From a4f0835c604f80f945ab3e72ffd00547145c4b2b Mon Sep 17 00:00:00 2001 From: Trond Myklebust <Trond.Myklebust@netapp.com> Date: Tue, 8 Jan 2013 09:10:21 -0500 Subject: SUNRPC: Eliminate task->tk_xprt accesses that bypass rcu_dereference() tk_xprt is just a shortcut for tk_client->cl_xprt, however cl_xprt is defined as an __rcu variable. Replace dereferences of tk_xprt with non-rcu dereferences where it is safe to do so. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> --- net/sunrpc/xprt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/sunrpc/xprt.c') diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 33811db8788..738ad59628c 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -430,7 +430,9 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) */ void xprt_release_rqst_cong(struct rpc_task *task) { - __xprt_put_cong(task->tk_xprt, task->tk_rqstp); + struct rpc_rqst *req = task->tk_rqstp; + + __xprt_put_cong(req->rq_xprt, req); } EXPORT_SYMBOL_GPL(xprt_release_rqst_cong); -- cgit v1.2.3-70-g09d2 From 1b092092bf0e2e8b7af1c2a03f615b4e60b05d47 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <Trond.Myklebust@netapp.com> Date: Tue, 8 Jan 2013 09:26:49 -0500 Subject: SUNRPC: Pass a pointer to struct rpc_xprt to the connect callback Avoid another RCU dereference by passing the pointer to struct rpc_xprt from the caller. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> --- include/linux/sunrpc/xprt.h | 2 +- net/sunrpc/xprt.c | 2 +- net/sunrpc/xprtrdma/transport.c | 3 +-- net/sunrpc/xprtsock.c | 4 ++-- 4 files changed, 5 insertions(+), 6 deletions(-) (limited to 'net/sunrpc/xprt.c') diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 951cb9b7d02..7dd598a5c9a 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -117,7 +117,7 @@ struct rpc_xprt_ops { void (*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task); void (*rpcbind)(struct rpc_task *task); void (*set_port)(struct rpc_xprt *xprt, unsigned short port); - void (*connect)(struct rpc_task *task); + void (*connect)(struct rpc_xprt *xprt, struct rpc_task *task); void * (*buf_alloc)(struct rpc_task *task, size_t size); void (*buf_free)(void *buffer); int (*send_request)(struct rpc_task *task); diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 738ad59628c..774025109e2 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -724,7 +724,7 @@ void xprt_connect(struct rpc_task *task) if (xprt_test_and_set_connecting(xprt)) return; xprt->stat.connect_start = jiffies; - xprt->ops->connect(task); + xprt->ops->connect(xprt, task); } } diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index b357c528d29..d0074289708 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -426,9 +426,8 @@ xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port) } static void -xprt_rdma_connect(struct rpc_task *task) +xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task) { - struct rpc_xprt *xprt = (struct rpc_xprt *)task->tk_xprt; struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); if (r_xprt->rx_ep.rep_connected != 0) { diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 25838901c97..1897181d743 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -2205,6 +2205,7 @@ out: /** * xs_connect - connect a socket to a remote endpoint + * @xprt: pointer to transport structure * @task: address of RPC task that manages state of connect request * * TCP: If the remote end dropped the connection, delay reconnecting. @@ -2216,9 +2217,8 @@ out: * If a UDP socket connect fails, the delay behavior here prevents * retry floods (hard mounts). */ -static void xs_connect(struct rpc_task *task) +static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task) { - struct rpc_xprt *xprt = task->tk_xprt; struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt); if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) { -- cgit v1.2.3-70-g09d2 From 6a24dfb645dbcb05b34d08b991d082bdaa3ff072 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <Trond.Myklebust@netapp.com> Date: Tue, 8 Jan 2013 09:48:15 -0500 Subject: SUNRPC: Pass pointers to struct rpc_xprt to the congestion window Avoid access to task->tk_xprt Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> --- include/linux/sunrpc/xprt.h | 4 ++-- net/sunrpc/xprt.c | 6 +++--- net/sunrpc/xprtsock.c | 6 +++--- 3 files changed, 8 insertions(+), 8 deletions(-) (limited to 'net/sunrpc/xprt.c') diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 7dd598a5c9a..30834be0301 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -122,7 +122,7 @@ struct rpc_xprt_ops { void (*buf_free)(void *buffer); int (*send_request)(struct rpc_task *task); void (*set_retrans_timeout)(struct rpc_task *task); - void (*timer)(struct rpc_task *task); + void (*timer)(struct rpc_xprt *xprt, struct rpc_task *task); void (*release_request)(struct rpc_task *task); void (*close)(struct rpc_xprt *xprt); void (*destroy)(struct rpc_xprt *xprt); @@ -313,7 +313,7 @@ void xprt_set_retrans_timeout_rtt(struct rpc_task *task); void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status); void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action); void xprt_write_space(struct rpc_xprt *xprt); -void xprt_adjust_cwnd(struct rpc_task *task, int result); +void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result); struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid); void xprt_complete_rqst(struct rpc_task *task, int copied); void xprt_release_rqst_cong(struct rpc_task *task); diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 774025109e2..e1e439ea177 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -438,15 +438,15 @@ EXPORT_SYMBOL_GPL(xprt_release_rqst_cong); /** * xprt_adjust_cwnd - adjust transport congestion window + * @xprt: pointer to xprt * @task: recently completed RPC request used to adjust window * @result: result code of completed RPC request * * We use a time-smoothed congestion estimator to avoid heavy oscillation. */ -void xprt_adjust_cwnd(struct rpc_task *task, int result) +void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result) { struct rpc_rqst *req = task->tk_rqstp; - struct rpc_xprt *xprt = task->tk_xprt; unsigned long cwnd = xprt->cwnd; if (result >= 0 && cwnd <= xprt->cong) { @@ -834,7 +834,7 @@ static void xprt_timer(struct rpc_task *task) spin_lock_bh(&xprt->transport_lock); if (!req->rq_reply_bytes_recvd) { if (xprt->ops->timer) - xprt->ops->timer(task); + xprt->ops->timer(xprt, task); } else task->tk_status = 0; spin_unlock_bh(&xprt->transport_lock); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index f7d6e4f8c16..37cbda63f45 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1005,7 +1005,7 @@ static void xs_udp_data_ready(struct sock *sk, int len) UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS); - xprt_adjust_cwnd(task, copied); + xprt_adjust_cwnd(xprt, task, copied); xprt_complete_rqst(task, copied); out_unlock: @@ -1646,9 +1646,9 @@ static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t * * Adjust the congestion window after a retransmit timeout has occurred. */ -static void xs_udp_timer(struct rpc_task *task) +static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task) { - xprt_adjust_cwnd(task, -ETIMEDOUT); + xprt_adjust_cwnd(xprt, task, -ETIMEDOUT); } static unsigned short xs_get_random_port(void) -- cgit v1.2.3-70-g09d2 From 45bc0dce9879505d6fd9ff68dcd0359fb260dfd7 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <Trond.Myklebust@netapp.com> Date: Tue, 8 Jan 2013 10:03:22 -0500 Subject: SUNRPC: Fix an RCU dereference in xprt_reserve Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> --- net/sunrpc/xprt.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/sunrpc/xprt.c') diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index e1e439ea177..7f3a01a8cae 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1093,7 +1093,7 @@ EXPORT_SYMBOL_GPL(xprt_free); */ void xprt_reserve(struct rpc_task *task) { - struct rpc_xprt *xprt = task->tk_xprt; + struct rpc_xprt *xprt; task->tk_status = 0; if (task->tk_rqstp != NULL) @@ -1101,7 +1101,10 @@ void xprt_reserve(struct rpc_task *task) task->tk_timeout = 0; task->tk_status = -EAGAIN; + rcu_read_lock(); + xprt = rcu_dereference(task->tk_client->cl_xprt); xprt->ops->alloc_slot(xprt, task); + rcu_read_unlock(); } static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt) -- cgit v1.2.3-70-g09d2 From ad2368d6f5ec6467b9503176e9fb878daf999629 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <Trond.Myklebust@netapp.com> Date: Tue, 8 Jan 2013 10:08:33 -0500 Subject: SUNRPC: Avoid RCU dereferences in the transport bind and connect code Avoid an RCU dereference by removing task->tk_xprt Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> --- net/sunrpc/clnt.c | 4 ++-- net/sunrpc/xprt.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'net/sunrpc/xprt.c') diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 6b3411ba23f..a9f7906c1a6 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1508,7 +1508,7 @@ rpc_xdr_encode(struct rpc_task *task) static void call_bind(struct rpc_task *task) { - struct rpc_xprt *xprt = task->tk_xprt; + struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; dprint_status(task); @@ -1602,7 +1602,7 @@ retry_timeout: static void call_connect(struct rpc_task *task) { - struct rpc_xprt *xprt = task->tk_xprt; + struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; dprintk("RPC: %5u call_connect xprt %p %s connected\n", task->tk_pid, xprt, diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 7f3a01a8cae..846c34fdee9 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -697,7 +697,7 @@ out_abort: */ void xprt_connect(struct rpc_task *task) { - struct rpc_xprt *xprt = task->tk_xprt; + struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid, xprt, (xprt_connected(xprt) ? "is" : "is not")); @@ -730,7 +730,7 @@ void xprt_connect(struct rpc_task *task) static void xprt_connect_status(struct rpc_task *task) { - struct rpc_xprt *xprt = task->tk_xprt; + struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; if (task->tk_status == 0) { xprt->stat.connect_count++; -- cgit v1.2.3-70-g09d2