On Sun, 2018-09-02 at 19:52 -0700, Linus Torvalds wrote: > On Sun, Sep 2, 2018 at 7:47 PM Linus Torvalds > <torva...@linux-foundation.org> wrote: > > > > The comment actually does talk about it, although the comment also > > claims that the cs read would use load_unaligned_zeropad(), which it > > no longer does (now it only does the read_word_at_a_time). > > IOW, look at commit 12f8ad4b0533 ("vfs: clean up __d_lookup_rcu() and > dentry_cmp() interfaces") for why the zeropad went away for the cs > access (but the comment wasn't updated). > > And then bfe7aa6c39b1 ("fs/dcache: Use read_word_at_a_time() in > dentry_string_cmp()") did the "let's make KASAN happy thing. > > And yes, the word-at-a-time code actually matters a lot for certain > loads. The "copy-and-hash" thing for path components ends up being > pretty critical in all the pathname handling.
Yup, makes sense. Thanks ! Cheers, Ben.