[PATCH v1 05/14] xprtrdma: Introduce helpers for allocating MWs

Chuck Lever
2015-05-04T17:57:30Z

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-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
net/sunrpc/xprtrdma/verbs.c | 31 +++++++++++++++++++++++++++++++
net/sunrpc/xprtrdma/xprt_rdma.h | 2 ++
2 files changed, 33 insertions(+)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index ebcb0e2..c21329e 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1179,6 +1179,37 @@ 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 531ad33..7de424e 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -415,6 +415,8 @@ 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 *);

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