NFSD: Split linux/nfs_ssc.h

The nfs_ssc.h header contains both client- and server-side data
structures, which means each of those implementations has to pull in
headers from the other.

Create a linux/nfsd_ssc.h for the server side APIs which no longer
includes uapi/linux/nfs.h either directly or indirectly. Because
nfsd_ssc.h drops the transitive include of the NFS client headers,
fs/nfsd/nfs4proc.c now includes <linux/pagemap.h> directly for
filemap_check_wb_err().

struct nfsd4_ssc_umount_item is private to nfsd. Move it into
fs/nfsd/xdr4.h alongside its only consumers rather than into the
exported nfsd_ssc.h.

As an added clean-up, add missing header guard macros and the
struct file and struct vfsmount forward declarations the server
prototypes need.

Cc: Olga Kornievskaia <okorniev@redhat.com>
Cc: Dai Ngo <dai.ngo@oracle.com>
Link: https://patch.msgid.link/20260721162306.894558-5-cel@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>

2 files changed, 49 insertions, 34 deletions

diff --git a/include/linux/nfs_ssc.h b/include/linux/nfs_ssc.h
index b392d56a4dc2..c199ea23e7eb 100644
--- a/include/linux/nfs_ssc.h
+++ b/include/linux/nfs_ssc.h
@@ -2,17 +2,22 @@
 /*
  * include/linux/nfs_ssc.h
  *
+ * NFSv4.2 server-to-server copy, NFS client side APIs
+ *
  * Author: Dai Ngo <dai.ngo@oracle.com>
  *
  * Copyright (c) 2020, Oracle and/or its affiliates.
  */
 
-#include <linux/nfs_fs.h>
-#include <linux/sunrpc/svc.h>
+#ifndef _LINUX_NFS_SSC_H
+#define _LINUX_NFS_SSC_H
+
+#include <linux/nfs_fh.h>
+#include <linux/nfs4.h>
+
+struct file;
+struct vfsmount;
 
-/*
- * NFS_V4
- */
 struct nfs4_ssc_client_ops {
 	struct module *owner;
 	struct file *(*sco_open)(struct vfsmount *ss_mnt,
@@ -26,32 +31,4 @@ extern void nfs42_ssc_unregister_ops(void);
 extern void nfs42_ssc_register(const struct nfs4_ssc_client_ops *ops);
 extern void nfs42_ssc_unregister(const struct nfs4_ssc_client_ops *ops);
 
-#if IS_ENABLED(CONFIG_NFS_V4_2_SSC_HELPER)
-struct file *nfsd42_ssc_open(struct vfsmount *ss_mnt, struct nfs_fh *src_fh,
-			     nfs4_stateid *stateid);
-void nfsd42_ssc_close(struct file *filp);
-#else
-static inline struct file *nfsd42_ssc_open(struct vfsmount *ss_mnt,
-					   struct nfs_fh *src_fh,
-					   nfs4_stateid *stateid)
-{
-	return ERR_PTR(-EIO);
-}
-
-static inline void nfsd42_ssc_close(struct file *filp)
-{
-}
-#endif
-
-struct nfsd4_ssc_umount_item {
-	struct list_head nsui_list;
-	bool nsui_busy;
-	/*
-	 * nsui_refcnt inited to 2, 1 on list and 1 for consumer. Entry
-	 * is removed when refcnt drops to 1 and nsui_expire expires.
-	 */
-	refcount_t nsui_refcnt;
-	unsigned long nsui_expire;
-	struct vfsmount *nsui_vfsmount;
-	char nsui_ipaddr[RPC_MAX_ADDRBUFLEN + 1];
-};
+#endif /* _LINUX_NFS_SSC_H */
diff --git a/include/linux/nfsd_ssc.h b/include/linux/nfsd_ssc.h
new file mode 100644
index 000000000000..7001410f01c2
--- /dev/null
+++ b/include/linux/nfsd_ssc.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * include/linux/nfsd_ssc.h
+ *
+ * NFSv4.2 server-to-server copy, NFS server side APIs
+ *
+ * Author: Dai Ngo <dai.ngo@oracle.com>
+ *
+ * Copyright (c) 2020, Oracle and/or its affiliates.
+ */
+
+#ifndef _LINUX_NFSD_SSC_H
+#define _LINUX_NFSD_SSC_H
+
+#include <linux/nfs_fh.h>
+#include <linux/nfs4.h>
+
+struct file;
+struct vfsmount;
+
+#if IS_ENABLED(CONFIG_NFS_V4_2_SSC_HELPER)
+struct file *nfsd42_ssc_open(struct vfsmount *ss_mnt, struct nfs_fh *src_fh,
+			     nfs4_stateid *stateid);
+void nfsd42_ssc_close(struct file *filp);
+#else
+static inline struct file *nfsd42_ssc_open(struct vfsmount *ss_mnt,
+					   struct nfs_fh *src_fh,
+					   nfs4_stateid *stateid)
+{
+	return ERR_PTR(-EIO);
+}
+
+static inline void nfsd42_ssc_close(struct file *filp)
+{
+}
+#endif
+
+#endif /* _LINUX_NFSD_SSC_H */