do_nfs4_mount(): switch to vfs_parse_fs_string()

Reviewed-by: Christian Brauner <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

fs/nfs/nfs4super.c

···
 	struct fs_context *root_fc;
 	struct vfsmount *root_mnt;
 	struct dentry *dentry;
-	size_t len;
+	char *source;
 	int ret;
-
-	struct fs_parameter param = {
-		.key	= "source",
-		.type	= fs_value_is_string,
-		.dirfd	= -1,
-	};
-
-	struct fs_parameter param_fsc = {
-		.key	= "fsc",
-		.type	= fs_value_is_string,
-		.dirfd	= -1,
-	};
 
 	if (IS_ERR(server))
 		return PTR_ERR(server);
···
 	root_ctx->server = server;
 
 	if (ctx->fscache_uniq) {
-		len = strlen(ctx->fscache_uniq);
-		param_fsc.size = len;
-		param_fsc.string = kmemdup_nul(ctx->fscache_uniq, len, GFP_KERNEL);
-		if (param_fsc.string == NULL) {
-			put_fs_context(root_fc);
-			return -ENOMEM;
-		}
-		ret = vfs_parse_fs_param(root_fc, &param_fsc);
-		kfree(param_fsc.string);
+		ret = vfs_parse_fs_string(root_fc, "fsc", ctx->fscache_uniq);
 		if (ret < 0) {
 			put_fs_context(root_fc);
 			return ret;
···
 	}
 	/* We leave export_path unset as it's not used to find the root. */
 
-	len = strlen(hostname) + 5;
-	param.string = kmalloc(len, GFP_KERNEL);
-	if (param.string == NULL) {
+	/* Does hostname needs to be enclosed in brackets? */
+	if (strchr(hostname, ':'))
+		source = kasprintf(GFP_KERNEL, "[%s]:/", hostname);
+	else
+		source = kasprintf(GFP_KERNEL, "%s:/", hostname);
+
+	if (!source) {
 		put_fs_context(root_fc);
 		return -ENOMEM;
 	}
-
-	/* Does hostname needs to be enclosed in brackets? */
-	if (strchr(hostname, ':'))
-		param.size = snprintf(param.string, len, "[%s]:/", hostname);
-	else
-		param.size = snprintf(param.string, len, "%s:/", hostname);
-	ret = vfs_parse_fs_param(root_fc, &param);
-	kfree(param.string);
+	ret = vfs_parse_fs_string(root_fc, "source", source);
+	kfree(source);
 	if (ret < 0) {
 		put_fs_context(root_fc);
 		return ret;