[PATCH 1/8] xprtrdma: RPC/RDMA must invoke xprt_wake_pending_tasks() in process context

Chuck Lever
2014-04-14T22:22:32Z

An IB provider can invoke rpcrdma_conn_func() in an IRQ context,
thus rpcrdma_conn_func() cannot be allowed to directly invoke
generic RPC functions like xprt_wake_pending_tasks().

Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---

net/sunrpc/xprtrdma/rpc_rdma.c | 22 +++++++++++++++-------
net/sunrpc/xprtrdma/verbs.c | 3 +++
net/sunrpc/xprtrdma/xprt_rdma.h | 3 +++
3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 400aa1b..c296468 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -676,15 +676,11 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
rqst->rq_private_buf = rqst->rq_rcv_buf;
}

-/*
- * This function is called when an async event is posted to
- * the connection which changes the connection state. All it
- * does at this point is mark the connection up/down, the rpc
- * timers do the rest.
- */
void
-rpcrdma_conn_func(struct rpcrdma_ep *ep)
+rpcrdma_connect_worker(struct work_struct *work)
{
+ struct rpcrdma_ep *ep =
+ container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
struct rpc_xprt *xprt = ep->rep_xprt;

spin_lock_bh(&xprt->transport_lock);
@@ -701,6 +697,18 @@ rpcrdma_conn_func(struct rpcrdma_ep *ep)
}

/*
+ * This function is called when an async event is posted to
+ * the connection which changes the connection state. All it
+ * does at this point is mark the connection up/down, the rpc
+ * timers do the rest.
+ */
+void
+rpcrdma_conn_func(struct rpcrdma_ep *ep)
+{
+ schedule_delayed_work(&ep->rep_connect_worker, 0);
+}
+
+/*
* This function is called when memory window unbind which we are waiting
* for completes. Just use rr_func (zeroed by upcall) to signal completion.
*/
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 5c07d11..422cf89 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -742,6 +742,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
INIT_CQCOUNT(ep);
ep->rep_ia = ia;
init_waitqueue_head(&ep->rep_connect_wait);
+ INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);

/*
* Create a single cq for receive dto and mw_bind (only ever
@@ -817,6 +818,8 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
dprintk("RPC: %s: entering, connected is %d\n",
__func__, ep->rep_connected);

+ cancel_delayed_work_sync(&ep->rep_connect_worker);
+
if (ia->ri_id->qp) {
rc = rpcrdma_ep_disconnect(ep, ia);
if (rc)
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 98340a3..c620d13 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -43,6 +43,7 @@
#include <linux/wait.h> /* wait_queue_head_t, etc */
#include <linux/spinlock.h> /* spinlock_t, etc */
#include <linux/atomic.h> /* atomic_t, etc */
+#include <linux/workqueue.h> /* struct work_struct */

#include <rdma/rdma_cm.h> /* RDMA connection api */
#include <rdma/ib_verbs.h> /* RDMA verbs api */
@@ -87,6 +88,7 @@ struct rpcrdma_ep {
struct rpc_xprt *rep_xprt; /* for rep_func */
struct rdma_conn_param rep_remote_cma;
struct sockaddr_storage rep_remote_addr;
+ struct delayed_work rep_connect_worker;
};

#define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
@@ -336,6 +338,7 @@ int rpcrdma_deregister_external(struct rpcrdma_mr_seg *,
/*
* RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
*/
+void rpcrdma_connect_worker(struct work_struct *);
void rpcrdma_conn_func(struct rpcrdma_ep *);
void rpcrdma_reply_handler(struct rpcrdma_rep *);