_ops nfsd_thread_sv_ops = {
 	.svo_shutdown		= nfsd_last_thread,
 	.svo_function		= nfsd,
-	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
 	.svo_module		= THIS_MODULE,
 };
 
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index f35c22b3355f..6ef9c1cafd0b 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -61,9 +61,6 @@ struct svc_serv_ops {
 	/* function for service threads to run */
 	int		(*svo_function)(void *);
 
-	/* queue up a transport for servicing */
-	void		(*svo_enqueue_xprt)(struct svc_xprt *);
-
 	/* optional module to count when adding threads.
 	 * Thread function must call module_put_and_kthread_exit() to exit.
 	 */
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 571f605bc91e..a3ba027fb4ba 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -131,7 +131,6 @@ int	svc_create_xprt(struct svc_serv *, const char *, struct net *,
 			const int, const unsigned short, int,
 			const struct cred *);
 void	svc_xprt_received(struct svc_xprt *xprt);
-void	svc_xprt_do_enqueue(struct svc_xprt *xprt);
 void	svc_xprt_enqueue(struct svc_xprt *xprt);
 void	svc_xprt_put(struct svc_xprt *xprt);
 void	svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt);
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index b21ad7994147..9fce4f7774bb 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -32,6 +32,7 @@ static int svc_deferred_recv(struct svc_rqst *rqstp);
 static struct cache_deferred_req *svc_defer(struct cache_req *req);
 static void svc_age_temp_xprts(struct timer_list *t);
 static void svc_delete_xprt(struct svc_xprt *xprt);
+static void svc_xprt_do_enqueue(struct svc_xprt *xprt);
 
 /* apparently the "standard" is that clients close
  * idle connections after 5 minutes, servers after
@@ -266,12 +267,12 @@ void svc_xprt_received(struct svc_xprt *xprt)
 	}
 
 	/* As soon as we clear busy, the xprt could be closed and
-	 * 'put', so we need a reference to call svc_enqueue_xprt with:
+	 * 'put', so we need a reference to call svc_xprt_do_enqueue with:
 	 */
 	svc_xprt_get(xprt);
 	smp_mb__before_atomic();
 	clear_bit(XPT_BUSY, &xprt->xpt_flags);
-	xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
+	svc_xprt_do_enqueue(xprt);
 	svc_xprt_put(xprt);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_received);
@@ -423,7 +424,7 @@ static bool svc_xprt_ready(struct svc_xprt *xprt)
 	return false;
 }
 
-void svc_xprt_do_enqueue(struct svc_xprt *xprt)
+static void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 {
 	struct svc_pool *pool;
 	struct svc_rqst	*rqstp = NULL;
@@ -467,7 +468,6 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 	put_cpu();
 	trace_svc_xprt_enqueue(xprt, rqstp);
 }
-EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
 
 /*
  * Queue up a transport with data pending. If there are idle nfsd
@@ -478,7 +478,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
 {
 	if (test_bit(XPT_BUSY, &xprt->xpt_flags))
 		return;
-	xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
+	svc_xprt_do_enqueue(xprt);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
 

[PATCH v2 2/8] SUNRPC: Merge svc_do_enqueue_xprt() into svc_enqueue_xprt()

[Chuck Lever]

Neil says:
"These functions were separated in commit 0971374e2818 ("SUNRPC:
Reduce contention in svc_xprt_enqueue()") so that the XPT_BUSY check
happened before taking any spinlocks.

We have since moved or removed the spinlocks so the extra test is
fairly pointless."

I've made this a separate patch in case the XPT_BUSY change has
unexpected consequences and needs to be reverted.

Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/svc_xprt.c |   26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 9fce4f7774bb..1c2295209d08 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -32,7 +32,6 @@ static int svc_deferred_recv(struct svc_rqst *rqstp);
 static struct cache_deferred_req *svc_defer(struct cache_req *req);
 static void svc_age_temp_xprts(struct timer_list *t);
 static void svc_delete_xprt(struct svc_xprt *xprt);
-static void svc_xprt_do_enqueue(struct svc_xprt *xprt);
 
 /* apparently the "standard" is that clients close
  * idle connections after 5 minutes, servers after
@@ -267,12 +266,12 @@ void svc_xprt_received(struct svc_xprt *xprt)
 	}
 
 	/* As soon as we clear busy, the xprt could be closed and
-	 * 'put', so we need a reference to call svc_xprt_do_enqueue with:
+	 * 'put', so we need a reference to call svc_xprt_enqueue with:
 	 */
 	svc_xprt_get(xprt);
 	smp_mb__before_atomic();
 	clear_bit(XPT_BUSY, &xprt->xpt_flags);
-	svc_xprt_do_enqueue(xprt);
+	svc_xprt_enqueue(xprt);
 	svc_xprt_put(xprt);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_received);
@@ -412,6 +411,8 @@ static bool svc_xprt_ready(struct svc_xprt *xprt)
 	smp_rmb();
 	xpt_flags = READ_ONCE(xprt->xpt_flags);
 
