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 <hch@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
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@xxxxxxxx>
Cheers,
Hannes
