Re: [PATCH 6/6] fs: replace f_ops->get_poll_head with a static ->f_poll_head pointer

On Thu, Jun 28, 2018 at 10:30:27PM +0100, Al Viro wrote:

quoted

Because I think that what it can do is simply to do the ->poll() calls
outside the iocb locks, and then just attach the poll table to the
kioctx afterwards.

I'd do a bit more - embed the first poll_table_entry into poll iocb itself,
so that the instances that use only one queue wouldn't need any allocations
at all.

No need for poll_table_entry, we just need a wait_queue_head.
poll_table_entry is an select.c internal (except for two nasty driver) -
neither epoll nor most in-kernel callers use it.