[PATCH 15/24] link_path_walk: final preparations to killing recursion

Al Viro
2015-04-20T18:14:51Z

From: Al Viro <viro@zeniv.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@zeniv.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 9cef3c0..6d79e00 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1773,7 +1773,7 @@ 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(;;) {
@@ -1816,7 +1816,7 @@ 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.
@@ -1825,12 +1825,12 @@ 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, &next, LOOKUP_FOLLOW);
Walked:
if (err < 0)
- return err;
+ goto Err;

if (err) {
struct path link;
@@ -1840,7 +1840,8 @@ Walked:
if (unlikely(nd->link_count >= MAX_NESTED_LINKS)) {
path_put_conditional(&next, nd);
path_put(&nd->path);
- return -ELOOP;
+ err = -ELOOP;
+ goto Err;
}
BUG_ON(nd->depth >= MAX_NESTED_LINKS);

@@ -1854,7 +1855,7 @@ Walked:
err = PTR_ERR(s);
nd->link_count--;
nd->depth--;
- return err;
+ goto Err;
}
err = 0;
if (unlikely(!s)) {
@@ -1877,7 +1878,7 @@ Walked:
put_link(nd, &link, cookie);
nd->link_count--;
nd->depth--;
- return err;
+ goto Err;
} else {
err = walk_component(nd, &next, LOOKUP_FOLLOW);
put_link(nd, &link, cookie);
@@ -1893,7 +1894,10 @@ 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