net/9p: detect invalid options as much as possible

Currently when detecting invalid options in option parsing, some
options(e.g.  msize) just set errno and allow to continuously validate
other options so that it can detect invalid options as much as possible
and give proper error messages together.

This patch applies same rule to option 'trans' and 'version' when
detecting -EINVAL.

Link: http://lkml.kernel.org/r/1525340676-34072-1-git-send-email-cgxu519@gmx.com
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net/9p/client.c

@@ -198,8 +198,6 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 				pr_info("Could not find request transport: %s\n",
 					s);
 				ret = -EINVAL;
-				kfree(s);
-				goto free_and_return;
 			}
 			kfree(s);
 			break;
@@ -214,13 +212,12 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 					 "problem allocating copy of version arg\n");
 				goto free_and_return;
 			}
-			ret = get_protocol_version(s);
-			if (ret == -EINVAL) {
-				kfree(s);
-				goto free_and_return;
-			}
+			r = get_protocol_version(s);
+			if (r < 0)
+				ret = r;
+			else
+				clnt->proto_version = r;
 			kfree(s);
-			clnt->proto_version = ret;
 			break;
 		default:
 			continue;