Re: [PATCH v3 0/2] iov_iter: allow iov_iter_get_pages_alloc to allocate more pages per call

From: Al Viro
Date: Fri Feb 03 2017 - 22:09:33 EST


On Thu, Feb 02, 2017 at 09:51:25AM +0000, Al Viro wrote:

> * fuse_copy_fill(). I'm not at all sure that iov_iter_get_pages()
> is a good idea there - fuse_copy_do() could bloody well just use
> copy_{to,from}_iter().

Miklos, could you explain why does lock_request() prohibit page faults until
the matching unlock_request()? All it does is setting FR_LOCKED on
our request and the only thing that even looks at that is fuse_abort_conn(),
which doesn't (AFAICS) wait for anything.

Where does the deadlock come from, and if it's not a deadlock - what is
it? Or is that comment stale since "fuse: simplify request abort"?