fs/built-in.o: In function `nfs_show_stats':inode.c:(.text+0x15481a): undefined reference to `rpc_print_iostats'
net/built-in.o: In function `rpc_destroy_client': undefined reference to `rpc_free_iostats'
net/built-in.o: In function `rpc_clone_client': undefined reference to `rpc_alloc_iostats'
net/built-in.o: In function `rpc_new_client': undefined reference to `rpc_alloc_iostats'
net/built-in.o: In function `xprt_release': undefined reference to `rpc_count_iostats'
make: *** [.tmp_vmlinux1] Error 1

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Add a simple mechanism for collecting stats in the RPC client.  Stats are
tabulated during xprt_release.  Note that per_cpu shenanigans are not
required here because the RPC client already serializes on the transport
write lock.

Test plan:
Compile kernel with CONFIG_NFS enabled.  Basic performance regression
testing with high-speed networking and high performance server.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>