+	if (xpt_flags & BIT(XPT_BUSY))
+		return false;
 	if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
 		return true;
 	if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
@@ -424,7 +425,12 @@ static bool svc_xprt_ready(struct svc_xprt *xprt)
 	return false;
 }
 
-static void svc_xprt_do_enqueue(struct svc_xprt *xprt)
+/**
+ * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
+ * @xprt: transport with data pending
+ *
+ */
+void svc_xprt_enqueue(struct svc_xprt *xprt)
 {
 	struct svc_pool *pool;
 	struct svc_rqst	*rqstp = NULL;
@@ -468,18 +474,6 @@ static void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 	put_cpu();
 	trace_svc_xprt_enqueue(xprt, rqstp);
 }
-
-/*
- * Queue up a transport with data pending. If there are idle nfsd
- * processes, wake 'em up.
- *
- */
-void svc_xprt_enqueue(struct svc_xprt *xprt)
-{
-	if (test_bit(XPT_BUSY, &xprt->xpt_flags))
-		return;
-	svc_xprt_do_enqueue(xprt);
-}
 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
 
 /*

[PATCH v2 3/8] SUNRPC: Remove svo_shutdown method

[Chuck Lever]

Clean up. Neil observed that "any code that calls svc_shutdown_net()
knows what the shutdown function should be, and so can call it
directly."

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: NeilBrown <neilb@suse.de>
---
 fs/lockd/svc.c             |    5 ++---
 fs/nfsd/nfssvc.c           |    2 +-
 include/linux/sunrpc/svc.h |    3 ---
 net/sunrpc/svc.c           |    3 ---
 4 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 3a05af873625..f5b688a844aa 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -249,6 +249,7 @@ static int make_socks(struct svc_serv *serv, struct net *net,
 		printk(KERN_WARNING
 			"lockd_up: makesock failed, error=%d\n", err);
 	svc_shutdown_net(serv, net);
+	svc_rpcb_cleanup(serv, net);
 	return err;
 }
 
@@ -287,8 +288,7 @@ static void lockd_down_net(struct svc_serv *serv, struct net *net)
 			cancel_delayed_work_sync(&ln->grace_period_end);
 			locks_end_grace(&ln->lockd_manager);
 			svc_shutdown_net(serv, net);
-			dprintk("%s: per-net data destroyed; net=%x\n",
-				__func__, net->ns.inum);
+			svc_rpcb_cleanup(serv, net);
 		}
 	} else {
 		pr_err("%s: no users! net=%x\n",
@@ -351,7 +351,6 @@ static struct notifier_block lockd_inet6addr_notifier = {
 #endif
 
 static const struct svc_serv_ops lockd_sv_ops = {
-	.svo_shutdown		= svc_rpcb_cleanup,
 	.svo_function		= lockd,
 	.svo_module		= THIS_MODULE,
 };
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index aeeac6de1f0a..0c6b216e439e 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -613,7 +613,6 @@ static int nfsd_get_default_max_blksize(void)
 }
 
 static const struct svc_serv_ops nfsd_thread_sv_ops = {
-	.svo_shutdown		= nfsd_last_thread,
 	.svo_function		= nfsd,
 	.svo_module		= THIS_MODULE,
 };
@@ -724,6 +723,7 @@ void nfsd_put(struct net *net)
 
 	if (kref_put(&nn->nfsd_serv->sv_refcnt, nfsd_noop)) {
 		svc_shutdown_net(nn->nfsd_serv, net);
+		nfsd_last_thread(nn->nfsd_serv, net);
 		svc_destroy(&nn->nfsd_serv->sv_refcnt);
 		spin_lock(&nfsd_notifier_lock);
 		nn->nfsd_serv = NULL;
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 6ef9c1cafd0b..63794d772eb3 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -55,9 +55,6 @@ struct svc_pool {
 struct svc_serv;
 
 struct svc_serv_ops {
-	/* Callback to use when last thread exits. */
-	void		(*svo_shutdown)(struct svc_serv *, struct net *);
-
 	/* function for service threads to run */
 	int		(*svo_function)(void *);
 
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 2aabec2b4bec..74a75a22da9a 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -539,9 +539,6 @@ EXPORT_SYMBOL_GPL(svc_create_pooled);
 void svc_shutdown_net(struct svc_serv *serv, struct net *net)
 {
 	svc_close_net(serv, net);
-
-	if (serv->sv_ops->svo_shutdown)
-		serv->sv_ops->svo_shutdown(serv, net);
 }
 EXPORT_SYMBOL_GPL(svc_shutdown_net);
 

