Re: [RFC PATCH] iov_iter: Add an iterator-of-iterators

[Trond Myklebust]

> On Mar 22, 2023, at 14:15, David Howells <dhowells@xxxxxxxxxx> wrote:
> 
> Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote:
> 
>> Add an enum iter_type for ITER_ITER ? :-)
> 
> Well, you asked for it...  It's actually fairly straightforward once
> ITER_PIPE is removed.
> 
> ---
> iov_iter: Add an iterator-of-iterators
> 
> Provide an I/O iterator that takes an array of iterators and iterates over
> them in turn.  Then make the sunrpc service code (and thus nfsd) use it.
> 
> In this particular instance, the svc_tcp_sendmsg() sets up an array of
> three iterators: once for the marker+header, one for the body and one
> optional one for the tail, then sets msg_iter to be an
> iterator-of-iterators across them.

Cool! This is something that can be used on the receive side as well, so very useful. I can imagine it might also open up a few more use cases for ITER_XARRAY.

Thanks!
  Trond

_________________________________
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx