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authorTrond Myklebust <Trond.Myklebust@netapp.com>2008-03-21 16:19:41 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2008-04-19 16:53:20 -0400
commit1e799b673c6b82b336ab13c48b5651d511ca3000 (patch)
tree9954155b2a9bdd72e49a078418ceea6c47bcc609 /net/sunrpc
parentc1d519312dcdf11532fed9f99a8ecc3547ffd9d6 (diff)
SUNRPC: Fix read ordering problems with req->rq_private_buf.len
We want to ensure that req->rq_private_buf.len is updated before req->rq_received, so that call_decode() doesn't use an old value for req->rq_rcv_buf.len. In 'call_decode()' itself, instead of using task->tk_status (which is set using req->rq_received) must use the actual value of req->rq_private_buf.len when deciding whether or not the received RPC reply is too short. Finally ensure that we set req->rq_rcv_buf.len to zero when retrying a request. A typo meant that we were resetting req->rq_private_buf.len in call_decode(), and then clobbering that value with the old rq_rcv_buf.len again in xprt_transmit(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/clnt.c26
-rw-r--r--net/sunrpc/xprt.c3
2 files changed, 15 insertions, 14 deletions
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 522b06849f8..3ae56046451 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1199,18 +1199,6 @@ call_decode(struct rpc_task *task)
task->tk_flags &= ~RPC_CALL_MAJORSEEN;
}
- if (task->tk_status < 12) {
- if (!RPC_IS_SOFT(task)) {
- task->tk_action = call_bind;
- clnt->cl_stats->rpcretrans++;
- goto out_retry;
- }
- dprintk("RPC: %s: too small RPC reply size (%d bytes)\n",
- clnt->cl_protname, task->tk_status);
- task->tk_action = call_timeout;
- goto out_retry;
- }
-
/*
* Ensure that we see all writes made by xprt_complete_rqst()
* before it changed req->rq_received.
@@ -1222,6 +1210,18 @@ call_decode(struct rpc_task *task)
WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
sizeof(req->rq_rcv_buf)) != 0);
+ if (req->rq_rcv_buf.len < 12) {
+ if (!RPC_IS_SOFT(task)) {
+ task->tk_action = call_bind;
+ clnt->cl_stats->rpcretrans++;
+ goto out_retry;
+ }
+ dprintk("RPC: %s: too small RPC reply size (%d bytes)\n",
+ clnt->cl_protname, task->tk_status);
+ task->tk_action = call_timeout;
+ goto out_retry;
+ }
+
/* Verify the RPC header */
p = call_verify(task);
if (IS_ERR(p)) {
@@ -1243,7 +1243,7 @@ out_retry:
task->tk_status = 0;
/* Note: call_verify() may have freed the RPC slot */
if (task->tk_rqstp == req) {
- req->rq_received = req->rq_private_buf.len = 0;
+ req->rq_received = req->rq_rcv_buf.len = 0;
if (task->tk_client->cl_discrtry)
xprt_force_disconnect(task->tk_xprt);
}
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 3ba64f9f84b..5110a4ea7fd 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -757,9 +757,10 @@ void xprt_complete_rqst(struct rpc_task *task, int copied)
task->tk_rtt = (long)jiffies - req->rq_xtime;
list_del_init(&req->rq_list);
+ req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update req->rq_received */
smp_wmb();
- req->rq_received = req->rq_private_buf.len = copied;
+ req->rq_received = copied;
rpc_wake_up_queued_task(&xprt->pending, task);
}
EXPORT_SYMBOL_GPL(xprt_complete_rqst);