[PATCH v2 4/8] SUNRPC: Rename svc_create_xprt()

[Chuck Lever]

Clean up: Use the "svc_xprt_<task>" function naming convention as
is used for other external APIs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/lockd/svc.c                  |    4 ++--
 fs/nfs/callback.c               |   12 ++++++------
 fs/nfsd/nfsctl.c                |    8 ++++----
 fs/nfsd/nfssvc.c                |    8 ++++----
 include/linux/sunrpc/svc_xprt.h |    7 ++++---
 net/sunrpc/svc_xprt.c           |   24 +++++++++++++++++++-----
 6 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index f5b688a844aa..bba6f2b45b64 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -197,8 +197,8 @@ static int create_lockd_listener(struct svc_serv *serv, const char *name,
 
 	xprt = svc_find_xprt(serv, name, net, family, 0);
 	if (xprt == NULL)
-		return svc_create_xprt(serv, name, net, family, port,
-						SVC_SOCK_DEFAULTS, cred);
+		return svc_xprt_create(serv, name, net, family, port,
+				       SVC_SOCK_DEFAULTS, cred);
 	svc_xprt_put(xprt);
 	return 0;
 }
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 7a810f885063..c1a8767100ae 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -45,18 +45,18 @@ static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
 	int ret;
 	struct nfs_net *nn = net_generic(net, nfs_net_id);
 
-	ret = svc_create_xprt(serv, "tcp", net, PF_INET,
-				nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
-				cred);
+	ret = svc_xprt_create(serv, "tcp", net, PF_INET,
+			      nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
+			      cred);
 	if (ret <= 0)
 		goto out_err;
 	nn->nfs_callback_tcpport = ret;
 	dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
 		nn->nfs_callback_tcpport, PF_INET, net->ns.inum);
 
-	ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
-				nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
-				cred);
+	ret = svc_xprt_create(serv, "tcp", net, PF_INET6,
+			      nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
+			      cred);
 	if (ret > 0) {
 		nn->nfs_callback_tcpport6 = ret;
 		dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 68b020f2002b..8fec779994f7 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -772,13 +772,13 @@ static ssize_t __write_ports_addxprt(char *buf, struct net *net, const struct cr
 	if (err != 0)
 		return err;
 
-	err = svc_create_xprt(nn->nfsd_serv, transport, net,
-				PF_INET, port, SVC_SOCK_ANONYMOUS, cred);
+	err = svc_xprt_create(nn->nfsd_serv, transport, net,
+			      PF_INET, port, SVC_SOCK_ANONYMOUS, cred);
 	if (err < 0)
 		goto out_err;
 
-	err = svc_create_xprt(nn->nfsd_serv, transport, net,
-				PF_INET6, port, SVC_SOCK_ANONYMOUS, cred);
+	err = svc_xprt_create(nn->nfsd_serv, transport, net,
+			      PF_INET6, port, SVC_SOCK_ANONYMOUS, cred);
 	if (err < 0 && err != -EAFNOSUPPORT)
 		goto out_close;
 
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 0c6b216e439e..ae25b7b3af99 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -293,13 +293,13 @@ static int nfsd_init_socks(struct net *net, const struct cred *cred)
 	if (!list_empty(&nn->nfsd_serv->sv_permsocks))
 		return 0;
 
-	error = svc_create_xprt(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
-					SVC_SOCK_DEFAULTS, cred);
+	error = svc_xprt_create(nn->nfsd_serv, "udp", net, PF_INET, NFS_PORT,
+				SVC_SOCK_DEFAULTS, cred);
 	if (error < 0)
 		return error;
 
-	error = svc_create_xprt(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
-					SVC_SOCK_DEFAULTS, cred);
+	error = svc_xprt_create(nn->nfsd_serv, "tcp", net, PF_INET, NFS_PORT,
+				SVC_SOCK_DEFAULTS, cred);
 	if (error < 0)
 		return error;
 
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index a3ba027fb4ba..a7f6f17c3dc5 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -127,9 +127,10 @@ int	svc_reg_xprt_class(struct svc_xprt_class *);
 void	svc_unreg_xprt_class(struct svc_xprt_class *);
 void	svc_xprt_init(struct net *, struct svc_xprt_class *, struct svc_xprt *,
 		      struct svc_serv *);
-int	svc_create_xprt(struct svc_serv *, const char *, struct net *,
-			const int, const unsigned short, int,
-			const struct cred *);
+int	svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
+			struct net *net, const int family,
+			const unsigned short port, int flags,
+			const struct cred *cred);
 void	svc_xprt_received(struct svc_xprt *xprt);
 void	svc_xprt_enqueue(struct svc_xprt *xprt);
 void	svc_xprt_put(struct svc_xprt *xprt);
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 1c2295209d08..44be7193cd9b 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -285,7 +285,7 @@ void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
 	svc_xprt_received(new);
 }
 
