xprtrdma: Always provide a write list when sending NFS READ
authorChuck Lever <chuck.lever@oracle.com>
Mon, 3 Aug 2015 17:03:58 +0000 (13:03 -0400)
committerAnna Schumaker <Anna.Schumaker@Netapp.com>
Wed, 5 Aug 2015 20:21:27 +0000 (16:21 -0400)
commit02eb57d8f44caa582e297f51f3555d47767c5fe9
tree498f9292c46c4a0a824e82da9d2c9444e59645ca
parent5457ced0b504b41afe9439a6533066dea2fc0e1a
xprtrdma: Always provide a write list when sending NFS READ

The client has been setting up a reply chunk for NFS READs that are
smaller than the inline threshold. This is not efficient: both the
server and client CPUs have to copy the reply's data payload into
and out of the memory region that is then transferred via RDMA.

Using the write list, the data payload is moved by the device and no
extra data copying is necessary.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com>
Reviewed-By: Sagi Grimberg <sagig@mellanox.com>
Tested-by: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
net/sunrpc/xprtrdma/rpc_rdma.c