getcwd(2): clean up error handling

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

diff --git a/fs/d_path.c b/fs/d_path.c
index 8a9cd44..23a53f7 100644 (file)
--- a/fs/d_path.c
+++ b/fs/d_path.c
@@ -390,9 +390,11 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
        rcu_read_lock();
        get_fs_root_and_pwd_rcu(current->fs, &root, &pwd);
 
-       error = -ENOENT;
-       if (!d_unlinked(pwd.dentry)) {
-               unsigned long len;
+       if (unlikely(d_unlinked(pwd.dentry))) {
+               rcu_read_unlock();
+               error = -ENOENT;
+       } else {
+               unsigned len;
                DECLARE_BUFFER(b, page, PATH_MAX);
 
                prepend(&b, "", 1);
@@ -400,23 +402,16 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
                        prepend(&b, "(unreachable)", 13);
                rcu_read_unlock();
 
-               if (b.len < 0) {
-                       error = -ENAMETOOLONG;
-                       goto out;
-               }
-
-               error = -ERANGE;
                len = PATH_MAX - b.len;
-               if (len <= size) {
+               if (unlikely(len > PATH_MAX))
+                       error = -ENAMETOOLONG;
+               else if (unlikely(len > size))
+                       error = -ERANGE;
+               else if (copy_to_user(buf, b.buf, len))
+                       error = -EFAULT;
+               else
                        error = len;
-                       if (copy_to_user(buf, b.buf, len))
-                               error = -EFAULT;
-               }
-       } else {
-               rcu_read_unlock();
        }
-
-out:
        __putname(page);
        return error;
 }