-static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
+static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
 			    struct net *net, const int family,
 			    const unsigned short port, int flags,
 			    const struct cred *cred)
@@ -321,21 +321,35 @@ static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 	return -EPROTONOSUPPORT;
 }
 
-int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
+/**
+ * svc_xprt_create - Add a new listener to @serv
+ * @serv: target RPC service
+ * @xprt_name: transport class name
+ * @net: network namespace
+ * @family: network address family
+ * @port: listener port
+ * @flags: SVC_SOCK flags
+ * @cred: credential to bind to this transport
+ *
+ * Return values:
+ *   %0: New listener added successfully
+ *   %-EPROTONOSUPPORT: Requested transport type not supported
+ */
+int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
 		    struct net *net, const int family,
 		    const unsigned short port, int flags,
 		    const struct cred *cred)
 {
 	int err;
 
-	err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
+	err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
 	if (err == -EPROTONOSUPPORT) {
 		request_module("svc%s", xprt_name);
-		err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
+		err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
 	}
 	return err;
 }
-EXPORT_SYMBOL_GPL(svc_create_xprt);
+EXPORT_SYMBOL_GPL(svc_xprt_create);
 
 /*
  * Copy the local and remote xprt addresses to the rqstp structure

[PATCH v2 5/8] SUNRPC: Rename svc_close_xprt()

[Chuck Lever]

Clean up: Use the "svc_xprt_<task>" function naming convention as
is used for other external APIs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfsctl.c                           |    2 +-
 include/linux/sunrpc/svc_xprt.h            |    2 +-
 net/sunrpc/svc.c                           |    2 +-
 net/sunrpc/svc_xprt.c                      |    9 +++++++--
 net/sunrpc/xprtrdma/svc_rdma_backchannel.c |    2 +-
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 8fec779994f7..16920e4512bd 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -790,7 +790,7 @@ static ssize_t __write_ports_addxprt(char *buf, struct net *net, const struct cr
 out_close:
 	xprt = svc_find_xprt(nn->nfsd_serv, transport, net, PF_INET, port);
 	if (xprt != NULL) {
-		svc_close_xprt(xprt);
+		svc_xprt_close(xprt);
 		svc_xprt_put(xprt);
 	}
 out_err:
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index a7f6f17c3dc5..bf7d029fb48c 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -135,7 +135,7 @@ void	svc_xprt_received(struct svc_xprt *xprt);
 void	svc_xprt_enqueue(struct svc_xprt *xprt);
 void	svc_xprt_put(struct svc_xprt *xprt);
 void	svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt);
-void	svc_close_xprt(struct svc_xprt *xprt);
+void	svc_xprt_close(struct svc_xprt *xprt);
 int	svc_port_is_privileged(struct sockaddr *sin);
 int	svc_print_xprts(char *buf, int maxlen);
 struct	svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 74a75a22da9a..53efef3db3a9 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1352,7 +1352,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 	svc_authorise(rqstp);
 close_xprt:
 	if (rqstp->rq_xprt && test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
-		svc_close_xprt(rqstp->rq_xprt);
+		svc_xprt_close(rqstp->rq_xprt);
 	dprintk("svc: svc_process close\n");
 	return 0;
 
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 44be7193cd9b..6809116c996a 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -1068,7 +1068,12 @@ static void svc_delete_xprt(struct svc_xprt *xprt)
 	svc_xprt_put(xprt);
 }
 
-void svc_close_xprt(struct svc_xprt *xprt)
+/**
+ * svc_xprt_close - Close a client connection
+ * @xprt: transport to disconnect
+ *
+ */
+void svc_xprt_close(struct svc_xprt *xprt)
 {
 	trace_svc_xprt_close(xprt);
 	set_bit(XPT_CLOSE, &xprt->xpt_flags);
@@ -1083,7 +1088,7 @@ void svc_close_xprt(struct svc_xprt *xprt)
 	 */
 	svc_delete_xprt(xprt);
 }
-EXPORT_SYMBOL_GPL(svc_close_xprt);
+EXPORT_SYMBOL_GPL(svc_xprt_close);
 
 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
 {
diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
index 16897fcb659c..85c8cdda98b1 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
@@ -198,7 +198,7 @@ static int xprt_rdma_bc_send_request(struct rpc_rqst *rqst)
 
 	ret = rpcrdma_bc_send_request(rdma, rqst);
 	if (ret == -ENOTCONN)
-		svc_close_xprt(sxprt);
+		svc_xprt_close(sxprt);
 	return ret;
 }
 

[PATCH v2 6/8] SUNRPC: Remove svc_shutdown_net()

[Chuck Lever]

Clean up: svc_shutdown_net() now does nothing but call
svc_close_net(). Replace all external call sites.

