RE: [PATCH 32/33] sctp: add sctp_sock_get_primary_addr

[David Laight]

From: Marcelo Ricardo Leitner
> Sent: 13 May 2020 19:03
> 
> On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote:
> > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel
> > space without going through a fake uaccess.
> 
> Same comment as on the other dlm/sctp patch.

Wouldn't it be best to write sctp_[gs]etsockotp() that
use a kernel buffer and then implement the user-space
calls using a wrapper that does the copies to an on-stack
(or malloced if big) buffer.

That will also simplify the code be removing all the copies
and -EFAULT returns.
Only the size checks will be needed and the code can assume
the buffer is at least the size of the on-stack buffer.

Our SCTP code uses SO_REUSADDR, SCTP_EVENTS, SCTP_NODELAY,
SCTP_STATUS, SCTP_INITMSG, IPV6_ONLY, SCTP_SOCKOPT_BINDX_ADD
and SO_LINGER.

	David

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