vfs: stop using user_path_at_empty in do_readlinkat

It is the only consumer and it saddles getname_flags with an argument set
to NULL by everyone else.

Instead the routine can do the empty check on its own.

Then user_path_at_empty can get retired and getname_flags can lose the
argument.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240604155257.109500-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Mateusz Guzik 2024-06-04 17:52:55 +02:00 committed by Christian Brauner
parent ca86a5d2f9
commit 969ce92da3

View File

@ -488,34 +488,39 @@ static int do_readlinkat(int dfd, const char __user *pathname,
char __user *buf, int bufsiz)
{
struct path path;
struct filename *name;
int error;
int empty = 0;
unsigned int lookup_flags = LOOKUP_EMPTY;
if (bufsiz <= 0)
return -EINVAL;
retry:
error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
if (!error) {
struct inode *inode = d_backing_inode(path.dentry);
name = getname_flags(pathname, lookup_flags, NULL);
error = filename_lookup(dfd, name, lookup_flags, &path, NULL);
if (unlikely(error)) {
putname(name);
return error;
}
error = empty ? -ENOENT : -EINVAL;
/*
* AFS mountpoints allow readlink(2) but are not symlinks
*/
if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {
touch_atime(&path);
error = vfs_readlink(path.dentry, buf, bufsiz);
}
}
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
/*
* AFS mountpoints allow readlink(2) but are not symlinks
*/
if (d_is_symlink(path.dentry) ||
d_backing_inode(path.dentry)->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {
touch_atime(&path);
error = vfs_readlink(path.dentry, buf, bufsiz);
}
} else {
error = (name->name[0] == '\0') ? -ENOENT : -EINVAL;
}
path_put(&path);
putname(name);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}