linux-kernel - [PATCH 43/79] link_path_walk: final preparations to killing recursion

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Date:	Tue,  5 May 2015 06:22:17 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Neil Brown <neilb@...e.de>, Christoph Hellwig <hch@...radead.org>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 43/79] link_path_walk: final preparations to killing recursion

From: Al Viro <viro@...iv.linux.org.uk>

reduce the number of returns in there - turn all places
where it returns zero into goto OK and places where it
returns non-zero into goto Err.  The only non-trivial
detail is that all breaks in the loop are guaranteed
to be with non-zero err.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/namei.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index b740f6f..ac73d9e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1708,7 +1708,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 	while (*name=='/')
 		name++;
 	if (!*name)
-		return 0;
+		goto OK;
 
 	/* At this point we know we have a real path component. */
 	for(;;) {
@@ -1751,7 +1751,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 
 		name += hashlen_len(hash_len);
 		if (!*name)
-			return 0;
+			goto OK;
 		/*
 		 * If it wasn't NUL, we know it was '/'. Skip that
 		 * slash, and continue until no more slashes.
@@ -1760,12 +1760,12 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 			name++;
 		} while (unlikely(*name == '/'));
 		if (!*name)
-			return 0;
+			goto OK;
 
 		err = walk_component(nd, LOOKUP_FOLLOW);
 Walked:
 		if (err < 0)
-			return err;
+			goto Err;
 
 		if (err) {
 			struct path link;
@@ -1775,7 +1775,8 @@ Walked:
 			if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
 				path_put_conditional(&nd->link, nd);
 				path_put(&nd->path);
-				return -ELOOP;
+				err = -ELOOP;
+				goto Err;
 			}
 			BUG_ON(nd->depth >= MAX_NESTED_LINKS);
 
@@ -1789,7 +1790,7 @@ Walked:
 				err = PTR_ERR(s);
 				current->link_count--;
 				nd->depth--;
-				return err;
+				goto Err;
 			}
 			err = 0;
 			if (unlikely(!s)) {
@@ -1812,7 +1813,7 @@ Walked:
 					put_link(nd, &link, cookie);
 					current->link_count--;
 					nd->depth--;
-					return err;
+					goto Err;
 				} else {
 					err = walk_component(nd, LOOKUP_FOLLOW);
 					put_link(nd, &link, cookie);
@@ -1828,7 +1829,10 @@ Walked:
 		}
 	}
 	terminate_walk(nd);
+Err:
 	return err;
+OK:
+	return 0;
 }
 
 static int path_init(int dfd, const struct filename *name, unsigned int flags,
-- 
2.1.4

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