[PATCH AUTOSEL for 4.14 148/161] SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context

Sasha Levin
2018-04-09T00:26:25Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

[ Upstream commit 0afa6b4412988019db14c6bfb8c6cbdf120ca9ad ]

Calling __UDPX_INC_STATS() from a preemptible context leads to a
warning of the form:

BUG: using __this_cpu_add() in preemptible [00000000] code: kworker/u5:0/31
caller is xs_udp_data_receive_workfn+0x194/0x270
CPU: 1 PID: 31 Comm: kworker/u5:0 Not tainted 4.15.0-rc8-00076-g90ea9f1 #2
Workqueue: xprtiod xs_udp_data_receive_workfn
Call Trace:
dump_stack+0x85/0xc1
check_preemption_disabled+0xce/0xe0
xs_udp_data_receive_workfn+0x194/0x270
process_one_work+0x318/0x620
worker_thread+0x20a/0x390
? process_one_work+0x620/0x620
kthread+0x120/0x130
? __kthread_bind_mask+0x60/0x60
ret_from_fork+0x24/0x30

Since we're taking a spinlock in those functions anyway, let's fix the
issue by moving the call so that it occurs under the spinlock.

Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
net/sunrpc/xprtsock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 8cb40f8ffa5b..30192abfdc3b 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1069,18 +1069,18 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,

/* Suck it into the iovec, verify checksum if not done by hw. */
if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
- __UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
spin_lock(&xprt->recv_lock);
+ __UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
goto out_unpin;
}

- __UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);

spin_lock_bh(&xprt->transport_lock);
xprt_adjust_cwnd(xprt, task, copied);
spin_unlock_bh(&xprt->transport_lock);
spin_lock(&xprt->recv_lock);
xprt_complete_rqst(task, copied);
+ __UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
out_unpin:
xprt_unpin_rqst(rovr);
out_unlock:
--
2.15.1