Re: [PATCH net-next 0/4] mm,tcp: provide mmap_hook to solve lockdep issue

[Christoph Hellwig]

On Fri, Apr 20, 2018 at 08:55:38AM -0700, Eric Dumazet wrote:
> This patch series provide a new mmap_hook to fs willing to grab
> a mutex before mm->mmap_sem is taken, to ensure lockdep sanity.
> 
> This hook allows us to shorten tcp_mmap() execution time (while mmap_sem
> is held), and improve multi-threading scalability. 

Missing CC to linu-fsdevel and linux-mm that will have to decide.

We've rejected this approach multiple times before, so you better
make a really good argument for it.

introducing a multiplexer that overloads a single method certainly
doesn't help making that case.