Re: [PATCH 2/2] blkdev: __blkdev_direct_IO_simple: make sure to fill up the bio

On Thu, Jul 19, 2018 at 12:08:41PM +0100, Al Viro wrote:

quoted

Well, there has never been a promise that it will grab *all* pages in the
iter AFAIK. Practically, I think that it was just too hairy to implement in
the macro magic that iter processing is... Al might know more (added to
CC).

Not really - it's more that VM has every right to refuse letting you pin
an arbitrary amount of pages anyway.

In which case the code after this patch isn't going to help either, because
it still tries to pin it all, just in multiple calls to get_user_pages().