xprtrdma: No direct data placement with krb5i and krb5p
authorChuck Lever <chuck.lever@oracle.com>
Wed, 29 Jun 2016 17:55:06 +0000 (13:55 -0400)
committerAnna Schumaker <Anna.Schumaker@Netapp.com>
Mon, 11 Jul 2016 19:50:43 +0000 (15:50 -0400)
commit65b80179f9b8171b74625febf3457f41e792fa23
tree91ed3dcb91c5bab4967ddfdf85132bb7b579a700
parent64695bde6c289a62250eb0a078916703c8cf639a
xprtrdma: No direct data placement with krb5i and krb5p

Direct data placement is not allowed when using flavors that
guarantee integrity or privacy. When such security flavors are in
effect, don't allow the use of Read and Write chunks for moving
individual data items. All messages larger than the inline threshold
are sent via Long Call or Long Reply.

On my systems (CX-3 Pro on FDR), for small I/O operations, the use
of Long messages adds only around 5 usecs of latency in each
direction.

Note that when integrity or encryption is used, the host CPU touches
every byte in these messages. Even if it could be used, data
movement offload doesn't buy much in this case.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
include/linux/sunrpc/auth.h
include/linux/sunrpc/gss_api.h
net/sunrpc/auth_gss/auth_gss.c
net/sunrpc/auth_gss/gss_krb5_mech.c
net/sunrpc/auth_gss/gss_mech_switch.c
net/sunrpc/xprtrdma/rpc_rdma.c