SUNRPC: Abstract backchannel operations

xprt_{setup,destroy}_backchannel() won't be adequate for RPC/RMDA
bi-direction. In particular, receive buffers have to be pre-
registered and posted in order to receive incoming backchannel
requests.

Add a virtual function call to allow the insertion of appropriate
backchannel setup and destruction methods for each transport.

In addition, freeing a backchannel request is a little different
for RPC/RDMA. Introduce an rpc_xprt_op to handle the difference.

Signed-off-by: Chuck Lever <chuck.lever@oracle.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>

diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h
index 8df43c9f11dc295889639364101f324150d769ff..4397a4824c819f574f38800efe38d341bd212a15 100644 (file)
--- a/include/linux/sunrpc/bc_xprt.h
+++ b/include/linux/sunrpc/bc_xprt.h
@@ -38,6 +38,11 @@ void xprt_free_bc_request(struct rpc_rqst *req);
 int xprt_setup_backchannel(struct rpc_xprt *, unsigned int min_reqs);
 void xprt_destroy_backchannel(struct rpc_xprt *, unsigned int max_reqs);
 
+/* Socket backchannel transport methods */
+int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs);
+void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs);
+void xprt_free_bc_rqst(struct rpc_rqst *req);
+
 /*
  * Determine if a shared backchannel is in use
  */

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 0fb9acbb478095b576445d74d264ad5e5193a55e..3f79c4a4ce749141b349e0c87aabcc9cec5ca16d 100644 (file)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -136,6 +136,11 @@ struct rpc_xprt_ops {
        int             (*enable_swap)(struct rpc_xprt *xprt);
        void            (*disable_swap)(struct rpc_xprt *xprt);
        void            (*inject_disconnect)(struct rpc_xprt *xprt);
+       int             (*bc_setup)(struct rpc_xprt *xprt,
+                                   unsigned int min_reqs);
+       void            (*bc_free_rqst)(struct rpc_rqst *rqst);
+       void            (*bc_destroy)(struct rpc_xprt *xprt,
+                                     unsigned int max_reqs);
 };
 
 /*

diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 6255d141133bb0ccabc195c8b4d9bce8cbe39c51..229956bf84577f81d380536b76d1e57d16de53ae 100644 (file)
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -137,6 +137,14 @@ out_free:
  * callback requests can be up to 4096 bytes in size.
  */
 int xprt_setup_backchannel(struct rpc_xprt *xprt, unsigned int min_reqs)
+{
+       if (!xprt->ops->bc_setup)
+               return 0;
+       return xprt->ops->bc_setup(xprt, min_reqs);
+}
+EXPORT_SYMBOL_GPL(xprt_setup_backchannel);
+
+int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs)
 {
        struct rpc_rqst *req;
        struct list_head tmp_list;
@@ -192,7 +200,6 @@ out_free:
        dprintk("RPC:       setup backchannel transport failed\n");
        return -ENOMEM;
 }
-EXPORT_SYMBOL_GPL(xprt_setup_backchannel);
 
 /**
  * xprt_destroy_backchannel - Destroys the backchannel preallocated structures.
@@ -204,6 +211,13 @@ EXPORT_SYMBOL_GPL(xprt_setup_backchannel);
  * of reqs specified by the caller.
  */
 void xprt_destroy_backchannel(struct rpc_xprt *xprt, unsigned int max_reqs)
+{
+       if (xprt->ops->bc_destroy)
+               xprt->ops->bc_destroy(xprt, max_reqs);
+}
+EXPORT_SYMBOL_GPL(xprt_destroy_backchannel);
+
+void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs)
 {
        struct rpc_rqst *req = NULL, *tmp = NULL;
 
@@ -227,7 +241,6 @@ out:
        dprintk("RPC:        backchannel list empty= %s\n",
                list_empty(&xprt->bc_pa_list) ? "true" : "false");
 }
-EXPORT_SYMBOL_GPL(xprt_destroy_backchannel);
 
 static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid)
 {
@@ -264,6 +277,13 @@ void xprt_free_bc_request(struct rpc_rqst *req)
 {
        struct rpc_xprt *xprt = req->rq_xprt;
 
+       xprt->ops->bc_free_rqst(req);
+}
+
+void xprt_free_bc_rqst(struct rpc_rqst *req)
+{
+       struct rpc_xprt *xprt = req->rq_xprt;
+
        dprintk("RPC:       free backchannel req=%p\n", req);
 
        req->rq_connect_cookie = xprt->connect_cookie - 1;

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 1a85e0ed0b4841792cd5b6a7d86864cbc2d334a3..44a81e4c6783e4e789fe5c164c55993e1c081ddc 100644 (file)
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2580,6 +2580,11 @@ static struct rpc_xprt_ops xs_tcp_ops = {
        .enable_swap            = xs_enable_swap,
        .disable_swap           = xs_disable_swap,
        .inject_disconnect      = xs_inject_disconnect,
+#ifdef CONFIG_SUNRPC_BACKCHANNEL
+       .bc_setup               = xprt_setup_bc,
+       .bc_free_rqst           = xprt_free_bc_rqst,
+       .bc_destroy             = xprt_destroy_bc,
+#endif
 };
 
 /*