[RFC PATCH 0/3] epoll: read(),write(),ioctl() interface

[Nathaniel Yazdani <n1ght.4nd.d4y@gmail.com>]

Hi everyone,

This patch series adds support for read(), write(), and ioctl() operations
on eventpolls as well as an associated userspace structure to format the
eventpoll entries delivered via read()/write() buffers. The new structure,
struct epoll, differs from struct epoll_event mainly in that it also holds
the associated file descriptor. Using the normal I/O interface to manipulate
eventpolls is much neater than using epoll-specific syscalls while also
allowing for greater flexibility (theoretically, pipes could be used to
filter access). Specifically, write() creates, modifies, and/or removes event
entries stored in the supplied buffer, using the userspace identifier to
check whether an entry exists and removing it if no events are set to trigger
it, while read() simply waits for enough events to fill the provided buffer.
As timeout control is essential for polling to be practical, ioctl() is used
to configure an optional timeout, which is infinite by default.

 Documentation/ioctl/ioctl-number.txt |   1 +
 fs/eventpoll.c                       | 534 ++++++++++++++++++++++++-----------
 include/uapi/linux/eventpoll.h       |  10 +
 3 files changed, 384 insertions(+), 161 deletions(-)