[PATCH 10/12] sunrpc: introduce get_rpc_pipefs()

["Kirill A. Shutsemov" <kirill@shutemov.name>]

From: Kirill A. Shutemov <kirill@shutemov.name>

Get rpc_pipefs mount point by path.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
---
 include/linux/sunrpc/rpc_pipe_fs.h |    2 ++
 net/sunrpc/rpc_pipe.c              |   24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/include/linux/sunrpc/rpc_pipe_fs.h b/include/linux/sunrpc/rpc_pipe_fs.h
index b09bfa5..922057c 100644
--- a/include/linux/sunrpc/rpc_pipe_fs.h
+++ b/include/linux/sunrpc/rpc_pipe_fs.h
@@ -46,6 +46,8 @@ RPC_I(struct inode *inode)
 
 extern struct vfsmount *init_rpc_pipefs;
 
+struct vfsmount *get_rpc_pipefs(const char *path);
+
 extern int rpc_queue_upcall(struct inode *, struct rpc_pipe_msg *);
 
 struct rpc_clnt;
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index b1e299b..c48f7a5 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -931,6 +931,30 @@ static const struct super_operations s_ops = {
 
 #define RPCAUTH_GSSMAGIC 0x67596969
 
+struct vfsmount *get_rpc_pipefs(const char *p)
+{
+	int error;
+	struct vfsmount *rpcmount;
+	struct path path;
+
+	if (!p)
+		return mntget(init_rpc_pipefs);
+
+	error = kern_path(p, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
+	if (error)
+		return ERR_PTR(error);
+
+	if (path.mnt->mnt_sb->s_magic != RPCAUTH_GSSMAGIC) {
+		path_put(&path);
+		return ERR_PTR(-EINVAL);
+	}
+
+	rpcmount = mntget(path.mnt);
+	path_put(&path);
+
+	return rpcmount;
+}
+
 /*
  * We have a single directory with 1 node in it.
  */
-- 
1.7.3.4