svc_close_net() is renamed to be the inverse of svc_xprt_create().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/lockd/svc.c                  |    4 ++--
 fs/nfs/callback.c               |    2 +-
 fs/nfsd/nfssvc.c                |    2 +-
 include/linux/sunrpc/svc.h      |    1 -
 include/linux/sunrpc/svc_xprt.h |    1 +
 net/sunrpc/svc.c                |    6 ------
 net/sunrpc/svc_xprt.c           |    9 +++++++--
 7 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index bba6f2b45b64..c83ec4a375bc 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -248,7 +248,7 @@ static int make_socks(struct svc_serv *serv, struct net *net,
 	if (warned++ == 0)
 		printk(KERN_WARNING
 			"lockd_up: makesock failed, error=%d\n", err);
-	svc_shutdown_net(serv, net);
+	svc_xprt_destroy_all(serv, net);
 	svc_rpcb_cleanup(serv, net);
 	return err;
 }
@@ -287,7 +287,7 @@ static void lockd_down_net(struct svc_serv *serv, struct net *net)
 			nlm_shutdown_hosts_net(net);
 			cancel_delayed_work_sync(&ln->grace_period_end);
 			locks_end_grace(&ln->lockd_manager);
-			svc_shutdown_net(serv, net);
+			svc_xprt_destroy_all(serv, net);
 			svc_rpcb_cleanup(serv, net);
 		}
 	} else {
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index c1a8767100ae..c98c68513590 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -189,7 +189,7 @@ static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struc
 		return;
 
 	dprintk("NFS: destroy per-net callback data; net=%x\n", net->ns.inum);
-	svc_shutdown_net(serv, net);
+	svc_xprt_destroy_all(serv, net);
 }
 
 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index ae25b7b3af99..b92d272f4ba6 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -722,7 +722,7 @@ void nfsd_put(struct net *net)
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
 	if (kref_put(&nn->nfsd_serv->sv_refcnt, nfsd_noop)) {
-		svc_shutdown_net(nn->nfsd_serv, net);
+		svc_xprt_destroy_all(nn->nfsd_serv, net);
 		nfsd_last_thread(nn->nfsd_serv, net);
 		svc_destroy(&nn->nfsd_serv->sv_refcnt);
 		spin_lock(&nfsd_notifier_lock);
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 63794d772eb3..5603158b2aa7 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -508,7 +508,6 @@ struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
 			const struct svc_serv_ops *);
 int		   svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
 int		   svc_pool_stats_open(struct svc_serv *serv, struct file *file);
-void		   svc_shutdown_net(struct svc_serv *, struct net *);
 int		   svc_process(struct svc_rqst *);
 int		   bc_svc_process(struct svc_serv *, struct rpc_rqst *,
 			struct svc_rqst *);
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index bf7d029fb48c..42e113742429 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -131,6 +131,7 @@ int	svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
 			struct net *net, const int family,
 			const unsigned short port, int flags,
 			const struct cred *cred);
+void	svc_xprt_destroy_all(struct svc_serv *serv, struct net *net);
 void	svc_xprt_received(struct svc_xprt *xprt);
 void	svc_xprt_enqueue(struct svc_xprt *xprt);
 void	svc_xprt_put(struct svc_xprt *xprt);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 53efef3db3a9..08d684746452 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -536,12 +536,6 @@ svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
 }
 EXPORT_SYMBOL_GPL(svc_create_pooled);
 
-void svc_shutdown_net(struct svc_serv *serv, struct net *net)
-{
-	svc_close_net(serv, net);
-}
-EXPORT_SYMBOL_GPL(svc_shutdown_net);
-
 /*
  * Destroy an RPC service. Should be called with appropriate locking to
  * protect sv_permsocks and sv_tempsocks.
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 6809116c996a..0c117d3bfda8 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -1140,7 +1140,11 @@ static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
 	}
 }
 
-/*
+/**
+ * svc_xprt_destroy_all - Destroy transports associated with @serv
+ * @serv: RPC service to be shut down
+ * @net: target network namespace
+ *
  * Server threads may still be running (especially in the case where the
  * service is still running in other network namespaces).
  *
@@ -1152,7 +1156,7 @@ static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
  * threads, we may need to wait a little while and then check again to
  * see if they're done.
  */
-void svc_close_net(struct svc_serv *serv, struct net *net)
+void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
 {
 	int delay = 0;
 
@@ -1163,6 +1167,7 @@ void svc_close_net(struct svc_serv *serv, struct net *net)
 		msleep(delay++);
 	}
 }
+EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
 
 /*
  * Handle defer and revisit of requests

[PATCH v2 7/8] NFSD: Remove svc_serv_ops::svo_module

[Chuck Lever]

struct svc_serv_ops is about to be removed.

Neil Brown says:
> I suspect svo_module can go as well - I don't think the thread is
> ever the thing that primarily keeps a module active.

