lockd: move lockd's grace period handling into its own module

Currently, all of the grace period handling is part of lockd. Eventually
though we'd like to be able to build v4-only servers, at which point
we'll need to put all of this elsewhere.

Move the code itself into fs/nfs_common and have it build a grace.ko
module. Then, rejigger the Kconfig options so that both nfsd and lockd
enable it automatically.

Signed-off-by: Jeff Layton <[e-mail]>

fs/Kconfig

···
 source "fs/nfs/Kconfig"
 source "fs/nfsd/Kconfig"
 
+config GRACE_PERIOD
+	tristate
+
 config LOCKD
 	tristate
 	depends on FILE_LOCKING
+	select GRACE_PERIOD
 
 config LOCKD_V4
 	bool
···
 
 config NFS_COMMON
 	bool
-	depends on NFSD || NFS_FS
+	depends on NFSD || NFS_FS || LOCKD
 	default y
 
 source "net/sunrpc/Kconfig"

fs/lockd/Makefile

···
 obj-$(CONFIG_LOCKD) += lockd.o
 
 lockd-objs-y := clntlock.o clntproc.o clntxdr.o host.o svc.o svclock.o \
-	        svcshare.o svcproc.o svcsubs.o mon.o xdr.o grace.o
+	        svcshare.o svcproc.o svcsubs.o mon.o xdr.o
 lockd-objs-$(CONFIG_LOCKD_V4) += clnt4xdr.o xdr4.o svc4proc.o
 lockd-objs		      := $(lockd-objs-y)

fs/lockd/grace.c fs/nfs_common/grace.c

···
 /*
  * Common code for control of lockd and nfsv4 grace periods.
+ *
+ * Transplanted from lockd code
  */
 
 #include <linux/module.h>
-#include <linux/lockd/bind.h>
 #include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <linux/fs.h>
 
-#include "netns.h"
-
+static int grace_net_id;
 static DEFINE_SPINLOCK(grace_lock);
 
 /**
  * locks_start_grace
+ * @net: net namespace that this lock manager belongs to
  * @lm: who this grace period is for
  *
  * A grace period is a period during which locks should not be given
···
  *
  * This function is called to start a grace period.
  */
-void locks_start_grace(struct net *net, struct lock_manager *lm)
+void
+locks_start_grace(struct net *net, struct lock_manager *lm)
 {
-	struct lockd_net *ln = net_generic(net, lockd_net_id);
+	struct list_head *grace_list = net_generic(net, grace_net_id);
 
 	spin_lock(&grace_lock);
-	list_add(&lm->list, &ln->grace_list);
+	list_add(&lm->list, grace_list);
 	spin_unlock(&grace_lock);
 }
 EXPORT_SYMBOL_GPL(locks_start_grace);
 
 /**
  * locks_end_grace
+ * @net: net namespace that this lock manager belongs to
  * @lm: who this grace period is for
  *
  * Call this function to state that the given lock manager is ready to
···
  * Note that callers count on it being safe to call this more than once,
  * and the second call should be a no-op.
  */
-void locks_end_grace(struct lock_manager *lm)
+void
+locks_end_grace(struct lock_manager *lm)
 {
 	spin_lock(&grace_lock);
 	list_del_init(&lm->list);
···
  * to answer ordinary lock requests, and when they should accept only
  * lock reclaims.
  */
-int locks_in_grace(struct net *net)
+int
+locks_in_grace(struct net *net)
 {
-	struct lockd_net *ln = net_generic(net, lockd_net_id);
+	struct list_head *grace_list = net_generic(net, grace_net_id);
 
-	return !list_empty(&ln->grace_list);
+	return !list_empty(grace_list);
 }
 EXPORT_SYMBOL_GPL(locks_in_grace);
+
+static int __net_init
+grace_init_net(struct net *net)
+{
+	struct list_head *grace_list = net_generic(net, grace_net_id);
+
+	INIT_LIST_HEAD(grace_list);
+	return 0;
+}
+
+static void __net_exit
+grace_exit_net(struct net *net)
+{
+	struct list_head *grace_list = net_generic(net, grace_net_id);
+
+	BUG_ON(!list_empty(grace_list));
+}
+
+static struct pernet_operations grace_net_ops = {
+	.init = grace_init_net,
+	.exit = grace_exit_net,
+	.id   = &grace_net_id,
+	.size = sizeof(struct list_head),
+};
+
+static int __init
+init_grace(void)
+{
+	return register_pernet_subsys(&grace_net_ops);
+}
+
+static void __exit
+exit_grace(void)
+{
+	unregister_pernet_subsys(&grace_net_ops);
+}
+
+MODULE_AUTHOR("Jeff Layton <[e-mail]>");
+MODULE_LICENSE("GPL");
+module_init(init_grace)
+module_exit(exit_grace)

fs/lockd/netns.h

···
 
 	struct delayed_work grace_period_end;
 	struct lock_manager lockd_manager;
-	struct list_head grace_list;
 
 	spinlock_t nsm_clnt_lock;
 	unsigned int nsm_users;

fs/lockd/svc.c

···
 	struct lockd_net *ln = net_generic(net, lockd_net_id);
 
 	INIT_DELAYED_WORK(&ln->grace_period_end, grace_ender);
-	INIT_LIST_HEAD(&ln->grace_list);
+	INIT_LIST_HEAD(&ln->lockd_manager.list);
 	spin_lock_init(&ln->nsm_clnt_lock);
 	return 0;
 }

fs/nfs_common/Makefile

···
 #
 
 obj-$(CONFIG_NFS_ACL_SUPPORT) += nfs_acl.o
-
 nfs_acl-objs := nfsacl.o
+
+obj-$(CONFIG_GRACE_PERIOD) += grace.o

fs/nfsd/Kconfig

···
 	select FS_POSIX_ACL
 	select SUNRPC_GSS
 	select CRYPTO
+	select GRACE_PERIOD
 	help
 	  This option enables support in your system's NFS server for
 	  version 4 of the NFS protocol (RFC 3530).

include/linux/proc_fs.h

···
 
 #endif /* CONFIG_PROC_FS */
 
+struct net;
+
 static inline struct proc_dir_entry *proc_net_mkdir(
 	struct net *net, const char *name, struct proc_dir_entry *parent)
 {