Re: sendfile from 9p fs into af_alg

[Al Viro]

On Tue, Nov 22, 2016 at 08:55:59PM -0800, Alexei Starovoitov wrote:
> On Wed, Nov 23, 2016 at 04:46:26AM +0000, Al Viro wrote:
> > On Tue, Nov 22, 2016 at 07:58:29PM -0800, Alexei Starovoitov wrote:
> > > Hi Al,
> > > 
> > > it seems the following commit 523ac9afc73a ("switch default_file_splice_read() to use of pipe-backed iov_iter")
> > > breaks sendfile from 9p fs into af_alg socket.
> > > sendfile into af_alg is used by iproute2/tc.
> > > I'm not sure whether it's 9p or crypto or vfs problem, but happy to test any patches.
> > 
> > Could you try -rc6 (or anything that contains 680bb946a1ae04, for that
> > matter)?
> 
> already tested with that patch in the latest net-next. Still broken :(

Joy...  Which transport are you using there?  The interesting part is
whether it's zerocopy or non-zerocopy path in p9_client_read()...