A random sample of kthread_create() callers shows sunrpc is the only
one that manages module reference count in this way.

Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/lockd/svc.c             |    4 +---
 fs/nfs/callback.c          |    7 ++-----
 fs/nfs/nfs4state.c         |    1 -
 fs/nfsd/nfssvc.c           |    3 ---
 include/linux/sunrpc/svc.h |    5 -----
 kernel/module.c            |    2 +-
 net/sunrpc/svc.c           |    2 --
 7 files changed, 4 insertions(+), 20 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index c83ec4a375bc..bfde31124f3a 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -184,8 +184,7 @@ lockd(void *vrqstp)
 	dprintk("lockd_down: service stopped\n");
 
 	svc_exit_thread(rqstp);
-
-	module_put_and_kthread_exit(0);
+	return 0;
 }
 
 static int create_lockd_listener(struct svc_serv *serv, const char *name,
@@ -352,7 +351,6 @@ static struct notifier_block lockd_inet6addr_notifier = {
 
 static const struct svc_serv_ops lockd_sv_ops = {
 	.svo_function		= lockd,
-	.svo_module		= THIS_MODULE,
 };
 
 static int lockd_get(void)
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index c98c68513590..a494f9e7bd0a 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -17,7 +17,6 @@
 #include <linux/errno.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
-#include <linux/kthread.h>
 #include <linux/sunrpc/svcauth_gss.h>
 #include <linux/sunrpc/bc_xprt.h>
 
@@ -92,8 +91,8 @@ nfs4_callback_svc(void *vrqstp)
 			continue;
 		svc_process(rqstp);
 	}
+
 	svc_exit_thread(rqstp);
-	module_put_and_kthread_exit(0);
 	return 0;
 }
 
@@ -136,8 +135,8 @@ nfs41_callback_svc(void *vrqstp)
 			finish_wait(&serv->sv_cb_waitq, &wq);
 		}
 	}
+
 	svc_exit_thread(rqstp);
-	module_put_and_kthread_exit(0);
 	return 0;
 }
 
@@ -234,12 +233,10 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 
 static const struct svc_serv_ops nfs40_cb_sv_ops = {
 	.svo_function		= nfs4_callback_svc,
-	.svo_module		= THIS_MODULE,
 };
 #if defined(CONFIG_NFS_V4_1)
 static const struct svc_serv_ops nfs41_cb_sv_ops = {
 	.svo_function		= nfs41_callback_svc,
-	.svo_module		= THIS_MODULE,
 };
 
 static const struct svc_serv_ops *nfs4_cb_sv_ops[] = {
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index f5a62c0d999b..02a899e4390f 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -2697,6 +2697,5 @@ static int nfs4_run_state_manager(void *ptr)
 	allow_signal(SIGKILL);
 	nfs4_state_manager(clp);
 	nfs_put_client(clp);
-	module_put_and_kthread_exit(0);
 	return 0;
 }
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index b92d272f4ba6..544187a8a22b 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -614,7 +614,6 @@ static int nfsd_get_default_max_blksize(void)
 
 static const struct svc_serv_ops nfsd_thread_sv_ops = {
 	.svo_function		= nfsd,
-	.svo_module		= THIS_MODULE,
 };
 
 void nfsd_shutdown_threads(struct net *net)
@@ -1018,8 +1017,6 @@ nfsd(void *vrqstp)
 		msleep(20);
 	}
 
-	/* Release module */
-	module_put_and_kthread_exit(0);
 	return 0;
 }
 
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 5603158b2aa7..dfc9283f412f 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -57,11 +57,6 @@ struct svc_serv;
 struct svc_serv_ops {
 	/* function for service threads to run */
 	int		(*svo_function)(void *);
-
-	/* optional module to count when adding threads.
-	 * Thread function must call module_put_and_kthread_exit() to exit.
-	 */
-	struct module	*svo_module;
 };
 
 /*
diff --git a/kernel/module.c b/kernel/module.c
index 46a5c2ed1928..6cea788fd965 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -335,7 +335,7 @@ static inline void add_taint_module(struct module *mod, unsigned flag,
 
 /*
  * A thread that wants to hold a reference to a module only while it
- * is running can call this to safely exit.  nfsd and lockd use this.
+ * is running can call this to safely exit.
  */
 void __noreturn __module_put_and_kthread_exit(struct module *mod, long code)
 {
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 08d684746452..a90d555aa163 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -736,11 +736,9 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 		if (IS_ERR(rqstp))
 			return PTR_ERR(rqstp);
 
-		__module_get(serv->sv_ops->svo_module);
 		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
 					      node, "%s", serv->sv_name);
 		if (IS_ERR(task)) {
-			module_put(serv->sv_ops->svo_module);
 			svc_exit_thread(rqstp);
 			return PTR_ERR(task);
 		}

