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 ddd5b36..b7ca73e 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1173,6 +1173,37 @@
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.
*/