[Drbd-dev] [PATCH 27/33] sctp: export sctp_setsockopt_bindx

[David Howells]

Christoph Hellwig <hch at lst.de> wrote:

> > The advantage on using kernel_setsockopt here is that sctp module will
> > only be loaded if dlm actually creates a SCTP socket.  With this
> > change, sctp will be loaded on setups that may not be actually using
> > it. It's a quite big module and might expose the system.
> 
> True.  Not that the intent is to kill kernel space callers of setsockopt,
> as I plan to remove the set_fs address space override used for it.

For getsockopt, does it make sense to have the core kernel load optval/optlen
into a buffer before calling the protocol driver?  Then the driver need not
see the userspace pointer at all.

Similar could be done for setsockopt - allocate a buffer of the size requested
by the user inside the kernel and pass it into the driver, then copy the data
back afterwards.

David