[PATCH 7/9] NFSD: Relocate nfsd_user_namespace()

[Chuck Lever <cel@kernel.org>]

Refactor: nfsd_user_namespace() currently lives in nfsd.h, so every
caller must pull in nfsd.h -- directly or transitively via state.h --
and with it the NFS protocol definitions from uapi/linux/nfs.h and
friends, even when the caller uses nothing else from nfsd.h.

Since nfsd_user_namespace() is an auth-related function, move it
to fs/nfsd/auth.c in preparation for removing '#include "nfsd.h"'
from a few places.

Signed-off-by: Chuck Lever <cel@kernel.org>
---
 fs/nfsd/auth.c      | 18 ++++++++++++++++++
 fs/nfsd/auth.h      |  6 ++++++
 fs/nfsd/nfs4idmap.c |  1 +
 fs/nfsd/nfs4xdr.c   |  1 +
 fs/nfsd/nfsd.h      |  6 ------
 5 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index e3b4a35caac6..5ef9a0466eda 100644
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -88,3 +88,21 @@ int nfsd_setuser(struct svc_cred *cred, struct svc_export *exp)
 	return -ENOMEM;
 }
 
+/**
+ * nfsd_user_namespace - Get user_namespace in effect for an RPC request
+ * @rqstp: RPC execution context
+ *
+ * xpt_cred is set once at transport creation and never modified. The
+ * transport itself is reference-counted during request processing, so
+ * no explicit reference on the namespace is necessary.
+ *
+ * Return: the user_namespace from the transport credential, or
+ * init_user_ns if no credential was set. The returned namespace pointer
+ * is valid for the duration of the RPC request.
+ */
+struct user_namespace *nfsd_user_namespace(const struct svc_rqst *rqstp)
+{
+	const struct cred *cred = rqstp->rq_xprt->xpt_cred;
+
+	return cred ? cred->user_ns : &init_user_ns;
+}
diff --git a/fs/nfsd/auth.h b/fs/nfsd/auth.h
index 8c5031bbbcee..832bc957980d 100644
--- a/fs/nfsd/auth.h
+++ b/fs/nfsd/auth.h
@@ -8,10 +8,16 @@
 #ifndef LINUX_NFSD_AUTH_H
 #define LINUX_NFSD_AUTH_H
 
+struct user_namespace;
+struct svc_export;
+struct svc_rqst;
+
 /*
  * Set the current process's fsuid/fsgid etc to those of the NFS
  * client user
  */
 int nfsd_setuser(struct svc_cred *cred, struct svc_export *exp);
 
+struct user_namespace *nfsd_user_namespace(const struct svc_rqst *rqstp);
+
 #endif /* LINUX_NFSD_AUTH_H */
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 71ba61b5d0a3..e9faf8b78f74 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -38,6 +38,7 @@
 #include <linux/slab.h>
 #include <linux/sunrpc/svc_xprt.h>
 #include <net/net_namespace.h>
+#include "auth.h"
 #include "idmap.h"
 #include "nfsd.h"
 #include "netns.h"
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index aef48fb0fac2..cba2e72d616c 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -47,6 +47,7 @@
 
 #include <uapi/linux/xattr.h>
 
+#include "auth.h"
 #include "idmap.h"
 #include "acl.h"
 #include "xdr4.h"
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 0503ee0e1bbe..81312b11b5c2 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -153,12 +153,6 @@ static inline int nfsd_v4client(struct svc_rqst *rq)
 {
 	return rq && rq->rq_prog == NFS_PROGRAM && rq->rq_vers == 4;
 }
-static inline struct user_namespace *
-nfsd_user_namespace(const struct svc_rqst *rqstp)
-{
-	const struct cred *cred = rqstp->rq_xprt->xpt_cred;
-	return cred ? cred->user_ns : &init_user_ns;
-}
 
 /* 
  * NFSv4 State
-- 
2.54.0