new helper: get_tree_keyed()

For vfs_get_keyed_super users.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/nfsd/nfsctl.c

@@ -1386,8 +1386,7 @@ static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc)
 
 static int nfsd_fs_get_tree(struct fs_context *fc)
 {
-	fc->s_fs_info = get_net(fc->net_ns);
-	return vfs_get_super(fc, vfs_get_keyed_super, nfsd_fill_super);
+	return get_tree_keyed(fc, nfsd_fill_super, get_net(fc->net_ns));
 }
 
 static void nfsd_fs_free_fc(struct fs_context *fc)

fs/proc/root.c

@@ -157,8 +157,7 @@ static int proc_get_tree(struct fs_context *fc)
 {
 	struct proc_fs_context *ctx = fc->fs_private;
 
-	fc->s_fs_info = ctx->pid_ns;
-	return vfs_get_super(fc, vfs_get_keyed_super, proc_fill_super);
+	return get_tree_keyed(fc, proc_fill_super, ctx->pid_ns);
 }
 
 static void proc_fs_context_free(struct fs_context *fc)

fs/super.c

@@ -1211,6 +1211,16 @@ int get_tree_single(struct fs_context *fc,
 }
 EXPORT_SYMBOL(get_tree_single);
 
+int get_tree_keyed(struct fs_context *fc,
+		  int (*fill_super)(struct super_block *sb,
+				    struct fs_context *fc),
+		void *key)
+{
+	fc->s_fs_info = key;
+	return vfs_get_super(fc, vfs_get_keyed_super, fill_super);
+}
+EXPORT_SYMBOL(get_tree_keyed);
+
 #ifdef CONFIG_BLOCK
 static int set_bdev_super(struct super_block *s, void *data)
 {

include/linux/fs_context.h

@@ -136,7 +136,7 @@ extern int vfs_get_tree(struct fs_context *fc);
 extern void put_fs_context(struct fs_context *fc);
 
 /*
- * sget() wrapper to be called from the ->get_tree() op.
+ * sget() wrappers to be called from the ->get_tree() op.
  */
 enum vfs_get_super_keying {
 	vfs_get_single_super,	/* Only one such superblock may exist */
@@ -147,12 +147,17 @@ extern int vfs_get_super(struct fs_context *fc,
 			 enum vfs_get_super_keying keying,
 			 int (*fill_super)(struct super_block *sb,
 					   struct fs_context *fc));
+
 extern int get_tree_nodev(struct fs_context *fc,
 			 int (*fill_super)(struct super_block *sb,
 					   struct fs_context *fc));
 extern int get_tree_single(struct fs_context *fc,
 			 int (*fill_super)(struct super_block *sb,
 					   struct fs_context *fc));
+extern int get_tree_keyed(struct fs_context *fc,
+			 int (*fill_super)(struct super_block *sb,
+					   struct fs_context *fc),
+			 void *key);
 
 extern const struct file_operations fscontext_fops;
 

ipc/mqueue.c

@@ -364,8 +364,7 @@ static int mqueue_get_tree(struct fs_context *fc)
 {
 	struct mqueue_fs_context *ctx = fc->fs_private;
 
-	fc->s_fs_info = ctx->ipc_ns;
-	return vfs_get_super(fc, vfs_get_keyed_super, mqueue_fill_super);
+	return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
 }
 
 static void mqueue_fs_context_free(struct fs_context *fc)

net/sunrpc/rpc_pipe.c

@@ -1416,8 +1416,7 @@ EXPORT_SYMBOL_GPL(gssd_running);
 
 static int rpc_fs_get_tree(struct fs_context *fc)
 {
-	fc->s_fs_info = get_net(fc->net_ns);
-	return vfs_get_super(fc, vfs_get_keyed_super, rpc_fill_super);
+	return get_tree_keyed(fc, rpc_fill_super, get_net(fc->net_ns));
 }
 
 static void rpc_fs_free_fc(struct fs_context *fc)