xprtrdma: Introduce helpers for allocating MWs

We eventually want to handle allocating MWs one at a time, as
needed, instead of grabbing 64 and throwing them at each RPC in the
pipeline.

Add a helper for grabbing an MW off rb_mws, and a helper for
returning an MW to rb_mws. These will be used in a subsequent patch.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Reviewed-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index ddd5b362da357a1ddddedb3137aae1597ef68aaf..b7ca73e7e2e63fe5c4d30a9033213e9d52f18d36 100644 (file)
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1173,6 +1173,37 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
        kfree(buf->rb_pool);
 }
 
+struct rpcrdma_mw *
+rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
+{
+       struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
+       struct rpcrdma_mw *mw = NULL;
+       unsigned long flags;
+
+       spin_lock_irqsave(&buf->rb_lock, flags);
+       if (!list_empty(&buf->rb_mws)) {
+               mw = list_first_entry(&buf->rb_mws,
+                                     struct rpcrdma_mw, mw_list);
+               list_del_init(&mw->mw_list);
+       }
+       spin_unlock_irqrestore(&buf->rb_lock, flags);
+
+       if (!mw)
+               pr_err("RPC:       %s: no MWs available\n", __func__);
+       return mw;
+}
+
+void
+rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
+{
+       struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
+       unsigned long flags;
+
+       spin_lock_irqsave(&buf->rb_lock, flags);
+       list_add_tail(&mw->mw_list, &buf->rb_mws);
+       spin_unlock_irqrestore(&buf->rb_lock, flags);
+}
+
 /* "*mw" can be NULL when rpcrdma_buffer_get_mrs() fails, leaving
  * some req segments uninitialized.
  */

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 300423dea19c508d12e5c9d06e517e9dd5e16884..5b801d561e52a28b47e73a7e82da3da91752de71 100644 (file)
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -413,6 +413,8 @@ int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
 
+struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
+void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 void rpcrdma_buffer_put(struct rpcrdma_req *);
 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);