On Thu, May 21, 2020 at 10:34:42AM +0200, Christoph Hellwig wrote:

On Wed, May 20, 2020 at 08:39:13PM -0300, Marcelo Ricardo Leitner wrote:

quoted

On Wed, May 20, 2020 at 04:23:55PM -0700, David Miller wrote:

quoted

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Wed, 20 May 2020 20:10:01 -0300

quoted

The duplication with sctp_setsockopt_nodelay() is quite silly/bad.
Also, why have the 'true' hardcoded? It's what dlm uses, yes, but the
API could be a bit more complete than that.

The APIs are being designed based upon what in-tree users actually
make use of.  We can expand things later if necessary.

Sometimes expanding things later can be though, thus why the worry.
But ok, I get it. Thanks.

The comment still applies, though. (re the duplication)

Where do you see duplication?

sctp_setsockopt_nodelay does the following things:

 - verifies optlen, returns -EINVAL if it doesn't match
 - calls get_user, returns -EFAULT on error
 - converts the value from get_user to a boolean and assigns it
   to sctp_sk(sk)->nodelay
 - returns 0.

sctp_sock_set_nodelay does:

 - call lock_sock
 - assign true to sctp_sk(sk)->nodelay
 - call release_sock
 - does not return an error code

With the patch there are now two ways of enabling nodelay. It may be
just a boolean set today, but if one wants to probe on it or if we
want to extend it with anything, say a debug msg, we have to do it in
two (very different) places.