Separate out the action of adding a request to the reply queue so that the
backchannel code can simply skip calling it altogether.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
include/linux/sunrpc/xprt.h | 1 +
net/sunrpc/backchannel_rqst.c | 1 -
net/sunrpc/clnt.c | 5 ++
net/sunrpc/xprt.c | 126 +++++++++++++++++++-----------
net/sunrpc/xprtrdma/backchannel.c | 1 -
5 files changed, 88 insertions(+), 46 deletions(-)
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index c25d0a5fda69..0250294c904a 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -334,6 +334,7 @@ void xprt_free_slot(struct rpc_xprt *xprt,
struct rpc_rqst *req);
void xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
bool xprt_prepare_transmit(struct rpc_task *task);
+void xprt_request_enqueue_receive(struct rpc_task *task);
void xprt_transmit(struct rpc_task *task);
void xprt_end_transmit(struct rpc_task *task);
int xprt_adjust_timeout(struct rpc_rqst *req);
diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 3c15a99b9700..fa5ba6ed3197 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -91,7 +91,6 @@ struct rpc_rqst *xprt_alloc_bc_req(struct rpc_xprt *xprt, gfp_t gfp_flags)
return NULL;
req->rq_xprt = xprt;
- INIT_LIST_HEAD(&req->rq_list);
INIT_LIST_HEAD(&req->rq_bc_list);
/* Preallocate one XDR receive buffer */
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index a858366cd15d..414966273a3f 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1962,6 +1962,11 @@ call_transmit(struct rpc_task *task)
return;
}
}
+
+ /* Add task to reply queue before transmission to avoid races */
+ if (rpc_reply_expected(task))
+ xprt_request_enqueue_receive(task);
+
if (!xprt_prepare_transmit(task))
return;
task->tk_action = call_transmit_status;
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 6e3d4b4ee79e..d8f870b5dd46 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -888,6 +888,61 @@ static void xprt_wait_on_pinned_rqst(struct rpc_rqst *req)
wait_var_event(&req->rq_pin, !xprt_is_pinned_rqst(req));
}
+static bool
+xprt_request_data_received(struct rpc_task *task)
+{
+ return !test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) &&
+ READ_ONCE(task->tk_rqstp->rq_reply_bytes_recvd) != 0;
+}
+
+static bool
+xprt_request_need_enqueue_receive(struct rpc_task *task, struct rpc_rqst *req)
+{
+ return !xprt_request_data_received(task);
+}
+
+/**
+ * xprt_request_enqueue_receive - Add an request to the receive queue
+ * @task: RPC task
+ *
+ */
+void
+xprt_request_enqueue_receive(struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_xprt *xprt = req->rq_xprt;
+
+ if (!xprt_request_need_enqueue_receive(task, req))
+ return;
+ spin_lock(&xprt->queue_lock);
+
+ /* Update the softirq receive buffer */
+ memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
+ sizeof(req->rq_private_buf));
+
+ /* Add request to the receive list */
+ list_add_tail(&req->rq_list, &xprt->recv);
+ set_bit(RPC_TASK_NEED_RECV, &task->tk_runstate);
+ spin_unlock(&xprt->queue_lock);
+
+ xprt_reset_majortimeo(req);
+ /* Turn off autodisconnect */
+ del_singleshot_timer_sync(&xprt->timer);
+}
+
+/**
+ * xprt_request_dequeue_receive_locked - Remove a request from the receive queue
+ * @task: RPC task
+ *
+ * Caller must hold xprt->queue_lock.
