Re: [PATCH v2 5/5] sunrpc: turn swapper_enable/disable functions into rpc_xprt_ops

Trond Myklebust
2015-06-03T14:48:12Z

On Wed, Jun 3, 2015 at 10:43 AM, Jeff Layton <jlayton@poochiereds.net> wrote:
> RDMA xprts don't have a sock_xprt, but an rdma_xprt, so the
> xs_swapper_enable/disable functions will likely oops when fed an RDMA
> xprt. Turn these functions into rpc_xprt_ops so that that doesn't
> occur. For now the RDMA versions are no-ops.
>
> Cc: Chuck Lever <chuck.lever@oracle.com>
> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
> ---
> include/linux/sunrpc/xprt.h | 16 ++++++++++++++--
> net/sunrpc/clnt.c | 4 ++--
> net/sunrpc/xprtrdma/transport.c | 15 ++++++++++++++-
> net/sunrpc/xprtsock.c | 31 +++++++++++++++++++++++++------
> 4 files changed, 55 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
> index 26b1624128ec..7eb58610eb94 100644
> --- a/include/linux/sunrpc/xprt.h
> +++ b/include/linux/sunrpc/xprt.h
> @@ -133,6 +133,8 @@ struct rpc_xprt_ops {
> void (*close)(struct rpc_xprt *xprt);
> void (*destroy)(struct rpc_xprt *xprt);
> void (*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
> + int (*enable_swap)(struct rpc_xprt *xprt);
> + void (*disable_swap)(struct rpc_xprt *xprt);
> };
>
> /*
> @@ -327,6 +329,18 @@ static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *
> return p + xprt->tsh_size;
> }
>
> +static inline int
> +xprt_enable_swap(struct rpc_xprt *xprt)
> +{
> + return xprt->ops->enable_swap(xprt);
> +}
> +
> +static inline void
> +xprt_disable_swap(struct rpc_xprt *xprt)
> +{
> + xprt->ops->disable_swap(xprt);
> +}
> +
> /*
> * Transport switch helper functions
> */
> @@ -345,8 +359,6 @@ void xprt_release_rqst_cong(struct rpc_task *task);
> void xprt_disconnect_done(struct rpc_xprt *xprt);
> void xprt_force_disconnect(struct rpc_xprt *xprt);
> void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
> -int xs_swapper_enable(struct rpc_xprt *xprt);
> -void xs_swapper_disable(struct rpc_xprt *xprt);
>
> bool xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
> void xprt_unlock_connect(struct rpc_xprt *, void *);
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index 804a75e71e84..60d1835edb26 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -2492,7 +2492,7 @@ retry:
> goto retry;
> }
>
> - ret = xs_swapper_enable(xprt);
> + ret = xprt_enable_swap(xprt);
> xprt_put(xprt);
> }
> return ret;
> @@ -2519,7 +2519,7 @@ retry:
> goto retry;
> }
>
> - xs_swapper_disable(xprt);
> + xprt_disable_swap(xprt);
> xprt_put(xprt);
> }
> }
> diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
> index 54f23b1be986..e7a157754095 100644
> --- a/net/sunrpc/xprtrdma/transport.c
> +++ b/net/sunrpc/xprtrdma/transport.c
> @@ -682,6 +682,17 @@ static void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
> r_xprt->rx_stats.bad_reply_count);
> }
>
> +static int
> +xprt_rdma_enable_swap(struct rpc_xprt *xprt)
> +{
> + return 0;

Shouldn't the function be returning an error here? What does swapon
expect if the device you are trying to enable doesn't support swap?

> +}
> +
> +static void
> +xprt_rdma_disable_swap(struct rpc_xprt *xprt)
> +{
> +}
> +
> /*
> * Plumbing for rpc transport switch and kernel module
> */
> @@ -700,7 +711,9 @@ static struct rpc_xprt_ops xprt_rdma_procs = {
> .send_request = xprt_rdma_send_request,
> .close = xprt_rdma_close,
> .destroy = xprt_rdma_destroy,
> - .print_stats = xprt_rdma_print_stats
> + .print_stats = xprt_rdma_print_stats,
> + .enable_swap = xprt_rdma_enable_swap,
> + .disable_swap = xprt_rdma_disable_swap,
> };
>
> static struct xprt_class xprt_rdma = {
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index 16aa5dad41b2..b8aaf20aea96 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -1985,14 +1985,14 @@ static void xs_set_memalloc(struct rpc_xprt *xprt)
> }
>
> /**
> - * xs_swapper_enable - Tag this transport as being used for swap.
> + * xs_enable_swap - Tag this transport as being used for swap.
> * @xprt: transport to tag
> *
> * Take a reference to this transport on behalf of the rpc_clnt, and
> * optionally mark it for swapping if it wasn't already.
> */
> -int
> -xs_swapper_enable(struct rpc_xprt *xprt)
> +static int
> +xs_enable_swap(struct rpc_xprt *xprt)
> {
> struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
>
> @@ -2007,14 +2007,14 @@ xs_swapper_enable(struct rpc_xprt *xprt)
> }
>
> /**
> - * xs_swapper_disable - Untag this transport as being used for swap.
> + * xs_disable_swap - Untag this transport as being used for swap.
> * @xprt: transport to tag
> *
> * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
> * swapper refcount goes to 0, untag the socket as a memalloc socket.
> */
> -void
> -xs_swapper_disable(struct rpc_xprt *xprt)
> +static void
> +xs_disable_swap(struct rpc_xprt *xprt)
> {
> struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
>
> @@ -2030,6 +2030,17 @@ xs_swapper_disable(struct rpc_xprt *xprt)
> static void xs_set_memalloc(struct rpc_xprt *xprt)
> {
> }
> +
> +static int
> +xs_enable_swap(struct rpc_xprt *xprt)
> +{
> + return 0;

Ditto.

> +}
> +
> +static void
> +xs_disable_swap(struct rpc_xprt *xprt)
> +{
> +}
> #endif
>
> static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
> @@ -2496,6 +2507,8 @@ static struct rpc_xprt_ops xs_local_ops = {
> .close = xs_close,
> .destroy = xs_destroy,
> .print_stats = xs_local_print_stats,
> + .enable_swap = xs_enable_swap,
> + .disable_swap = xs_disable_swap,
> };
>
> static struct rpc_xprt_ops xs_udp_ops = {
> @@ -2515,6 +2528,8 @@ static struct rpc_xprt_ops xs_udp_ops = {
> .close = xs_close,
> .destroy = xs_destroy,
> .print_stats = xs_udp_print_stats,
> + .enable_swap = xs_enable_swap,
> + .disable_swap = xs_disable_swap,
> };
>
> static struct rpc_xprt_ops xs_tcp_ops = {
> @@ -2531,6 +2546,8 @@ static struct rpc_xprt_ops xs_tcp_ops = {
> .close = xs_tcp_shutdown,
> .destroy = xs_destroy,
> .print_stats = xs_tcp_print_stats,
> + .enable_swap = xs_enable_swap,
> + .disable_swap = xs_disable_swap,
> };
>
> /*
> @@ -2548,6 +2565,8 @@ static struct rpc_xprt_ops bc_tcp_ops = {
> .close = bc_close,
> .destroy = bc_destroy,
> .print_stats = xs_tcp_print_stats,
> + .enable_swap = xs_enable_swap,
> + .disable_swap = xs_disable_swap,
> };
>
> static int xs_init_anyaddr(const int family, struct sockaddr *sap)
> --
> 2.4.2
>