[PATCH v2 8/8] NFSD: Move svc_serv_ops::svo_function into struct svc_serv

[Chuck Lever]

Hoist svo_function back into svc_serv and remove struct
svc_serv_ops, since the struct is now devoid of fields.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/lockd/svc.c             |    6 +-----
 fs/nfs/callback.c          |   43 +++++++++++--------------------------------
 fs/nfsd/nfssvc.c           |    7 +------
 include/linux/sunrpc/svc.h |   14 ++++----------
 net/sunrpc/svc.c           |   37 ++++++++++++++++++++++++++-----------
 5 files changed, 43 insertions(+), 64 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index bfde31124f3a..59ef8a1f843f 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -349,10 +349,6 @@ static struct notifier_block lockd_inet6addr_notifier = {
 };
 #endif
 
-static const struct svc_serv_ops lockd_sv_ops = {
-	.svo_function		= lockd,
-};
-
 static int lockd_get(void)
 {
 	struct svc_serv *serv;
@@ -376,7 +372,7 @@ static int lockd_get(void)
 		nlm_timeout = LOCKD_DFLT_TIMEO;
 	nlmsvc_timeout = nlm_timeout * HZ;
 
-	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, &lockd_sv_ops);
+	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, lockd);
 	if (!serv) {
 		printk(KERN_WARNING "lockd_up: create service failed\n");
 		return -ENOMEM;
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index a494f9e7bd0a..456af7d230cf 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -231,29 +231,10 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 	return ret;
 }
 
-static const struct svc_serv_ops nfs40_cb_sv_ops = {
-	.svo_function		= nfs4_callback_svc,
-};
-#if defined(CONFIG_NFS_V4_1)
-static const struct svc_serv_ops nfs41_cb_sv_ops = {
-	.svo_function		= nfs41_callback_svc,
-};
-
-static const struct svc_serv_ops *nfs4_cb_sv_ops[] = {
-	[0] = &nfs40_cb_sv_ops,
-	[1] = &nfs41_cb_sv_ops,
-};
-#else
-static const struct svc_serv_ops *nfs4_cb_sv_ops[] = {
-	[0] = &nfs40_cb_sv_ops,
-	[1] = NULL,
-};
-#endif
-
 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 {
 	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
-	const struct svc_serv_ops *sv_ops;
+	int (*threadfn)(void *data);
 	struct svc_serv *serv;
 
 	/*
@@ -262,17 +243,6 @@ static struct svc_serv *nfs_callback_create_svc(int minorversion)
 	if (cb_info->serv)
 		return svc_get(cb_info->serv);
 
-	switch (minorversion) {
-	case 0:
-		sv_ops = nfs4_cb_sv_ops[0];
-		break;
-	default:
-		sv_ops = nfs4_cb_sv_ops[1];
-	}
-
-	if (sv_ops == NULL)
-		return ERR_PTR(-ENOTSUPP);
-
 	/*
 	 * Sanity check: if there's no task,
 	 * we should be the first user ...
@@ -281,7 +251,16 @@ static struct svc_serv *nfs_callback_create_svc(int minorversion)
 		printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 			cb_info->users);
 
-	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops);
+	threadfn = nfs4_callback_svc;
+#if defined(CONFIG_NFS_V4_1)
+	if (minorversion)
+		threadfn = nfs41_callback_svc;
+#else
+	if (minorversion)
+		return ERR_PTR(-ENOTSUPP);
+#endif
+	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
+			  threadfn);
 	if (!serv) {
 		printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 		return ERR_PTR(-ENOMEM);
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 544187a8a22b..5abbe5d1c77f 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -612,10 +612,6 @@ static int nfsd_get_default_max_blksize(void)
 	return ret;
 }
 
-static const struct svc_serv_ops nfsd_thread_sv_ops = {
-	.svo_function		= nfsd,
-};
-
 void nfsd_shutdown_threads(struct net *net)
 {
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
@@ -654,8 +650,7 @@ int nfsd_create_serv(struct net *net)
 	if (nfsd_max_blksize == 0)
 		nfsd_max_blksize = nfsd_get_default_max_blksize();
 	nfsd_reset_versions(nn);
-	serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
-				 &nfsd_thread_sv_ops);
+	serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, nfsd);
 	if (serv == NULL)
 		return -ENOMEM;
 
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index dfc9283f412f..a5dda4987e8b 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -52,13 +52,6 @@ struct svc_pool {
 	unsigned long		sp_flags;
 } ____cacheline_aligned_in_smp;
 