+ */
+static void
+xprt_request_dequeue_receive_locked(struct rpc_task *task)
+{
+ if (test_and_clear_bit(RPC_TASK_NEED_RECV, &task->tk_runstate))
+ list_del(&task->tk_rqstp->rq_list);
+}
+
/**
* xprt_update_rtt - Update RPC RTT statistics
* @task: RPC request that recently completed
@@ -927,24 +982,16 @@ void xprt_complete_rqst(struct rpc_task *task, int copied)
xprt->stat.recvs++;
- list_del_init(&req->rq_list);
req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update */
/* req->rq_reply_bytes_recvd */
smp_wmb();
req->rq_reply_bytes_recvd = copied;
- clear_bit(RPC_TASK_NEED_RECV, &task->tk_runstate);
+ xprt_request_dequeue_receive_locked(task);
rpc_wake_up_queued_task(&xprt->pending, task);
}
EXPORT_SYMBOL_GPL(xprt_complete_rqst);
-static bool
-xprt_request_data_received(struct rpc_task *task)
-{
- return !test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) &&
- task->tk_rqstp->rq_reply_bytes_recvd != 0;
-}
-
static void xprt_timer(struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
@@ -1018,32 +1065,15 @@ void xprt_transmit(struct rpc_task *task)
dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
- if (!req->rq_reply_bytes_recvd) {
-
+ if (!req->rq_bytes_sent) {
+ if (xprt_request_data_received(task))
+ return;
/* Verify that our message lies in the RPCSEC_GSS window */
- if (!req->rq_bytes_sent && rpcauth_xmit_need_reencode(task)) {
+ if (rpcauth_xmit_need_reencode(task)) {
task->tk_status = -EBADMSG;
return;
}
-
- if (list_empty(&req->rq_list) && rpc_reply_expected(task)) {
- /*
- * Add to the list only if we're expecting a reply
- */
- /* Update the softirq receive buffer */
- memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
- sizeof(req->rq_private_buf));
- /* Add request to the receive list */
- spin_lock(&xprt->queue_lock);
- list_add_tail(&req->rq_list, &xprt->recv);
- set_bit(RPC_TASK_NEED_RECV, &task->tk_runstate);
- spin_unlock(&xprt->queue_lock);
- xprt_reset_majortimeo(req);
- /* Turn off autodisconnect */
- del_singleshot_timer_sync(&xprt->timer);
- }
- } else if (xprt_request_data_received(task) && !req->rq_bytes_sent)
- return;
+ }
connect_cookie = xprt->connect_cookie;
status = xprt->ops->send_request(task);
@@ -1285,7 +1315,6 @@ xprt_request_init(struct rpc_task *task)
struct rpc_xprt *xprt = task->tk_xprt;
struct rpc_rqst *req = task->tk_rqstp;
- INIT_LIST_HEAD(&req->rq_list);
req->rq_timeout = task->tk_client->cl_timeout->to_initval;
req->rq_task = task;
req->rq_xprt = xprt;
@@ -1355,6 +1384,26 @@ void xprt_retry_reserve(struct rpc_task *task)
xprt_do_reserve(xprt, task);
}
+static void
+xprt_request_dequeue_all(struct rpc_task *task, struct rpc_rqst *req)
+{
+ struct rpc_xprt *xprt = req->rq_xprt;
+
+ if (test_bit(RPC_TASK_NEED_RECV, &task->tk_runstate) ||
+ xprt_is_pinned_rqst(req)) {
+ spin_lock(&xprt->queue_lock);
+ xprt_request_dequeue_receive_locked(task);
+ while (xprt_is_pinned_rqst(req)) {
+ set_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
+ spin_unlock(&xprt->queue_lock);
+ xprt_wait_on_pinned_rqst(req);
+ spin_lock(&xprt->queue_lock);
+ clear_bit(RPC_TASK_MSG_PIN_WAIT, &task->tk_runstate);
+ }
+ spin_unlock(&xprt->queue_lock);
+ }
+}
+
/**
* xprt_release - release an RPC request slot
* @task: task which is finished with the slot
@@ -1379,18 +1428,7 @@ void xprt_release(struct rpc_task *task)
task->tk_ops->rpc_count_stats(task, task->tk_calldata);
else if (task->tk_client)
rpc_count_iostats(task, task->tk_client->cl_metrics);
- spin_lock(&xprt->queue_lock);
- if (!list_empty(&req->rq_list)) {
- list_del_init(&req->rq_list);
- if (xprt_is_pinned_rqst(req)) {
- set_bit(RPC_TASK_MSG_PIN_WAIT, &req->rq_task->tk_runstate);
- spin_unlock(&xprt->queue_lock);
- xprt_wait_on_pinned_rqst(req);
- spin_lock(&xprt->queue_lock);
- clear_bit(RPC_TASK_MSG_PIN_WAIT, &req->rq_task->tk_runstate);
- }
- }
- spin_unlock(&xprt->queue_lock);
+ xprt_request_dequeue_all(task, req);
spin_lock_bh(&xprt->transport_lock);
xprt->ops->release_xprt(xprt, task);
if (xprt->ops->release_request)
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index 90adeff4c06b..ed58761e6b23 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -51,7 +51,6 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt,
rqst = &req->rl_slot;
rqst->rq_xprt = xprt;
- INIT_LIST_HEAD(&rqst->rq_list);
INIT_LIST_HEAD(&rqst->rq_bc_list);
__set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
spin_lock_bh(&xprt->bc_pa_lock);
--
2.17.1
