On 2/9/19 10:13 PM, Jens Axboe wrote:

This is basically a direct port of bfe4037e722e, which implements a
one-shot poll command through aio. Description below is based on that
commit as well. However, instead of adding a POLL command and relying
on io_cancel(2) to remove it, we mimic the epoll(2) interface of
having a command to add a poll notification, IORING_OP_POLL_ADD,
and one to remove it again, IORING_OP_POLL_REMOVE.

To poll for a file descriptor the application should submit an sqe of
type IORING_OP_POLL. It will poll the fd for the events specified in the
poll_events field.

Unlike poll or epoll without EPOLLONESHOT this interface always works in
one shot mode, that is once the sqe is completed, it will have to be
resubmitted.

Based-on-code-from: Christoph Hellwig [off-list ref]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
  fs/io_uring.c                 | 261 +++++++++++++++++++++++++++++++++-
  include/uapi/linux/io_uring.h |   3 +
  2 files changed, 263 insertions(+), 1 deletion(-)

I still would like to be able to properly terminate the I/O on 
aio_cancel. But this can probably be done in a later patch.

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes

--
To unsubscribe, send a message with 'unsubscribe linux-aio' in
the body to majordomo@kvack.org.  For more info on Linux AIO,
see: http://www.kvack.org/aio/
Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>