> -----Original Message----- > From: Jason Gunthorpe [mailto:jgunthorpe@xxxxxxxxxxxxxxxxxxxx] > Sent: Tuesday, June 30, 2015 11:21 AM > To: Steve Wise > Cc: dledford@xxxxxxxxxx; roid@xxxxxxxxxxxx; sagig@xxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx; infinipath@xxxxxxxxx; > eli@xxxxxxxxxxxx; ogerlitz@xxxxxxxxxxxx; sean.hefty@xxxxxxxxx > Subject: Re: [PATCH V2 3/5] RDMA/core: transport-independent access flags > > On Mon, Jun 29, 2015 at 04:36:18PM -0500, Steve Wise wrote: > > +int rdma_device_access_flags(struct ib_pd *pd, int roles, int attrs) > > +{ > > + int access_flags = attrs; > > No RDMA_MRR_SEND ? > Send need no explicit access flags. There is no LOCAL_READ access flag. > > + if (roles & RDMA_MRR_RECV) > > + access_flags |= IB_ACCESS_LOCAL_WRITE; > > + > > + if (roles & RDMA_MRR_WRITE_DEST) > > + access_flags |= IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; > > Is IB_ACCESS_LOCAL_WRITE needed? > Yes. You must have LOCAL_WRITE if you set REMOTE_WRITE. > > + if (roles & RDMA_MRR_READ_DEST) { > > + access_flags |= IB_ACCESS_LOCAL_WRITE; > > + if (rdma_protocol_iwarp(pd->device, > > + rdma_start_port(pd->device))) > > + access_flags |= IB_ACCESS_REMOTE_WRITE; > > + } > > So on iWarp if I want to issue a RDMA_READ then I have to allow the > far side uncontrolled write access to the same memory? Is there > something else protecting it? > Only the fact that the rkey of your MR setup for MRR_READ_DEST doesn't have to be advertised to the peer application. So the peer app doesn't know what the rkey is. But the fact is that an MR with REMOTE_WRITE access flags can be used as the destination of RDMA reads and RDMA writes for iWARP. Steve. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
