tree 5efa63f094f05fcb0cd83899cf0aad0ac7871018
parent 2e532d68a2b3e2aa6b19731501222069735c741c
author Tejun Heo <tj@kernel.org> 1223941525 -0500
committer Eric Van Hensbergen <ericvh@gmail.com> 1224259481 -0500

9p-trans_fd: use single poller

trans_fd used pool of upto 100 pollers to monitor the r/w fds.  The
approach makes sense in userspace back when the only available
interfaces were poll(2) and select(2).  As each event monitor -
trigger - handling iteration took O(n) where `n' is the number of
watched fds, it makes sense to spread them to many pollers such that
the `n' can be divided by the number of pollers.  However, this
doesn't make any sense in kernel because persistent edge triggered
event monitoring is how the whole thing is implemented in the kernel
in the first place.

This patch converts trans_fd to use single poller which watches all
the fds instead of the poll of pollers approach.  All the fds are
registered for monitoring on creation and only the fds with pending
events are scanned when something happens much like how epoll is
implemented.

This change makes trans_fd fd monitoring more efficient and simpler.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>