On Wed, Mar 21, 2018 at 10:29:26AM +0100, Christoph Hellwig wrote:

On Wed, Mar 21, 2018 at 10:24:43AM +0100, Greg KH wrote:

quoted

On Wed, Mar 21, 2018 at 08:32:31AM +0100, Christoph Hellwig wrote:

quoted

This is the io_getevents equivalent of ppoll/pselect and allows to
properly mix signals and aio completions (especially with IOCB_CMD_POLL)
and atomically executes the following sequence:

	sigset_t origmask;

	pthread_sigmask(SIG_SETMASK, &sigmask, &origmask);
	ret = io_getevents(ctx, min_nr, nr, events, timeout);
	pthread_sigmask(SIG_SETMASK, &origmask, NULL);

Note that unlike many other signal related calls we do not pass a sigmask
size, as that would get us to 7 arguments, which aren't easily supported
by the syscall infrastructure.  It seems a lot less painful to just add a
new syscall variant in the unlikely case we're going to increase the
sigset size.

Do we have a manpage for this new syscall and maybe a test program for
it so we can exercise it as part of the kselftests?

The man page and test cases where submitted to libaio:

http://git.infradead.org/users/hch/libaio.git/shortlog/refs/heads/aio-poll

In the meantime the man page apparently moved to man-pages, I'll do that
work once we make some forward progress.

Great!

quoted

And do we really need a compat thunk for a new syscall?  Ugh, I guess
it's needed due to the long mess, right?  No way to just define it the
same way for both arch sizes?

Not without making it a pain to use.  It should be a drop-in enhancement
to the existing aio abis, which all work on these types.

Ok, make sense, thanks.

greg k-h

--
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>