Merge branch 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Merge branch 'work.epoll' of git://git./linux/kernel/git/viro/vfs

Pull epoll updates from Al Viro:
 "Deal with epoll loop check/removal races sanely (among other things).

  The solution merged last cycle (pinning a bunch of struct file
  instances) had been forced by the wrong data structures; untangling
  that takes a bunch of preparations, but it's worth doing - control
  flow in there is ridiculously overcomplicated. Memory footprint has
  also gone down, while we are at it.

  This is not all I want to do in the area, but since I didn't get
  around to posting the followups they'll have to wait for the next
  cycle"

* 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (27 commits)
  epoll: take epitem list out of struct file
  epoll: massage the check list insertion
  lift rcu_read_lock() into reverse_path_check()
  convert ->f_ep_links/->fllink to hlist
  ep_insert(): move creation of wakeup source past the fl_ep_links insertion
  fold ep_read_events_proc() into the only caller
  take the common part of ep_eventpoll_poll() and ep_item_poll() into helper
  ep_insert(): we only need tep->mtx around the insertion itself
  ep_insert(): don't open-code ep_remove() on failure exits
  lift locking/unlocking ep->mtx out of ep_{start,done}_scan()
  ep_send_events_proc(): fold into the caller
  lift the calls of ep_send_events_proc() into the callers
  lift the calls of ep_read_events_proc() into the callers
  ep_scan_ready_list(): prepare to splitup
  ep_loop_check_proc(): saner calling conventions
  get rid of ep_push_nested()
  ep_loop_check_proc(): lift pushing the cookie into callers
  clean reverse_path_check_proc() a bit
  reverse_path_check_proc(): don't bother with cookies
  reverse_path_check_proc(): sane arguments
  ...