Re: [PATCH] x86/uaccess: small optimization in unsafe_copy_to_user()

[Linus Torvalds]

On Sat, Apr 17, 2021 at 1:35 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> No, wait - we have non-NULL buf->prev_reclen, so we'll hit
> with buf->error completely ignored.  Nevermind.

Yeah, I'm pretty sure I even tested that -EINTR case at one point.

Of course, it could easily have gotten broken again, so that's not a
strong argument.

That said, the "buf->err" handling has always been very confusing, and
it would be lovely to get rid of that confusion.

I don't remember why we did it that way, but I think it's because
low-level filesystems ended up changing the error that the filldir()
function returned or something like that.

         Linus