-struct svc_serv;
-
-struct svc_serv_ops {
-	/* function for service threads to run */
-	int		(*svo_function)(void *);
-};
-
 /*
  * RPC service.
  *
@@ -91,7 +84,8 @@ struct svc_serv {
 
 	unsigned int		sv_nrpools;	/* number of thread pools */
 	struct svc_pool *	sv_pools;	/* array of thread pools */
-	const struct svc_serv_ops *sv_ops;	/* server operations */
+	int			(*sv_threadfn)(void *data);
+
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 	struct list_head	sv_cb_list;	/* queue for callback requests
 						 * that arrive over the same
@@ -492,7 +486,7 @@ int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
 int svc_bind(struct svc_serv *serv, struct net *net);
 struct svc_serv *svc_create(struct svc_program *, unsigned int,
-			    const struct svc_serv_ops *);
+			    int (*threadfn)(void *data));
 struct svc_rqst *svc_rqst_alloc(struct svc_serv *serv,
 					struct svc_pool *pool, int node);
 void		   svc_rqst_replace_page(struct svc_rqst *rqstp,
@@ -500,7 +494,7 @@ void		   svc_rqst_replace_page(struct svc_rqst *rqstp,
 void		   svc_rqst_free(struct svc_rqst *);
 void		   svc_exit_thread(struct svc_rqst *);
 struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
-			const struct svc_serv_ops *);
+				     int (*threadfn)(void *data));
 int		   svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
 int		   svc_pool_stats_open(struct svc_serv *serv, struct file *file);
 int		   svc_process(struct svc_rqst *);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index a90d555aa163..557004017548 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -448,7 +448,7 @@ __svc_init_bc(struct svc_serv *serv)
  */
 static struct svc_serv *
 __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
-	     const struct svc_serv_ops *ops)
+	     int (*threadfn)(void *data))
 {
 	struct svc_serv	*serv;
 	unsigned int vers;
@@ -465,7 +465,7 @@ __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
 		bufsize = RPCSVC_MAXPAYLOAD;
 	serv->sv_max_payload = bufsize? bufsize : 4096;
 	serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
-	serv->sv_ops = ops;
+	serv->sv_threadfn = threadfn;
 	xdrsize = 0;
 	while (prog) {
 		prog->pg_lovers = prog->pg_nvers-1;
@@ -511,22 +511,37 @@ __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
 	return serv;
 }
 
-struct svc_serv *
-svc_create(struct svc_program *prog, unsigned int bufsize,
-	   const struct svc_serv_ops *ops)
+/**
+ * svc_create - Create an RPC service
+ * @prog: the RPC program the new service will handle
+ * @bufsize: maximum message size for @prog
+ * @threadfn: a function to service RPC requests for @prog
+ *
+ * Returns an instantiated struct svc_serv object or NULL.
+ */
+struct svc_serv *svc_create(struct svc_program *prog, unsigned int bufsize,
+			    int (*threadfn)(void *data))
 {
-	return __svc_create(prog, bufsize, /*npools*/1, ops);
+	return __svc_create(prog, bufsize, 1, threadfn);
 }
 EXPORT_SYMBOL_GPL(svc_create);
 
-struct svc_serv *
-svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
-		  const struct svc_serv_ops *ops)
+/**
+ * svc_create_pooled - Create an RPC service with pooled threads
+ * @prog: the RPC program the new service will handle
+ * @bufsize: maximum message size for @prog
+ * @threadfn: a function to service RPC requests for @prog
+ *
+ * Returns an instantiated struct svc_serv object or NULL.
+ */
+struct svc_serv *svc_create_pooled(struct svc_program *prog,
+				   unsigned int bufsize,
+				   int (*threadfn)(void *data))
 {
 	struct svc_serv *serv;
 	unsigned int npools = svc_pool_map_get();
 
-	serv = __svc_create(prog, bufsize, npools, ops);
+	serv = __svc_create(prog, bufsize, npools, threadfn);
 	if (!serv)
 		goto out_err;
 	return serv;
@@ -736,7 +751,7 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 		if (IS_ERR(rqstp))
 			return PTR_ERR(rqstp);
 
-		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
+		task = kthread_create_on_node(serv->sv_threadfn, rqstp,
 					      node, "%s", serv->sv_name);
 		if (IS_ERR(task)) {
 			svc_exit_thread(rqstp);

Re: [PATCH v2 0/8] Clean up struct svc_serv_ops

[NeilBrown]

On Fri, 18 Feb 2022, Chuck Lever wrote:
> Here is the completed series of patches to remove struct
> svc_serv_ops, as suggested by Neil Brown. The original material was
> introduced several years ago when we planned to convert the RPC
> server to use work queues. That work was never completed.
> 
> Removal now is to eliminate some unnecessary virtual functions
> and to pave the way for the possibility of dynamic nfsd thread
> management.
> 
> The full set of patches has been provisionally applied to my
> for-next branch to enable broad testing. Comments welcome.

All looks good - lots of nice cleanups there.

Thanks,
NeilBrown