1 files changed, 122 insertions, 0 deletions
diff --git a/include/linux/nfslocalio.h b/include/linux/nfslocalio.h
new file mode 100644
index 000000000000..5c7c92659e73
--- /dev/null
+++ b/include/linux/nfslocalio.h
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com>
+ * Copyright (C) 2024 NeilBrown <neilb@suse.de>
+ */
+#ifndef __LINUX_NFSLOCALIO_H
+#define __LINUX_NFSLOCALIO_H
+
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/uuid.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/svcauth.h>
+#include <linux/nfs.h>
+#include <net/net_namespace.h>
+
+struct nfs_client;
+struct nfs_file_localio;
+
+/*
+ * Useful to allow a client to negotiate if localio
+ * possible with its server.
+ *
+ * See Documentation/filesystems/nfs/localio.rst for more detail.
+ */
+typedef struct {
+	uuid_t uuid;
+	unsigned nfs3_localio_probe_count;
+	/* this struct is over a cacheline, avoid bouncing */
+	spinlock_t ____cacheline_aligned lock;
+	struct list_head list;
+	spinlock_t *list_lock; /* nn->local_clients_lock */
+	struct net __rcu *net; /* nfsd's network namespace */
+	struct auth_domain *dom; /* auth_domain for localio */
+	/* Local files to close when net is shut down or exports change */
+	struct list_head files;
+} nfs_uuid_t;
+
+void nfs_uuid_init(nfs_uuid_t *);
+bool nfs_uuid_begin(nfs_uuid_t *);
+void nfs_uuid_end(nfs_uuid_t *);
+void nfs_uuid_is_local(const uuid_t *, struct list_head *, spinlock_t *,
+		       struct net *, struct auth_domain *, struct module *);
+
+void nfs_localio_enable_client(struct nfs_client *clp);
+void nfs_localio_disable_client(struct nfs_client *clp);
+void nfs_localio_invalidate_clients(struct list_head *nn_local_clients,
+				    spinlock_t *nn_local_clients_lock);
+
+/* localio needs to map filehandle -> struct nfsd_file */
+void nfs_close_local_fh(struct nfs_file_localio *);
+
+struct nfsd_localio_operations {
+	bool (*nfsd_net_try_get)(struct net *);
+	void (*nfsd_net_put)(struct net *);
+	struct nfsd_file *(*nfsd_open_local_fh)(struct net *,
+						struct auth_domain *,
+						struct rpc_clnt *,
+						const struct cred *,
+						const struct nfs_fh *,
+						struct nfsd_file __rcu **pnf,
+						const fmode_t);
+	struct net *(*nfsd_file_put_local)(struct nfsd_file __rcu **);
+	struct nfsd_file *(*nfsd_file_get_local)(struct nfsd_file *);
+	struct file *(*nfsd_file_file)(struct nfsd_file *);
+} ____cacheline_aligned;
+
+extern void nfsd_localio_ops_init(void);
+extern const struct nfsd_localio_operations *nfs_to;
+
+struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *,
+		   struct rpc_clnt *, const struct cred *,
+		   const struct nfs_fh *, struct nfs_file_localio *,
+		   struct nfsd_file __rcu **pnf,
+		   const fmode_t);
+
+static inline void nfs_to_nfsd_net_put(struct net *net)
+{
+	/*
+	 * Once reference to net (and associated nfsd_serv) is dropped, NFSD
+	 * could be unloaded, so ensure safe return from nfsd_net_put() by
+	 * always taking RCU.
+	 */
+	rcu_read_lock();
+	nfs_to->nfsd_net_put(net);
+	rcu_read_unlock();
+}
+
+static inline void nfs_to_nfsd_file_put_local(struct nfsd_file __rcu **localio)
+{
+	/*
+	 * Either *localio must be guaranteed to be non-NULL, or caller
+	 * must prevent nfsd shutdown from completing as nfs_close_local_fh()
+	 * does by blocking the nfs_uuid from being finally put.
+	 */
+	struct net *net;
+
+	net = nfs_to->nfsd_file_put_local(localio);
+
+	if (net)
+		nfs_to_nfsd_net_put(net);
+}
+
+#else   /* CONFIG_NFS_LOCALIO */
+
+struct nfs_file_localio;
+static inline void nfs_close_local_fh(struct nfs_file_localio *nfl)
+{
+}
+static inline void nfsd_localio_ops_init(void)
+{
+}
+struct nfs_client;
+static inline void nfs_localio_disable_client(struct nfs_client *clp)
+{
+}
+
+#endif  /* CONFIG_NFS_LOCALIO */
+
+#endif  /* __LINUX_NFSLOCALIO_H */